Repository: zhmcclient/zhmc-prometheus-exporter (language: python)

Issue:
Using prometheus_client 0.20.0.post1
This change uses prometheus_client version 0.20.0.post1 from my fork at https://github.com/andy-maier/client_python/releases/tag/0.20.0.post1
Use official prometheus_client version 0.21.0, once released
PR #558 vendorized prometheus_client version 0.20.0.post1 from my fork.

This ticket is to remove the vendorizing again, and to use the officially released version that contains these two PRs:
* https://github.com/prometheus/client_python/pull/1051
* https://github.com/prometheus/client_python/pull/1019 - released in 0.21.0


Discussion / hints:

[![Coverage Status](https://coveralls.io/builds/68913092/badge)](https://coveralls.io/builds/68913092)

coverage: 0.0%. remained the same
when pulling **30184f16b12e437d8075f32955fc51f469f1bd44 on andy/client-0.2.0.post1**
into **a21b2cff5663dfb483b4667f1c9565e4eb4d2326 on master**.



Fix patch:
diff --git a/Makefile b/Makefile
index b21d63c6..c5784ee4 100644
--- a/Makefile
+++ b/Makefile
@@ -100,6 +100,11 @@ package_dir := $(package_name)
 package_py_files := \
     $(wildcard $(package_dir)/*.py) \
     $(wildcard $(package_dir)/*/*.py) \
+    $(wildcard $(package_dir)/*/*/*.py) \
+    $(wildcard $(package_dir)/*/*/*/*.py) \
+
+src_py_files := \
+    $(wildcard $(package_dir)/*.py) \
 
 test_dir := tests
 test_py_files := \
@@ -237,14 +242,14 @@ develop: $(done_dir)/develop_$(pymn)_$(PACKAGE_LEVEL).done
 .PHONY: check
 check: $(done_dir)/develop_$(pymn)_$(PACKAGE_LEVEL).done
 	@echo "Makefile: Performing flake8 checks with PACKAGE_LEVEL=$(PACKAGE_LEVEL)"
-	flake8 --config .flake8 $(package_py_files) $(test_py_files) setup.py $(doc_dir)/conf.py
+	flake8 --config .flake8 $(src_py_files) $(test_py_files) setup.py $(doc_dir)/conf.py
 	@echo "Makefile: Done performing flake8 checks"
 	@echo "Makefile: $@ done."
 
 .PHONY: pylint
 pylint: $(done_dir)/develop_$(pymn)_$(PACKAGE_LEVEL).done
 	@echo "Makefile: Performing pylint checks with PACKAGE_LEVEL=$(PACKAGE_LEVEL)"
-	pylint --rcfile=.pylintrc --disable=fixme $(package_py_files) $(test_py_files) setup.py $(doc_dir)/conf.py
+	pylint --rcfile=.pylintrc --disable=fixme $(src_py_files) $(test_py_files) setup.py $(doc_dir)/conf.py
 	@echo "Makefile: Done performing pylint checks"
 	@echo "Makefile: $@ done."
 
diff --git a/docs/changes.rst b/docs/changes.rst
index f3a1745d..9744ad54 100644
--- a/docs/changes.rst
+++ b/docs/changes.rst
@@ -42,8 +42,8 @@ Released: not yet
 
 * Fixed AttributeError when using 'storage_groups' on 'Client' object.
 
-* Used a forked version 0.20.0.post1 of the 'prometheus_client' package to pick
-  up the following fixes:
+* Vendorized a forked version 0.20.0.post1 of the 'prometheus_client' package
+  to pick up the following fixes:
 
   - Fixed HTTP verb tampering test failures. (issue #494)
   - Fixed vulnerabilities in Prometheus server detected by testssl.sh.
diff --git a/requirements.txt b/requirements.txt
index 8add067d..e5289900 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -14,8 +14,8 @@ zhmcclient>=1.14.0
 # prometheus-client 0.20.0.post1 (on forked repo) adds the following PRs:
 # - Removed CBC ciphers to address CVE-2013-0169 (LUCKY13) (PR https://github.com/prometheus/client_python/pull/1051)
 # - Reject invalid HTTP methods and resources (PR https://github.com/prometheus/client_python/pull/1019)
+# For now, 0.20.0.post1 has been vendorized.
 # TODO: Use official prometheus-client version (0.21.0 ?) with these PRs once released.
-prometheus-client @ git+https://github.com/andy-maier/client_python.git@release_0.20.0.post1
 # prometheus-client>=0.21.0
 
 urllib3>=1.26.19
diff --git a/setup.py b/setup.py
index c0ec610a..a2e6fe3c 100644
--- a/setup.py
+++ b/setup.py
@@ -82,7 +82,12 @@ def read_file(a_file):
     name='zhmc_prometheus_exporter',
     version=package_version,
     packages=[
-        'zhmc_prometheus_exporter'
+        'zhmc_prometheus_exporter',
+        'zhmc_prometheus_exporter.vendor',
+        'zhmc_prometheus_exporter.vendor.prometheus_client',
+        'zhmc_prometheus_exporter.vendor.prometheus_client.bridge',
+        'zhmc_prometheus_exporter.vendor.prometheus_client.openmetrics',
+        'zhmc_prometheus_exporter.vendor.prometheus_client.twisted',
     ],
     package_data={
         'zhmc_prometheus_exporter': ['schemas/*.yaml'],
diff --git a/zhmc_prometheus_exporter/vendor/__init__.py b/zhmc_prometheus_exporter/vendor/__init__.py
new file mode 100644
index 00000000..785fb7be
--- /dev/null
+++ b/zhmc_prometheus_exporter/vendor/__init__.py
@@ -0,0 +1,4 @@
+# Versions of the vendored packages:
+
+# prometheus_client: https://github.com/andy-maier/client_python/releases/tag/0.20.0.post1
+prometheus_client_version = '0.20.0.post1'
diff --git a/zhmc_prometheus_exporter/vendor/prometheus_client/__init__.py b/zhmc_prometheus_exporter/vendor/prometheus_client/__init__.py
new file mode 100644
index 00000000..84a7ba82
--- /dev/null
+++ b/zhmc_prometheus_exporter/vendor/prometheus_client/__init__.py
@@ -0,0 +1,72 @@
+#!/usr/bin/env python
+
+from . import (
+    exposition, gc_collector, metrics, metrics_core, platform_collector,
+    process_collector, registry,
+)
+from .exposition import (
+    CONTENT_TYPE_LATEST, delete_from_gateway, generate_latest,
+    instance_ip_grouping_key, make_asgi_app, make_wsgi_app, MetricsHandler,
+    push_to_gateway, pushadd_to_gateway, start_http_server, start_wsgi_server,
+    write_to_textfile,
+)
+from .gc_collector import GC_COLLECTOR, GCCollector
+from .metrics import (
+    Counter, disable_created_metrics, enable_created_metrics, Enum, Gauge,
+    Histogram, Info, Summary,
+)
+from .metrics_core import Metric
+from .platform_collector import PLATFORM_COLLECTOR, PlatformCollector
+from .process_collector import PROCESS_COLLECTOR, ProcessCollector
+from .registry import CollectorRegistry, REGISTRY
+
+__all__ = (
+    'CollectorRegistry',
+    'REGISTRY',
+    'Metric',
+    'Counter',
+    'Gauge',
+    'Summary',
+    'Histogram',
+    'Info',
+    'Enum',
+    'enable_created_metrics',
+    'disable_created_metrics',
+    'CONTENT_TYPE_LATEST',
+    'generate_latest',
+    'MetricsHandler',
+    'make_wsgi_app',
+    'make_asgi_app',
+    'start_http_server',
+    'start_wsgi_server',
+    'write_to_textfile',
+    'push_to_gateway',
+    'pushadd_to_gateway',
+    'delete_from_gateway',
+    'instance_ip_grouping_key',
+    'ProcessCollector',
+    'PROCESS_COLLECTOR',
+    'PlatformCollector',
+    'PLATFORM_COLLECTOR',
+    'GCCollector',
+    'GC_COLLECTOR',
+)
+
+if __name__ == '__main__':
+    c = Counter('cc', 'A counter')
+    c.inc()
+
+    g = Gauge('gg', 'A gauge')
+    g.set(17)
+
+    s = Summary('ss', 'A summary', ['a', 'b'])
+    s.labels('c', 'd').observe(17)
+
+    h = Histogram('hh', 'A histogram')
+    h.observe(.6)
+
+    start_http_server(8000)
+    import time
+
+    while True:
+        time.sleep(1)
diff --git a/zhmc_prometheus_exporter/vendor/prometheus_client/asgi.py b/zhmc_prometheus_exporter/vendor/prometheus_client/asgi.py
new file mode 100644
index 00000000..e1864b8b
--- /dev/null
+++ b/zhmc_prometheus_exporter/vendor/prometheus_client/asgi.py
@@ -0,0 +1,40 @@
+from typing import Callable
+from urllib.parse import parse_qs
+
+from .exposition import _bake_output
+from .registry import CollectorRegistry, REGISTRY
+
+
+def make_asgi_app(registry: CollectorRegistry = REGISTRY, disable_compression: bool = False) -> Callable:
+    """Create a ASGI app which serves the metrics from a registry."""
+
+    async def prometheus_app(scope, receive, send):
+        assert scope.get("type") == "http"
+        # Prepare parameters
+        params = parse_qs(scope.get('query_string', b''))
+        accept_header = ",".join([
+            value.decode("utf8") for (name, value) in scope.get('headers')
+            if name.decode("utf8").lower() == 'accept'
+        ])
+        accept_encoding_header = ",".join([
+            value.decode("utf8") for (name, value) in scope.get('headers')
+            if name.decode("utf8").lower() == 'accept-encoding'
+        ])
+        # Bake output
+        status, headers, output = _bake_output(registry, accept_header, accept_encoding_header, params, disable_compression)
+        formatted_headers = []
+        for header in headers:
+            formatted_headers.append(tuple(x.encode('utf8') for x in header))
+        # Return output
+        payload = await receive()
+        if payload.get("type") == "http.request":
+            await send(
+                {
+                    "type": "http.response.start",
+                    "status": int(status.split(' ')[0]),
+                    "headers": formatted_headers,
+                }
+            )
+            await send({"type": "http.response.body", "body": output})
+
+    return prometheus_app
diff --git a/zhmc_prometheus_exporter/vendor/prometheus_client/bridge/__init__.py b/zhmc_prometheus_exporter/vendor/prometheus_client/bridge/__init__.py
new file mode 100644
index 00000000..e69de29b
diff --git a/zhmc_prometheus_exporter/vendor/prometheus_client/bridge/graphite.py b/zhmc_prometheus_exporter/vendor/prometheus_client/bridge/graphite.py
new file mode 100755
index 00000000..8cadbedc
--- /dev/null
+++ b/zhmc_prometheus_exporter/vendor/prometheus_client/bridge/graphite.py
@@ -0,0 +1,94 @@
+#!/usr/bin/env python
+
+import logging
+import re
+import socket
+import threading
+import time
+from timeit import default_timer
+from typing import Callable, Tuple
+
+from ..registry import CollectorRegistry, REGISTRY
+
+# Roughly, have to keep to what works as a file name.
+# We also remove periods, so labels can be distinguished.
+
+_INVALID_GRAPHITE_CHARS = re.compile(r"[^a-zA-Z0-9_-]")
+
+
+def _sanitize(s):
+    return _INVALID_GRAPHITE_CHARS.sub('_', s)
+
+
+class _RegularPush(threading.Thread):
+    def __init__(self, pusher, interval, prefix):
+        super().__init__()
+        self._pusher = pusher
+        self._interval = interval
+        self._prefix = prefix
+
+    def run(self):
+        wait_until = default_timer()
+        while True:
+            while True:
+                now = default_timer()
+                if now >= wait_until:
+                    # May need to skip some pushes.
+                    while wait_until < now:
+                        wait_until += self._interval
+                    break
+                # time.sleep can return early.
+                time.sleep(wait_until - now)
+            try:
+                self._pusher.push(prefix=self._prefix)
+            except OSError:
+                logging.exception("Push failed")
+
+
+class GraphiteBridge:
+    def __init__(self,
+                 address: Tuple[str, int],
+                 registry: CollectorRegistry = REGISTRY,
+                 timeout_seconds: float = 30,
+                 _timer: Callable[[], float] = time.time,
+                 tags: bool = False,
+                 ):
+        self._address = address
+        self._registry = registry
+        self._tags = tags
+        self._timeout = timeout_seconds
+        self._timer = _timer
+
+    def push(self, prefix: str = '') -> None:
+        now = int(self._timer())
+        output = []
+
+        prefixstr = ''
+        if prefix:
+            prefixstr = prefix + '.'
+
+        for metric in self._registry.collect():
+            for s in metric.samples:
+                if s.labels:
+                    if self._tags:
+                        sep = ';'
+                        fmt = '{0}={1}'
+                    else:
+                        sep = '.'
+                        fmt = '{0}.{1}'
+                    labelstr = sep + sep.join(
+                        [fmt.format(
+                            _sanitize(k), _sanitize(v))
+                            for k, v in sorted(s.labels.items())])
+                else:
+                    labelstr = ''
+                output.append(f'{prefixstr}{_sanitize(s.name)}{labelstr} {float(s.value)} {now}\n')
+
+        conn = socket.create_connection(self._address, self._timeout)
+        conn.sendall(''.join(output).encode('ascii'))
+        conn.close()
+
+    def start(self, interval: float = 60.0, prefix: str = '') -> None:
+        t = _RegularPush(self, interval, prefix)
+        t.daemon = True
+        t.start()
diff --git a/zhmc_prometheus_exporter/vendor/prometheus_client/context_managers.py b/zhmc_prometheus_exporter/vendor/prometheus_client/context_managers.py
new file mode 100644
index 00000000..3988ec22
--- /dev/null
+++ b/zhmc_prometheus_exporter/vendor/prometheus_client/context_managers.py
@@ -0,0 +1,82 @@
+from timeit import default_timer
+from types import TracebackType
+from typing import (
+    Any, Callable, Literal, Optional, Tuple, Type, TYPE_CHECKING, TypeVar,
+    Union,
+)
+
+from .decorator import decorate
+
+if TYPE_CHECKING:
+    from . import Counter
+    F = TypeVar("F", bound=Callable[..., Any])
+
+
+class ExceptionCounter:
+    def __init__(self, counter: "Counter", exception: Union[Type[BaseException], Tuple[Type[BaseException], ...]]) -> None:
+        self._counter = counter
+        self._exception = exception
+
+    def __enter__(self) -> None:
+        pass
+
+    def __exit__(self, typ: Optional[Type[BaseException]], value: Optional[BaseException], traceback: Optional[TracebackType]) -> Literal[False]:
+        if isinstance(value, self._exception):
+            self._counter.inc()
+        return False
+
+    def __call__(self, f: "F") -> "F":
+        def wrapped(func, *args, **kwargs):
+            with self:
+                return func(*args, **kwargs)
+
+        return decorate(f, wrapped)
+
+
+class InprogressTracker:
+    def __init__(self, gauge):
+        self._gauge = gauge
+
+    def __enter__(self):
+        self._gauge.inc()
+
+    def __exit__(self, typ, value, traceback):
+        self._gauge.dec()
+
+    def __call__(self, f: "F") -> "F":
+        def wrapped(func, *args, **kwargs):
+            with self:
+                return func(*args, **kwargs)
+
+        return decorate(f, wrapped)
+
+
+class Timer:
+    def __init__(self, metric, callback_name):
+        self._metric = metric
+        self._callback_name = callback_name
+
+    def _new_timer(self):
+        return self.__class__(self._metric, self._callback_name)
+
+    def __enter__(self):
+        self._start = default_timer()
+        return self
+
+    def __exit__(self, typ, value, traceback):
+        # Time can go backwards.
+        duration = max(default_timer() - self._start, 0)
+        callback = getattr(self._metric, self._callback_name)
+        callback(duration)
+
+    def labels(self, *args, **kw):
+        self._metric = self._metric.labels(*args, **kw)
+
+    def __call__(self, f: "F") -> "F":
+        def wrapped(func, *args, **kwargs):
+            # Obtaining new instance of timer every time
+            # ensures thread safety and reentrancy.
+            with self._new_timer():
+                return func(*args, **kwargs)
+
+        return decorate(f, wrapped)
diff --git a/zhmc_prometheus_exporter/vendor/prometheus_client/core.py b/zhmc_prometheus_exporter/vendor/prometheus_client/core.py
new file mode 100644
index 00000000..ad3a4542
--- /dev/null
+++ b/zhmc_prometheus_exporter/vendor/prometheus_client/core.py
@@ -0,0 +1,32 @@
+from .metrics import Counter, Enum, Gauge, Histogram, Info, Summary
+from .metrics_core import (
+    CounterMetricFamily, GaugeHistogramMetricFamily, GaugeMetricFamily,
+    HistogramMetricFamily, InfoMetricFamily, Metric, StateSetMetricFamily,
+    SummaryMetricFamily, UnknownMetricFamily, UntypedMetricFamily,
+)
+from .registry import CollectorRegistry, REGISTRY
+from .samples import Exemplar, Sample, Timestamp
+
+__all__ = (
+    'CollectorRegistry',
+    'Counter',
+    'CounterMetricFamily',
+    'Enum',
+    'Exemplar',
+    'Gauge',
+    'GaugeHistogramMetricFamily',
+    'GaugeMetricFamily',
+    'Histogram',
+    'HistogramMetricFamily',
+    'Info',
+    'InfoMetricFamily',
+    'Metric',
+    'REGISTRY',
+    'Sample',
+    'StateSetMetricFamily',
+    'Summary',
+    'SummaryMetricFamily',
+    'Timestamp',
+    'UnknownMetricFamily',
+    'UntypedMetricFamily',
+)
diff --git a/zhmc_prometheus_exporter/vendor/prometheus_client/decorator.py b/zhmc_prometheus_exporter/vendor/prometheus_client/decorator.py
new file mode 100644
index 00000000..1ad2c977
--- /dev/null
+++ b/zhmc_prometheus_exporter/vendor/prometheus_client/decorator.py
@@ -0,0 +1,427 @@
+# #########################     LICENSE     ############################ #
+
+# Copyright (c) 2005-2016, Michele Simionato
+# All rights reserved.
+
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+
+#   Redistributions of source code must retain the above copyright
+#   notice, this list of conditions and the following disclaimer.
+#   Redistributions in bytecode form must reproduce the above copyright
+#   notice, this list of conditions and the following disclaimer in
+#   the documentation and/or other materials provided with the
+#   distribution.
+
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+# OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
+# TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
+# USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
+# DAMAGE.
+
+"""
+Decorator module, see http://pypi.python.org/pypi/decorator
+for the documentation.
+"""
+from __future__ import print_function
+
+import collections
+import inspect
+import itertools
+import operator
+import re
+import sys
+
+__version__ = '4.0.10'
+
+if sys.version_info >= (3,):
+    from inspect import getfullargspec
+
+
+    def get_init(cls):
+        return cls.__init__
+else:
+    class getfullargspec(object):
+        "A quick and dirty replacement for getfullargspec for Python 2.X"
+
+        def __init__(self, f):
+            self.args, self.varargs, self.varkw, self.defaults = \
+                inspect.getargspec(f)
+            self.kwonlyargs = []
+            self.kwonlydefaults = None
+
+        def __iter__(self):
+            yield self.args
+            yield self.varargs
+            yield self.varkw
+            yield self.defaults
+
+        getargspec = inspect.getargspec
+
+
+    def get_init(cls):
+        return cls.__init__.__func__
+
+# getargspec has been deprecated in Python 3.5
+ArgSpec = collections.namedtuple(
+    'ArgSpec', 'args varargs varkw defaults')
+
+
+def getargspec(f):
+    """A replacement for inspect.getargspec"""
+    spec = getfullargspec(f)
+    return ArgSpec(spec.args, spec.varargs, spec.varkw, spec.defaults)
+
+
+DEF = re.compile(r'\s*def\s*([_\w][_\w\d]*)\s*\(')
+
+
+# basic functionality
+class FunctionMaker(object):
+    """
+    An object with the ability to create functions with a given signature.
+    It has attributes name, doc, module, signature, defaults, dict and
+    methods update and make.
+    """
+
+    # Atomic get-and-increment provided by the GIL
+    _compile_count = itertools.count()
+
+    def __init__(self, func=None, name=None, signature=None,
+                 defaults=None, doc=None, module=None, funcdict=None):
+        self.shortsignature = signature
+        if func:
+            # func can be a class or a callable, but not an instance method
+            self.name = func.__name__
+            if self.name == '<lambda>':  # small hack for lambda functions
+                self.name = '_lambda_'
+            self.doc = func.__doc__
+            self.module = func.__module__
+            if inspect.isfunction(func):
+                argspec = getfullargspec(func)
+                self.annotations = getattr(func, '__annotations__', {})
+                for a in ('args', 'varargs', 'varkw', 'defaults', 'kwonlyargs',
+                          'kwonlydefaults'):
+                    setattr(self, a, getattr(argspec, a))
+                for i, arg in enumerate(self.args):
+                    setattr(self, 'arg%d' % i, arg)
+                if sys.version_info < (3,):  # easy way
+                    self.shortsignature = self.signature = (
+                        inspect.formatargspec(
+                            formatvalue=lambda val: "", *argspec)[1:-1])
+                else:  # Python 3 way
+                    allargs = list(self.args)
+                    allshortargs = list(self.args)
+                    if self.varargs:
+                        allargs.append('*' + self.varargs)
+                        allshortargs.append('*' + self.varargs)
+                    elif self.kwonlyargs:
+                        allargs.append('*')  # single star syntax
+                    for a in self.kwonlyargs:
+                        allargs.append('%s=None' % a)
+                        allshortargs.append('%s=%s' % (a, a))
+                    if self.varkw:
+                        allargs.append('**' + self.varkw)
+                        allshortargs.append('**' + self.varkw)
+                    self.signature = ', '.join(allargs)
+                    self.shortsignature = ', '.join(allshortargs)
+                self.dict = func.__dict__.copy()
+        # func=None happens when decorating a caller
+        if name:
+            self.name = name
+        if signature is not None:
+            self.signature = signature
+        if defaults:
+            self.defaults = defaults
+        if doc:
+            self.doc = doc
+        if module:
+            self.module = module
+        if funcdict:
+            self.dict = funcdict
+        # check existence required attributes
+        assert hasattr(self, 'name')
+        if not hasattr(self, 'signature'):
+            raise TypeError('You are decorating a non function: %s' % func)
+
+    def update(self, func, **kw):
+        "Update the signature of func with the data in self"
+        func.__name__ = self.name
+        func.__doc__ = getattr(self, 'doc', None)
+        func.__dict__ = getattr(self, 'dict', {})
+        func.__defaults__ = getattr(self, 'defaults', ())
+        func.__kwdefaults__ = getattr(self, 'kwonlydefaults', None)
+        func.__annotations__ = getattr(self, 'annotations', None)
+        try:
+            frame = sys._getframe(3)
+        except AttributeError:  # for IronPython and similar implementations
+            callermodule = '?'
+        else:
+            callermodule = frame.f_globals.get('__name__', '?')
+        func.__module__ = getattr(self, 'module', callermodule)
+        func.__dict__.update(kw)
+
+    def make(self, src_templ, evaldict=None, addsource=False, **attrs):
+        "Make a new function from a given template and update the signature"
+        src = src_templ % vars(self)  # expand name and signature
+        evaldict = evaldict or {}
+        mo = DEF.match(src)
+        if mo is None:
+            raise SyntaxError('not a valid function template\n%s' % src)
+        name = mo.group(1)  # extract the function name
+        names = set([name] + [arg.strip(' *') for arg in
+                              self.shortsignature.split(',')])
+        for n in names:
+            if n in ('_func_', '_call_'):
+                raise NameError('%s is overridden in\n%s' % (n, src))
+
+        if not src.endswith('\n'):  # add a newline for old Pythons
+            src += '\n'
+
+        # Ensure each generated function has a unique filename for profilers
+        # (such as cProfile) that depend on the tuple of (<filename>,
+        # <definition line>, <function name>) being unique.
+        filename = '<decorator-gen-%d>' % (next(self._compile_count),)
+        try:
+            code = compile(src, filename, 'single')
+            exec(code, evaldict)
+        except:
+            print('Error in generated code:', file=sys.stderr)
+            print(src, file=sys.stderr)
+            raise
+        func = evaldict[name]
+        if addsource:
+            attrs['__source__'] = src
+        self.update(func, **attrs)
+        return func
+
+    @classmethod
+    def create(cls, obj, body, evaldict, defaults=None,
+               doc=None, module=None, addsource=True, **attrs):
+        """
+        Create a function from the strings name, signature and body.
+        evaldict is the evaluation dictionary. If addsource is true an
+        attribute __source__ is added to the result. The attributes attrs
+        are added, if any.
+        """
+        if isinstance(obj, str):  # "name(signature)"
+            name, rest = obj.strip().split('(', 1)
+            signature = rest[:-1]  # strip a right parens
+            func = None
+        else:  # a function
+            name = None
+            signature = None
+            func = obj
+        self = cls(func, name, signature, defaults, doc, module)
+        ibody = '\n'.join('    ' + line for line in body.splitlines())
+        return self.make('def %(name)s(%(signature)s):\n' + ibody,
+                         evaldict, addsource, **attrs)
+
+
+def decorate(func, caller):
+    """
+    decorate(func, caller) decorates a function using a caller.
+    """
+    evaldict = dict(_call_=caller, _func_=func)
+    fun = FunctionMaker.create(
+        func, "return _call_(_func_, %(shortsignature)s)",
+        evaldict, __wrapped__=func)
+    if hasattr(func, '__qualname__'):
+        fun.__qualname__ = func.__qualname__
+    return fun
+
+
+def decorator(caller, _func=None):
+    """decorator(caller) converts a caller function into a decorator"""
+    if _func is not None:  # return a decorated function
+        # this is obsolete behavior; you should use decorate instead
+        return decorate(_func, caller)
+    # else return a decorator function
+    if inspect.isclass(caller):
+        name = caller.__name__.lower()
+        doc = 'decorator(%s) converts functions/generators into ' \
+              'factories of %s objects' % (caller.__name__, caller.__name__)
+    elif inspect.isfunction(caller):
+        if caller.__name__ == '<lambda>':
+            name = '_lambda_'
+        else:
+            name = caller.__name__
+        doc = caller.__doc__
+    else:  # assume caller is an object with a __call__ method
+        name = caller.__class__.__name__.lower()
+        doc = caller.__call__.__doc__
+    evaldict = dict(_call_=caller, _decorate_=decorate)
+    return FunctionMaker.create(
+        '%s(func)' % name, 'return _decorate_(func, _call_)',
+        evaldict, doc=doc, module=caller.__module__,
+        __wrapped__=caller)
+
+
+# ####################### contextmanager ####################### #
+
+try:  # Python >= 3.2
+    from contextlib import _GeneratorContextManager
+except ImportError:  # Python >= 2.5
+    from contextlib import GeneratorContextManager as _GeneratorContextManager
+
+
+class ContextManager(_GeneratorContextManager):
+    def __call__(self, func):
+        """Context manager decorator"""
+        return FunctionMaker.create(
+            func, "with _self_: return _func_(%(shortsignature)s)",
+            dict(_self_=self, _func_=func), __wrapped__=func)
+
+
+init = getfullargspec(_GeneratorContextManager.__init__)
+n_args = len(init.args)
+if n_args == 2 and not init.varargs:  # (self, genobj) Python 2.7
+    def __init__(self, g, *a, **k):
+        return _GeneratorContextManager.__init__(self, g(*a, **k))
+
+
+    ContextManager.__init__ = __init__
+elif n_args == 2 and init.varargs:  # (self, gen, *a, **k) Python 3.4
+    pass
+elif n_args == 4:  # (self, gen, args, kwds) Python 3.5
+    def __init__(self, g, *a, **k):
+        return _GeneratorContextManager.__init__(self, g, a, k)
+
+
+    ContextManager.__init__ = __init__
+
+contextmanager = decorator(ContextManager)
+
+
+# ############################ dispatch_on ############################ #
+
+def append(a, vancestors):
+    """
+    Append ``a`` to the list of the virtual ancestors, unless it is already
+    included.
+    """
+    add = True
+    for j, va in enumerate(vancestors):
+        if issubclass(va, a):
+            add = False
+            break
+        if issubclass(a, va):
+            vancestors[j] = a
+            add = False
+    if add:
+        vancestors.append(a)
+
+
+# inspired from simplegeneric by P.J. Eby and functools.singledispatch
+def dispatch_on(*dispatch_args):
+    """
+    Factory of decorators turning a function into a generic function
+    dispatching on the given arguments.
+    """
+    assert dispatch_args, 'No dispatch args passed'
+    dispatch_str = '(%s,)' % ', '.join(dispatch_args)
+
+    def check(arguments, wrong=operator.ne, msg=''):
+        """Make sure one passes the expected number of arguments"""
+        if wrong(len(arguments), len(dispatch_args)):
+            raise TypeError('Expected %d arguments, got %d%s' %
+                            (len(dispatch_args), len(arguments), msg))
+
+    def gen_func_dec(func):
+        """Decorator turning a function into a generic function"""
+
+        # first check the dispatch arguments
+        argset = set(getfullargspec(func).args)
+        if not set(dispatch_args) <= argset:
+            raise NameError('Unknown dispatch arguments %s' % dispatch_str)
+
+        typemap = {}
+
+        def vancestors(*types):
+            """
+            Get a list of sets of virtual ancestors for the given types
+            """
+            check(types)
+            ras = [[] for _ in range(len(dispatch_args))]
+            for types_ in typemap:
+                for t, type_, ra in zip(types, types_, ras):
+                    if issubclass(t, type_) and type_ not in t.__mro__:
+                        append(type_, ra)
+            return [set(ra) for ra in ras]
+
+        def ancestors(*types):
+            """
+            Get a list of virtual MROs, one for each type
+            """
+            check(types)
+            lists = []
+            for t, vas in zip(types, vancestors(*types)):
+                n_vas = len(vas)
+                if n_vas > 1:
+                    raise RuntimeError(
+                        'Ambiguous dispatch for %s: %s' % (t, vas))
+                elif n_vas == 1:
+                    va, = vas
+                    mro = type('t', (t, va), {}).__mro__[1:]
+                else:
+                    mro = t.__mro__
+                lists.append(mro[:-1])  # discard t and object
+            return lists
+
+        def register(*types):
+            """
+            Decorator to register an implementation for the given types
+            """
+            check(types)
+
+            def dec(f):
+                check(getfullargspec(f).args, operator.lt, ' in ' + f.__name__)
+                typemap[types] = f
+                return f
+
+            return dec
+
+        def dispatch_info(*types):
+            """
+            An utility to introspect the dispatch algorithm
+            """
+            check(types)
+            lst = []
+            for anc in itertools.product(*ancestors(*types)):
+                lst.append(tuple(a.__name__ for a in anc))
+            return lst
+
+        def _dispatch(dispatch_args, *args, **kw):
+            types = tuple(type(arg) for arg in dispatch_args)
+            try:  # fast path
+                f = typemap[types]
+            except KeyError:
+                pass
+            else:
+                return f(*args, **kw)
+            combinations = itertools.product(*ancestors(*types))
+            next(combinations)  # the first one has been already tried
+            for types_ in combinations:
+                f = typemap.get(types_)
+                if f is not None:
+                    return f(*args, **kw)
+
+            # else call the default implementation
+            return func(*args, **kw)
+
+        return FunctionMaker.create(
+            func, 'return _f_(%s, %%(shortsignature)s)' % dispatch_str,
+            dict(_f_=_dispatch), register=register, default=func,
+            typemap=typemap, vancestors=vancestors, ancestors=ancestors,
+            dispatch_info=dispatch_info, __wrapped__=func)
+
+    gen_func_dec.__name__ = 'dispatch_on' + dispatch_str
+    return gen_func_dec
diff --git a/zhmc_prometheus_exporter/vendor/prometheus_client/exposition.py b/zhmc_prometheus_exporter/vendor/prometheus_client/exposition.py
new file mode 100644
index 00000000..fab139df
--- /dev/null
+++ b/zhmc_prometheus_exporter/vendor/prometheus_client/exposition.py
@@ -0,0 +1,666 @@
+import base64
+from contextlib import closing
+import gzip
+from http.server import BaseHTTPRequestHandler
+import os
+import socket
+from socketserver import ThreadingMixIn
+import ssl
+import sys
+import threading
+from typing import Any, Callable, Dict, List, Optional, Sequence, Tuple, Union
+from urllib.error import HTTPError
+from urllib.parse import parse_qs, quote_plus, urlparse
+from urllib.request import (
+    BaseHandler, build_opener, HTTPHandler, HTTPRedirectHandler, HTTPSHandler,
+    Request,
+)
+from wsgiref.simple_server import make_server, WSGIRequestHandler, WSGIServer
+
+from .openmetrics import exposition as openmetrics
+from .registry import CollectorRegistry, REGISTRY
+from .utils import floatToGoString
+
+__all__ = (
+    'CONTENT_TYPE_LATEST',
+    'delete_from_gateway',
+    'generate_latest',
+    'instance_ip_grouping_key',
+    'make_asgi_app',
+    'make_wsgi_app',
+    'MetricsHandler',
+    'push_to_gateway',
+    'pushadd_to_gateway',
+    'start_http_server',
+    'start_wsgi_server',
+    'write_to_textfile',
+)
+
+CONTENT_TYPE_LATEST = 'text/plain; version=0.0.4; charset=utf-8'
+"""Content type of the latest text format"""
+
+
+class _PrometheusRedirectHandler(HTTPRedirectHandler):
+    """
+    Allow additional methods (e.g. PUT) and data forwarding in redirects.
+
+    Use of this class constitute a user's explicit agreement to the
+    redirect responses the Prometheus client will receive when using it.
+    You should only use this class if you control or otherwise trust the
+    redirect behavior involved and are certain it is safe to full transfer
+    the original request (method and data) to the redirected URL. For
+    example, if you know there is a cosmetic URL redirect in front of a
+    local deployment of a Prometheus server, and all redirects are safe,
+    this is the class to use to handle redirects in that case.
+
+    The standard HTTPRedirectHandler does not forward request data nor
+    does it allow redirected PUT requests (which Prometheus uses for some
+    operations, for example `push_to_gateway`) because these cannot
+    generically guarantee no violations of HTTP RFC 2616 requirements for
+    the user to explicitly confirm redirects that could have unexpected
+    side effects (such as rendering a PUT request non-idempotent or
+    creating multiple resources not named in the original request).
+    """
+
+    def redirect_request(self, req, fp, code, msg, headers, newurl):
+        """
+        Apply redirect logic to a request.
+
+        See parent HTTPRedirectHandler.redirect_request for parameter info.
+
+        If the redirect is disallowed, this raises the corresponding HTTP error.
+        If the redirect can't be determined, return None to allow other handlers
+        to try. If the redirect is allowed, return the new request.
+
+        This method specialized for the case when (a) the user knows that the
+        redirect will not cause unacceptable side effects for any request method,
+        and (b) the user knows that any request data should be passed through to
+        the redirect. If either condition is not met, this should not be used.
+        """
+        # note that requests being provided by a handler will use get_method to
+        # indicate the method, by monkeypatching this, instead of setting the
+        # Request object's method attribute.
+        m = getattr(req, "method", req.get_method())
+        if not (code in (301, 302, 303, 307) and m in ("GET", "HEAD")
+                or code in (301, 302, 303) and m in ("POST", "PUT")):
+            raise HTTPError(req.full_url, code, msg, headers, fp)
+        new_request = Request(
+            newurl.replace(' ', '%20'),  # space escaping in new url if needed.
+            headers=req.headers,
+            origin_req_host=req.origin_req_host,
+            unverifiable=True,
+            data=req.data,
+        )
+        new_request.method = m
+        return new_request
+
+
+def _bake_output(registry, accept_header, accept_encoding_header, params, disable_compression):
+    """Bake output for metrics output."""
+    # Choose the correct plain text format of the output.
+    encoder, content_type = choose_encoder(accept_header)
+    if 'name[]' in params:
+        registry = registry.restricted_registry(params['name[]'])
+    output = encoder(registry)
+    headers = [('Content-Type', content_type)]
+    # If gzip encoding required, gzip the output.
+    if not disable_compression and gzip_accepted(accept_encoding_header):
+        output = gzip.compress(output)
+        headers.append(('Content-Encoding', 'gzip'))
+    return '200 OK', headers, output
+
+
+def make_wsgi_app(registry: CollectorRegistry = REGISTRY, disable_compression: bool = False) -> Callable:
+    """Create a WSGI app which serves the metrics from a registry."""
+
+    def prometheus_app(environ, start_response):
+        # Prepare parameters
+        accept_header = environ.get('HTTP_ACCEPT')
+        accept_encoding_header = environ.get('HTTP_ACCEPT_ENCODING')
+        params = parse_qs(environ.get('QUERY_STRING', ''))
+        method = environ['REQUEST_METHOD']
+
+        if method == 'OPTIONS':
+            status = '200 OK'
+            headers = [('Allow', 'OPTIONS,GET')]
+            output = b''
+        elif method != 'GET':
+            status = '405 Method Not Allowed'
+            headers = [('Allow', 'OPTIONS,GET')]
+            output = '# HTTP {}: {}; use OPTIONS or GET\n'.format(status, method).encode()
+        elif environ['PATH_INFO'] == '/favicon.ico':
+            # Serve empty response for browsers
+            status = '200 OK'
+            headers = [('', '')]
+            output = b''
+        else:
+            # Note: For backwards compatibility, the URI path for GET is not
+            # constrained to the documented /metrics, but any path is allowed.
+            # Bake output
+            status, headers, output = _bake_output(registry, accept_header, accept_encoding_header, params, disable_compression)
+        # Return output
+        start_response(status, headers)
+        return [output]
+
+    return prometheus_app
+
+
+class _SilentHandler(WSGIRequestHandler):
+    """WSGI handler that does not log requests."""
+
+    def log_message(self, format, *args):
+        """Log nothing."""
+
+
+class ThreadingWSGIServer(ThreadingMixIn, WSGIServer):
+    """Thread per request HTTP server."""
+    # Make worker threads "fire and forget". Beginning with Python 3.7 this
+    # prevents a memory leak because ``ThreadingMixIn`` starts to gather all
+    # non-daemon threads in a list in order to join on them at server close.
+    daemon_threads = True
+
+
+def _get_best_family(address, port):
+    """Automatically select address family depending on address"""
+    # HTTPServer defaults to AF_INET, which will not start properly if
+    # binding an ipv6 address is requested.
+    # This function is based on what upstream python did for http.server
+    # in https://github.com/python/cpython/pull/11767
+    infos = socket.getaddrinfo(address, port, type=socket.SOCK_STREAM, flags=socket.AI_PASSIVE)
+    family, _, _, _, sockaddr = next(iter(infos))
+    return family, sockaddr[0]
+
+
+def _get_ssl_ctx(
+        certfile: str,
+        keyfile: str,
+        protocol: int,
+        cafile: Optional[str] = None,
+        capath: Optional[str] = None,
+        client_auth_required: bool = False,
+) -> ssl.SSLContext:
+    """Load context supports SSL."""
+    ssl_cxt = ssl.SSLContext(protocol=protocol)
+
+    if cafile is not None or capath is not None:
+        try:
+            ssl_cxt.load_verify_locations(cafile, capath)
+        except IOError as exc:
+            exc_type = type(exc)
+            msg = str(exc)
+            raise exc_type(f"Cannot load CA certificate chain from file "
+                           f"{cafile!r} or directory {capath!r}: {msg}")
+    else:
+        try:
+            ssl_cxt.load_default_certs(purpose=ssl.Purpose.CLIENT_AUTH)
+        except IOError as exc:
+            exc_type = type(exc)
+            msg = str(exc)
+            raise exc_type(f"Cannot load default CA certificate chain: {msg}")
+
+    if client_auth_required:
+        ssl_cxt.verify_mode = ssl.CERT_REQUIRED
+
+    try:
+        ssl_cxt.load_cert_chain(certfile=certfile, keyfile=keyfile)
+    except IOError as exc:
+        exc_type = type(exc)
+        msg = str(exc)
+        raise exc_type(f"Cannot load server certificate file {certfile!r} or "
+                       f"its private key file {keyfile!r}: {msg}")
+
+    return ssl_cxt
+
+
+def start_wsgi_server(
+        port: int,
+        addr: str = '0.0.0.0',
+        registry: CollectorRegistry = REGISTRY,
+        certfile: Optional[str] = None,
+        keyfile: Optional[str] = None,
+        client_cafile: Optional[str] = None,
+        client_capath: Optional[str] = None,
+        protocol: int = ssl.PROTOCOL_TLS_SERVER,
+        client_auth_required: bool = False,
+) -> Tuple[WSGIServer, threading.Thread]:
+    """Starts a WSGI server for prometheus metrics as a daemon thread."""
+
+    class TmpServer(ThreadingWSGIServer):
+        """Copy of ThreadingWSGIServer to update address_family locally"""
+
+    TmpServer.address_family, addr = _get_best_family(addr, port)
+    app = make_wsgi_app(registry)
+    httpd = make_server(addr, port, app, TmpServer, handler_class=_SilentHandler)
+    if certfile and keyfile:
+        context = _get_ssl_ctx(certfile, keyfile, protocol, client_cafile, client_capath, client_auth_required)
+        httpd.socket = context.wrap_socket(httpd.socket, server_side=True)
+    t = threading.Thread(target=httpd.serve_forever)
+    t.daemon = True
+    t.start()
+
+    return httpd, t
+
+
+start_http_server = start_wsgi_server
+
+
+def generate_latest(registry: CollectorRegistry = REGISTRY) -> bytes:
+    """Returns the metrics from the registry in latest text format as a string."""
+
+    def sample_line(line):
+        if line.labels:
+            labelstr = '{{{0}}}'.format(','.join(
+                ['{}="{}"'.format(
+                    k, v.replace('\\', r'\\').replace('\n', r'\n').replace('"', r'\"'))
+                    for k, v in sorted(line.labels.items())]))
+        else:
+            labelstr = ''
+        timestamp = ''
+        if line.timestamp is not None:
+            # Convert to milliseconds.
+            timestamp = f' {int(float(line.timestamp) * 1000):d}'
+        return f'{line.name}{labelstr} {floatToGoString(line.value)}{timestamp}\n'
+
+    output = []
+    for metric in registry.collect():
+        try:
+            mname = metric.name
+            mtype = metric.type
+            # Munging from OpenMetrics into Prometheus format.
+            if mtype == 'counter':
+                mname = mname + '_total'
+            elif mtype == 'info':
+                mname = mname + '_info'
+                mtype = 'gauge'
+            elif mtype == 'stateset':
+                mtype = 'gauge'
+            elif mtype == 'gaugehistogram':
+                # A gauge histogram is really a gauge,
+                # but this captures the structure better.
+                mtype = 'histogram'
+            elif mtype == 'unknown':
+                mtype = 'untyped'
+
+            output.append('# HELP {} {}\n'.format(
+                mname, metric.documentation.replace('\\', r'\\').replace('\n', r'\n')))
+            output.append(f'# TYPE {mname} {mtype}\n')
+
+            om_samples: Dict[str, List[str]] = {}
+            for s in metric.samples:
+                for suffix in ['_created', '_gsum', '_gcount']:
+                    if s.name == metric.name + suffix:
+                        # OpenMetrics specific sample, put in a gauge at the end.
+                        om_samples.setdefault(suffix, []).append(sample_line(s))
+                        break
+                else:
+                    output.append(sample_line(s))
+        except Exception as exception:
+            exception.args = (exception.args or ('',)) + (metric,)
+            raise
+
+        for suffix, lines in sorted(om_samples.items()):
+            output.append('# HELP {}{} {}\n'.format(metric.name, suffix,
+                                                    metric.documentation.replace('\\', r'\\').replace('\n', r'\n')))
+            output.append(f'# TYPE {metric.name}{suffix} gauge\n')
+            output.extend(lines)
+    return ''.join(output).encode('utf-8')
+
+
+def choose_encoder(accept_header: str) -> Tuple[Callable[[CollectorRegistry], bytes], str]:
+    accept_header = accept_header or ''
+    for accepted in accept_header.split(','):
+        if accepted.split(';')[0].strip() == 'application/openmetrics-text':
+            return (openmetrics.generate_latest,
+                    openmetrics.CONTENT_TYPE_LATEST)
+    return generate_latest, CONTENT_TYPE_LATEST
+
+
+def gzip_accepted(accept_encoding_header: str) -> bool:
+    accept_encoding_header = accept_encoding_header or ''
+    for accepted in accept_encoding_header.split(','):
+        if accepted.split(';')[0].strip().lower() == 'gzip':
+            return True
+    return False
+
+
+class MetricsHandler(BaseHTTPRequestHandler):
+    """HTTP handler that gives metrics from ``REGISTRY``."""
+    registry: CollectorRegistry = REGISTRY
+
+    def do_GET(self) -> None:
+        # Prepare parameters
+        registry = self.registry
+        accept_header = self.headers.get('Accept')
+        accept_encoding_header = self.headers.get('Accept-Encoding')
+        params = parse_qs(urlparse(self.path).query)
+        # Bake output
+        status, headers, output = _bake_output(registry, accept_header, accept_encoding_header, params, False)
+        # Return output
+        self.send_response(int(status.split(' ')[0]))
+        for header in headers:
+            self.send_header(*header)
+        self.end_headers()
+        self.wfile.write(output)
+
+    def log_message(self, format: str, *args: Any) -> None:
+        """Log nothing."""
+
+    @classmethod
+    def factory(cls, registry: CollectorRegistry) -> type:
+        """Returns a dynamic MetricsHandler class tied
+           to the passed registry.
+        """
+        # This implementation relies on MetricsHandler.registry
+        #  (defined above and defaulted to REGISTRY).
+
+        # As we have unicode_literals, we need to create a str()
+        #  object for type().
+        cls_name = str(cls.__name__)
+        MyMetricsHandler = type(cls_name, (cls, object),
+                                {"registry": registry})
+        return MyMetricsHandler
+
+
+def write_to_textfile(path: str, registry: CollectorRegistry) -> None:
+    """Write metrics to the given path.
+
+    This is intended for use with the Node exporter textfile collector.
+    The path must end in .prom for the textfile collector to process it."""
+    tmppath = f'{path}.{os.getpid()}.{threading.current_thread().ident}'
+    with open(tmppath, 'wb') as f:
+        f.write(generate_latest(registry))
+
+    # rename(2) is atomic but fails on Windows if the destination file exists
+    if os.name == 'nt':
+        os.replace(tmppath, path)
+    else:
+        os.rename(tmppath, path)
+
+
+def _make_handler(
+        url: str,
+        method: str,
+        timeout: Optional[float],
+        headers: Sequence[Tuple[str, str]],
+        data: bytes,
+        base_handler: Union[BaseHandler, type],
+) -> Callable[[], None]:
+    def handle() -> None:
+        request = Request(url, data=data)
+        request.get_method = lambda: method  # type: ignore
+        for k, v in headers:
+            request.add_header(k, v)
+        resp = build_opener(base_handler).open(request, timeout=timeout)
+        if resp.code >= 400:
+            raise OSError(f"error talking to pushgateway: {resp.code} {resp.msg}")
+
+    return handle
+
+
+def default_handler(
+        url: str,
+        method: str,
+        timeout: Optional[float],
+        headers: List[Tuple[str, str]],
+        data: bytes,
+) -> Callable[[], None]:
+    """Default handler that implements HTTP/HTTPS connections.
+
+    Used by the push_to_gateway functions. Can be re-used by other handlers."""
+
+    return _make_handler(url, method, timeout, headers, data, HTTPHandler)
+
+
+def passthrough_redirect_handler(
+        url: str,
+        method: str,
+        timeout: Optional[float],
+        headers: List[Tuple[str, str]],
+        data: bytes,
+) -> Callable[[], None]:
+    """
+    Handler that automatically trusts redirect responses for all HTTP methods.
+
+    Augments standard HTTPRedirectHandler capability by permitting PUT requests,
+    preserving the method upon redirect, and passing through all headers and
+    data from the original request. Only use this handler if you control or
+    trust the source of redirect responses you encounter when making requests
+    via the Prometheus client. This handler will simply repeat the identical
+    request, including same method and data, to the new redirect URL."""
+
+    return _make_handler(url, method, timeout, headers, data, _PrometheusRedirectHandler)
+
+
+def basic_auth_handler(
+        url: str,
+        method: str,
+        timeout: Optional[float],
+        headers: List[Tuple[str, str]],
+        data: bytes,
+        username: Optional[str] = None,
+        password: Optional[str] = None,
+) -> Callable[[], None]:
+    """Handler that implements HTTP/HTTPS connections with Basic Auth.
+
+    Sets auth headers using supplied 'username' and 'password', if set.
+    Used by the push_to_gateway functions. Can be re-used by other handlers."""
+
+    def handle():
+        """Handler that implements HTTP Basic Auth.
+        """
+        if username is not None and password is not None:
+            auth_value = f'{username}:{password}'.encode()
+            auth_token = base64.b64encode(auth_value)
+            auth_header = b'Basic ' + auth_token
+            headers.append(('Authorization', auth_header))
+        default_handler(url, method, timeout, headers, data)()
+
+    return handle
+
+
+def tls_auth_handler(
+        url: str,
+        method: str,
+        timeout: Optional[float],
+        headers: List[Tuple[str, str]],
+        data: bytes,
+        certfile: str,
+        keyfile: str,
+        cafile: Optional[str] = None,
+        protocol: int = ssl.PROTOCOL_TLS_CLIENT,
+        insecure_skip_verify: bool = False,
+) -> Callable[[], None]:
+    """Handler that implements an HTTPS connection with TLS Auth.
+
+    The default protocol (ssl.PROTOCOL_TLS_CLIENT) will also enable
+    ssl.CERT_REQUIRED and SSLContext.check_hostname by default. This can be
+    disabled by setting insecure_skip_verify to True.
+
+    Both this handler and the TLS feature on pushgateay are experimental."""
+    context = ssl.SSLContext(protocol=protocol)
+    if cafile is not None:
+        context.load_verify_locations(cafile)
+    else:
+        context.load_default_certs()
+
+    if insecure_skip_verify:
+        context.check_hostname = False
+        context.verify_mode = ssl.CERT_NONE
+
+    context.load_cert_chain(certfile=certfile, keyfile=keyfile)
+    handler = HTTPSHandler(context=context)
+    return _make_handler(url, method, timeout, headers, data, handler)
+
+
+def push_to_gateway(
+        gateway: str,
+        job: str,
+        registry: CollectorRegistry,
+        grouping_key: Optional[Dict[str, Any]] = None,
+        timeout: Optional[float] = 30,
+        handler: Callable = default_handler,
+) -> None:
+    """Push metrics to the given pushgateway.
+
+    `gateway` the url for your push gateway. Either of the form
+              'http://pushgateway.local', or 'pushgateway.local'.
+              Scheme defaults to 'http' if none is provided
+    `job` is the job label to be attached to all pushed metrics
+    `registry` is an instance of CollectorRegistry
+    `grouping_key` please see the pushgateway documentation for details.
+                   Defaults to None
+    `timeout` is how long push will attempt to connect before giving up.
+              Defaults to 30s, can be set to None for no timeout.
+    `handler` is an optional function which can be provided to perform
+              requests to the 'gateway'.
+              Defaults to None, in which case an http or https request
+              will be carried out by a default handler.
+              If not None, the argument must be a function which accepts
+              the following arguments:
+              url, method, timeout, headers, and content
+              May be used to implement additional functionality not
+              supported by the built-in default handler (such as SSL
+              client certicates, and HTTP authentication mechanisms).
+              'url' is the URL for the request, the 'gateway' argument
+              described earlier will form the basis of this URL.
+              'method' is the HTTP method which should be used when
+              carrying out the request.
+              'timeout' requests not successfully completed after this
+              many seconds should be aborted.  If timeout is None, then
+              the handler should not set a timeout.
+              'headers' is a list of ("header-name","header-value") tuples
+              which must be passed to the pushgateway in the form of HTTP
+              request headers.
+              The function should raise an exception (e.g. IOError) on
+              failure.
+              'content' is the data which should be used to form the HTTP
+              Message Body.
+
+    This overwrites all metrics with the same job and grouping_key.
+    This uses the PUT HTTP method."""
+    _use_gateway('PUT', gateway, job, registry, grouping_key, timeout, handler)
+
+
+def pushadd_to_gateway(
+        gateway: str,
+        job: str,
+        registry: Optional[CollectorRegistry],
+        grouping_key: Optional[Dict[str, Any]] = None,
+        timeout: Optional[float] = 30,
+        handler: Callable = default_handler,
+) -> None:
+    """PushAdd metrics to the given pushgateway.
+
+    `gateway` the url for your push gateway. Either of the form
+              'http://pushgateway.local', or 'pushgateway.local'.
+              Scheme defaults to 'http' if none is provided
+    `job` is the job label to be attached to all pushed metrics
+    `registry` is an instance of CollectorRegistry
+    `grouping_key` please see the pushgateway documentation for details.
+                   Defaults to None
+    `timeout` is how long push will attempt to connect before giving up.
+              Defaults to 30s, can be set to None for no timeout.
+    `handler` is an optional function which can be provided to perform
+              requests to the 'gateway'.
+              Defaults to None, in which case an http or https request
+              will be carried out by a default handler.
+              See the 'prometheus_client.push_to_gateway' documentation
+              for implementation requirements.
+
+    This replaces metrics with the same name, job and grouping_key.
+    This uses the POST HTTP method."""
+    _use_gateway('POST', gateway, job, registry, grouping_key, timeout, handler)
+
+
+def delete_from_gateway(
+        gateway: str,
+        job: str,
+        grouping_key: Optional[Dict[str, Any]] = None,
+        timeout: Optional[float] = 30,
+        handler: Callable = default_handler,
+) -> None:
+    """Delete metrics from the given pushgateway.
+
+    `gateway` the url for your push gateway. Either of the form
+              'http://pushgateway.local', or 'pushgateway.local'.
+              Scheme defaults to 'http' if none is provided
+    `job` is the job label to be attached to all pushed metrics
+    `grouping_key` please see the pushgateway documentation for details.
+                   Defaults to None
+    `timeout` is how long delete will attempt to connect before giving up.
+              Defaults to 30s, can be set to None for no timeout.
+    `handler` is an optional function which can be provided to perform
+              requests to the 'gateway'.
+              Defaults to None, in which case an http or https request
+              will be carried out by a default handler.
+              See the 'prometheus_client.push_to_gateway' documentation
+              for implementation requirements.
+
+    This deletes metrics with the given job and grouping_key.
+    This uses the DELETE HTTP method."""
+    _use_gateway('DELETE', gateway, job, None, grouping_key, timeout, handler)
+
+
+def _use_gateway(
+        method: str,
+        gateway: str,
+        job: str,
+        registry: Optional[CollectorRegistry],
+        grouping_key: Optional[Dict[str, Any]],
+        timeout: Optional[float],
+        handler: Callable,
+) -> None:
+    gateway_url = urlparse(gateway)
+    # See https://bugs.python.org/issue27657 for details on urlparse in py>=3.7.6.
+    if not gateway_url.scheme or gateway_url.scheme not in ['http', 'https']:
+        gateway = f'http://{gateway}'
+
+    gateway = gateway.rstrip('/')
+    url = '{}/metrics/{}/{}'.format(gateway, *_escape_grouping_key("job", job))
+
+    data = b''
+    if method != 'DELETE':
+        if registry is None:
+            registry = REGISTRY
+        data = generate_latest(registry)
+
+    if grouping_key is None:
+        grouping_key = {}
+    url += ''.join(
+        '/{}/{}'.format(*_escape_grouping_key(str(k), str(v)))
+        for k, v in sorted(grouping_key.items()))
+
+    handler(
+        url=url, method=method, timeout=timeout,
+        headers=[('Content-Type', CONTENT_TYPE_LATEST)], data=data,
+    )()
+
+
+def _escape_grouping_key(k, v):
+    if v == "":
+        # Per https://github.com/prometheus/pushgateway/pull/346.
+        return k + "@base64", "="
+    elif '/' in v:
+        # Added in Pushgateway 0.9.0.
+        return k + "@base64", base64.urlsafe_b64encode(v.encode("utf-8")).decode("utf-8")
+    else:
+        return k, quote_plus(v)
+
+
+def instance_ip_grouping_key() -> Dict[str, Any]:
+    """Grouping key with instance set to the IP Address of this host."""
+    with closing(socket.socket(socket.AF_INET, socket.SOCK_DGRAM)) as s:
+        if sys.platform == 'darwin':
+            # This check is done this way only on MacOS devices
+            # it is done this way because the localhost method does
+            # not work.
+            # This method was adapted from this StackOverflow answer:
+            # https://stackoverflow.com/a/28950776
+            s.connect(('10.255.255.255', 1))
+        else:
+            s.connect(('localhost', 0))
+
+        return {'instance': s.getsockname()[0]}
+
+
+from .asgi import make_asgi_app  # noqa
diff --git a/zhmc_prometheus_exporter/vendor/prometheus_client/gc_collector.py b/zhmc_prometheus_exporter/vendor/prometheus_client/gc_collector.py
new file mode 100644
index 00000000..06e52dfc
--- /dev/null
+++ b/zhmc_prometheus_exporter/vendor/prometheus_client/gc_collector.py
@@ -0,0 +1,45 @@
+import gc
+import platform
+from typing import Iterable
+
+from .metrics_core import CounterMetricFamily, Metric
+from .registry import Collector, CollectorRegistry, REGISTRY
+
+
+class GCCollector(Collector):
+    """Collector for Garbage collection statistics."""
+
+    def __init__(self, registry: CollectorRegistry = REGISTRY):
+        if not hasattr(gc, 'get_stats') or platform.python_implementation() != 'CPython':
+            return
+        registry.register(self)
+
+    def collect(self) -> Iterable[Metric]:
+        collected = CounterMetricFamily(
+            'python_gc_objects_collected',
+            'Objects collected during gc',
+            labels=['generation'],
+        )
+        uncollectable = CounterMetricFamily(
+            'python_gc_objects_uncollectable',
+            'Uncollectable objects found during GC',
+            labels=['generation'],
+        )
+
+        collections = CounterMetricFamily(
+            'python_gc_collections',
+            'Number of times this generation was collected',
+            labels=['generation'],
+        )
+
+        for gen, stat in enumerate(gc.get_stats()):
+            generation = str(gen)
+            collected.add_metric([generation], value=stat['collected'])
+            uncollectable.add_metric([generation], value=stat['uncollectable'])
+            collections.add_metric([generation], value=stat['collections'])
+
+        return [collected, uncollectable, collections]
+
+
+GC_COLLECTOR = GCCollector()
+"""Default GCCollector in default Registry REGISTRY."""
diff --git a/zhmc_prometheus_exporter/vendor/prometheus_client/metrics.py b/zhmc_prometheus_exporter/vendor/prometheus_client/metrics.py
new file mode 100644
index 00000000..af512115
--- /dev/null
+++ b/zhmc_prometheus_exporter/vendor/prometheus_client/metrics.py
@@ -0,0 +1,776 @@
+import os
+from threading import Lock
+import time
+import types
+from typing import (
+    Any, Callable, Dict, Iterable, List, Literal, Optional, Sequence, Tuple,
+    Type, TypeVar, Union,
+)
+import warnings
+
+from . import values  # retain this import style for testability
+from .context_managers import ExceptionCounter, InprogressTracker, Timer
+from .metrics_core import (
+    Metric, METRIC_LABEL_NAME_RE, METRIC_NAME_RE,
+    RESERVED_METRIC_LABEL_NAME_RE,
+)
+from .registry import Collector, CollectorRegistry, REGISTRY
+from .samples import Exemplar, Sample
+from .utils import floatToGoString, INF
+
+T = TypeVar('T', bound='MetricWrapperBase')
+F = TypeVar("F", bound=Callable[..., Any])
+
+
+def _build_full_name(metric_type, name, namespace, subsystem, unit):
+    full_name = ''
+    if namespace:
+        full_name += namespace + '_'
+    if subsystem:
+        full_name += subsystem + '_'
+    full_name += name
+    if metric_type == 'counter' and full_name.endswith('_total'):
+        full_name = full_name[:-6]  # Munge to OpenMetrics.
+    if unit and not full_name.endswith("_" + unit):
+        full_name += "_" + unit
+    if unit and metric_type in ('info', 'stateset'):
+        raise ValueError('Metric name is of a type that cannot have a unit: ' + full_name)
+    return full_name
+
+
+def _validate_labelname(l):
+    if not METRIC_LABEL_NAME_RE.match(l):
+        raise ValueError('Invalid label metric name: ' + l)
+    if RESERVED_METRIC_LABEL_NAME_RE.match(l):
+        raise ValueError('Reserved label metric name: ' + l)
+
+
+def _validate_labelnames(cls, labelnames):
+    labelnames = tuple(labelnames)
+    for l in labelnames:
+        _validate_labelname(l)
+        if l in cls._reserved_labelnames:
+            raise ValueError('Reserved label metric name: ' + l)
+    return labelnames
+
+
+def _validate_exemplar(exemplar):
+    runes = 0
+    for k, v in exemplar.items():
+        _validate_labelname(k)
+        runes += len(k)
+        runes += len(v)
+    if runes > 128:
+        raise ValueError('Exemplar labels have %d UTF-8 characters, exceeding the limit of 128')
+
+
+def _get_use_created() -> bool:
+    return os.environ.get("PROMETHEUS_DISABLE_CREATED_SERIES", 'False').lower() not in ('true', '1', 't')
+
+
+_use_created = _get_use_created()
+
+
+def disable_created_metrics():
+    """Disable exporting _created metrics on counters, histograms, and summaries."""
+    global _use_created
+    _use_created = False
+
+
+def enable_created_metrics():
+    """Enable exporting _created metrics on counters, histograms, and summaries."""
+    global _use_created
+    _use_created = True
+
+
+class MetricWrapperBase(Collector):
+    _type: Optional[str] = None
+    _reserved_labelnames: Sequence[str] = ()
+
+    def _is_observable(self):
+        # Whether this metric is observable, i.e.
+        # * a metric without label names and values, or
+        # * the child of a labelled metric.
+        return not self._labelnames or (self._labelnames and self._labelvalues)
+
+    def _raise_if_not_observable(self):
+        # Functions that mutate the state of the metric, for example incrementing
+        # a counter, will fail if the metric is not observable, because only if a
+        # metric is observable will the value be initialized.
+        if not self._is_observable():
+            raise ValueError('%s metric is missing label values' % str(self._type))
+
+    def _is_parent(self):
+        return self._labelnames and not self._labelvalues
+
+    def _get_metric(self):
+        return Metric(self._name, self._documentation, self._type, self._unit)
+
+    def describe(self) -> Iterable[Metric]:
+        return [self._get_metric()]
+
+    def collect(self) -> Iterable[Metric]:
+        metric = self._get_metric()
+        for suffix, labels, value, timestamp, exemplar in self._samples():
+            metric.add_sample(self._name + suffix, labels, value, timestamp, exemplar)
+        return [metric]
+
+    def __str__(self) -> str:
+        return f"{self._type}:{self._name}"
+
+    def __repr__(self) -> str:
+        metric_type = type(self)
+        return f"{metric_type.__module__}.{metric_type.__name__}({self._name})"
+
+    def __init__(self: T,
+                 name: str,
+                 documentation: str,
+                 labelnames: Iterable[str] = (),
+                 namespace: str = '',
+                 subsystem: str = '',
+                 unit: str = '',
+                 registry: Optional[CollectorRegistry] = REGISTRY,
+                 _labelvalues: Optional[Sequence[str]] = None,
+                 ) -> None:
+        self._name = _build_full_name(self._type, name, namespace, subsystem, unit)
+        self._labelnames = _validate_labelnames(self, labelnames)
+        self._labelvalues = tuple(_labelvalues or ())
+        self._kwargs: Dict[str, Any] = {}
+        self._documentation = documentation
+        self._unit = unit
+
+        if not METRIC_NAME_RE.match(self._name):
+            raise ValueError('Invalid metric name: ' + self._name)
+
+        if self._is_parent():
+            # Prepare the fields needed for child metrics.
+            self._lock = Lock()
+            self._metrics: Dict[Sequence[str], T] = {}
+
+        if self._is_observable():
+            self._metric_init()
+
+        if not self._labelvalues:
+            # Register the multi-wrapper parent metric, or if a label-less metric, the whole shebang.
+            if registry:
+                registry.register(self)
+
+    def labels(self: T, *labelvalues: Any, **labelkwargs: Any) -> T:
+        """Return the child for the given labelset.
+
+        All metrics can have labels, allowing grouping of related time series.
+        Taking a counter as an example:
+
+            from prometheus_client import Counter
+
+            c = Counter('my_requests_total', 'HTTP Failures', ['method', 'endpoint'])
+            c.labels('get', '/').inc()
+            c.labels('post', '/submit').inc()
+
+        Labels can also be provided as keyword arguments:
+
+            from prometheus_client import Counter
+
+            c = Counter('my_requests_total', 'HTTP Failures', ['method', 'endpoint'])
+            c.labels(method='get', endpoint='/').inc()
+            c.labels(method='post', endpoint='/submit').inc()
+
+        See the best practices on [naming](http://prometheus.io/docs/practices/naming/)
+        and [labels](http://prometheus.io/docs/practices/instrumentation/#use-labels).
+        """
+        if not self._labelnames:
+            raise ValueError('No label names were set when constructing %s' % self)
+
+        if self._labelvalues:
+            raise ValueError('{} already has labels set ({}); can not chain calls to .labels()'.format(
+                self,
+                dict(zip(self._labelnames, self._labelvalues))
+            ))
+
+        if labelvalues and labelkwargs:
+            raise ValueError("Can't pass both *args and **kwargs")
+
+        if labelkwargs:
+            if sorted(labelkwargs) != sorted(self._labelnames):
+                raise ValueError('Incorrect label names')
+            labelvalues = tuple(str(labelkwargs[l]) for l in self._labelnames)
+        else:
+            if len(labelvalues) != len(self._labelnames):
+                raise ValueError('Incorrect label count')
+            labelvalues = tuple(str(l) for l in labelvalues)
+        with self._lock:
+            if labelvalues not in self._metrics:
+                self._metrics[labelvalues] = self.__class__(
+                    self._name,
+                    documentation=self._documentation,
+                    labelnames=self._labelnames,
+                    unit=self._unit,
+                    _labelvalues=labelvalues,
+                    **self._kwargs
+                )
+            return self._metrics[labelvalues]
+
+    def remove(self, *labelvalues: Any) -> None:
+        if 'prometheus_multiproc_dir' in os.environ or 'PROMETHEUS_MULTIPROC_DIR' in os.environ:
+            warnings.warn(
+                "Removal of labels has not been implemented in  multi-process mode yet.",
+                UserWarning)
+
+        if not self._labelnames:
+            raise ValueError('No label names were set when constructing %s' % self)
+
+        """Remove the given labelset from the metric."""
+        if len(labelvalues) != len(self._labelnames):
+            raise ValueError('Incorrect label count (expected %d, got %s)' % (len(self._labelnames), labelvalues))
+        labelvalues = tuple(str(l) for l in labelvalues)
+        with self._lock:
+            del self._metrics[labelvalues]
+
+    def clear(self) -> None:
+        """Remove all labelsets from the metric"""
+        if 'prometheus_multiproc_dir' in os.environ or 'PROMETHEUS_MULTIPROC_DIR' in os.environ:
+            warnings.warn(
+                "Clearing labels has not been implemented in multi-process mode yet",
+                UserWarning)
+        with self._lock:
+            self._metrics = {}
+
+    def _samples(self) -> Iterable[Sample]:
+        if self._is_parent():
+            return self._multi_samples()
+        else:
+            return self._child_samples()
+
+    def _multi_samples(self) -> Iterable[Sample]:
+        with self._lock:
+            metrics = self._metrics.copy()
+        for labels, metric in metrics.items():
+            series_labels = list(zip(self._labelnames, labels))
+            for suffix, sample_labels, value, timestamp, exemplar in metric._samples():
+                yield Sample(suffix, dict(series_labels + list(sample_labels.items())), value, timestamp, exemplar)
+
+    def _child_samples(self) -> Iterable[Sample]:  # pragma: no cover
+        raise NotImplementedError('_child_samples() must be implemented by %r' % self)
+
+    def _metric_init(self):  # pragma: no cover
+        """
+        Initialize the metric object as a child, i.e. when it has labels (if any) set.
+
+        This is factored as a separate function to allow for deferred initialization.
+        """
+        raise NotImplementedError('_metric_init() must be implemented by %r' % self)
+
+
+class Counter(MetricWrapperBase):
+    """A Counter tracks counts of events or running totals.
+
+    Example use cases for Counters:
+    - Number of requests processed
+    - Number of items that were inserted into a queue
+    - Total amount of data that a system has processed
+
+    Counters can only go up (and be reset when the process restarts). If your use case can go down,
+    you should use a Gauge instead.
+
+    An example for a Counter:
+
+        from prometheus_client import Counter
+
+        c = Counter('my_failures_total', 'Description of counter')
+        c.inc()     # Increment by 1
+        c.inc(1.6)  # Increment by given value
+
+    There are utilities to count exceptions raised:
+
+        @c.count_exceptions()
+        def f():
+            pass
+
+        with c.count_exceptions():
+            pass
+
+        # Count only one type of exception
+        with c.count_exceptions(ValueError):
+            pass
+            
+    You can also reset the counter to zero in case your logical "process" restarts
+    without restarting the actual python process.
+
+       c.reset()
+
+    """
+    _type = 'counter'
+
+    def _metric_init(self) -> None:
+        self._value = values.ValueClass(self._type, self._name, self._name + '_total', self._labelnames,
+                                        self._labelvalues, self._documentation)
+        self._created = time.time()
+
+    def inc(self, amount: float = 1, exemplar: Optional[Dict[str, str]] = None) -> None:
+        """Increment counter by the given amount."""
+        self._raise_if_not_observable()
+        if amount < 0:
+            raise ValueError('Counters can only be incremented by non-negative amounts.')
+        self._value.inc(amount)
+        if exemplar:
+            _validate_exemplar(exemplar)
+            self._value.set_exemplar(Exemplar(exemplar, amount, time.time()))
+
+    def reset(self) -> None:
+        """Reset the counter to zero. Use this when a logical process restarts without restarting the actual python process."""
+        self._value.set(0)
+        self._created = time.time()
+
+    def count_exceptions(self, exception: Union[Type[BaseException], Tuple[Type[BaseException], ...]] = Exception) -> ExceptionCounter:
+        """Count exceptions in a block of code or function.
+
+        Can be used as a function decorator or context manager.
+        Increments the counter when an exception of the given
+        type is raised up out of the code.
+        """
+        self._raise_if_not_observable()
+        return ExceptionCounter(self, exception)
+
+    def _child_samples(self) -> Iterable[Sample]:
+        sample = Sample('_total', {}, self._value.get(), None, self._value.get_exemplar())
+        if _use_created:
+            return (
+                sample,
+                Sample('_created', {}, self._created, None, None)
+            )
+        return (sample,)
+
+
+class Gauge(MetricWrapperBase):
+    """Gauge metric, to report instantaneous values.
+
+     Examples of Gauges include:
+        - Inprogress requests
+        - Number of items in a queue
+        - Free memory
+        - Total memory
+        - Temperature
+
+     Gauges can go both up and down.
+
+        from prometheus_client import Gauge
+
+        g = Gauge('my_inprogress_requests', 'Description of gauge')
+        g.inc()      # Increment by 1
+        g.dec(10)    # Decrement by given value
+        g.set(4.2)   # Set to a given value
+
+     There are utilities for common use cases:
+
+        g.set_to_current_time()   # Set to current unixtime
+
+        # Increment when entered, decrement when exited.
+        @g.track_inprogress()
+        def f():
+            pass
+
+        with g.track_inprogress():
+            pass
+
+     A Gauge can also take its value from a callback:
+
+        d = Gauge('data_objects', 'Number of objects')
+        my_dict = {}
+        d.set_function(lambda: len(my_dict))
+    """
+    _type = 'gauge'
+    _MULTIPROC_MODES = frozenset(('all', 'liveall', 'min', 'livemin', 'max', 'livemax', 'sum', 'livesum', 'mostrecent', 'livemostrecent'))
+    _MOST_RECENT_MODES = frozenset(('mostrecent', 'livemostrecent'))
+
+    def __init__(self,
+                 name: str,
+                 documentation: str,
+                 labelnames: Iterable[str] = (),
+                 namespace: str = '',
+                 subsystem: str = '',
+                 unit: str = '',
+                 registry: Optional[CollectorRegistry] = REGISTRY,
+                 _labelvalues: Optional[Sequence[str]] = None,
+                 multiprocess_mode: Literal['all', 'liveall', 'min', 'livemin', 'max', 'livemax', 'sum', 'livesum', 'mostrecent', 'livemostrecent'] = 'all',
+                 ):
+        self._multiprocess_mode = multiprocess_mode
+        if multiprocess_mode not in self._MULTIPROC_MODES:
+            raise ValueError('Invalid multiprocess mode: ' + multiprocess_mode)
+        super().__init__(
+            name=name,
+            documentation=documentation,
+            labelnames=labelnames,
+            namespace=namespace,
+            subsystem=subsystem,
+            unit=unit,
+            registry=registry,
+            _labelvalues=_labelvalues,
+        )
+        self._kwargs['multiprocess_mode'] = self._multiprocess_mode
+        self._is_most_recent = self._multiprocess_mode in self._MOST_RECENT_MODES
+
+    def _metric_init(self) -> None:
+        self._value = values.ValueClass(
+            self._type, self._name, self._name, self._labelnames, self._labelvalues,
+            self._documentation, multiprocess_mode=self._multiprocess_mode
+        )
+
+    def inc(self, amount: float = 1) -> None:
+        """Increment gauge by the given amount."""
+        if self._is_most_recent:
+            raise RuntimeError("inc must not be used with the mostrecent mode")
+        self._raise_if_not_observable()
+        self._value.inc(amount)
+
+    def dec(self, amount: float = 1) -> None:
+        """Decrement gauge by the given amount."""
+        if self._is_most_recent:
+            raise RuntimeError("dec must not be used with the mostrecent mode")
+        self._raise_if_not_observable()
+        self._value.inc(-amount)
+
+    def set(self, value: float) -> None:
+        """Set gauge to the given value."""
+        self._raise_if_not_observable()
+        if self._is_most_recent:
+            self._value.set(float(value), timestamp=time.time())
+        else:
+            self._value.set(float(value))
+
+    def set_to_current_time(self) -> None:
+        """Set gauge to the current unixtime."""
+        self.set(time.time())
+
+    def track_inprogress(self) -> InprogressTracker:
+        """Track inprogress blocks of code or functions.
+
+        Can be used as a function decorator or context manager.
+        Increments the gauge when the code is entered,
+        and decrements when it is exited.
+        """
+        self._raise_if_not_observable()
+        return InprogressTracker(self)
+
+    def time(self) -> Timer:
+        """Time a block of code or function, and set the duration in seconds.
+
+        Can be used as a function decorator or context manager.
+        """
+        return Timer(self, 'set')
+
+    def set_function(self, f: Callable[[], float]) -> None:
+        """Call the provided function to return the Gauge value.
+
+        The function must return a float, and may be called from
+        multiple threads. All other methods of the Gauge become NOOPs.
+        """
+
+        self._raise_if_not_observable()
+
+        def samples(_: Gauge) -> Iterable[Sample]:
+            return (Sample('', {}, float(f()), None, None),)
+
+        self._child_samples = types.MethodType(samples, self)  # type: ignore
+
+    def _child_samples(self) -> Iterable[Sample]:
+        return (Sample('', {}, self._value.get(), None, None),)
+
+
+class Summary(MetricWrapperBase):
+    """A Summary tracks the size and number of events.
+
+    Example use cases for Summaries:
+    - Response latency
+    - Request size
+
+    Example for a Summary:
+
+        from prometheus_client import Summary
+
+        s = Summary('request_size_bytes', 'Request size (bytes)')
+        s.observe(512)  # Observe 512 (bytes)
+
+    Example for a Summary using time:
+
+        from prometheus_client import Summary
+
+        REQUEST_TIME = Summary('response_latency_seconds', 'Response latency (seconds)')
+
+        @REQUEST_TIME.time()
+        def create_response(request):
+          '''A dummy function'''
+          time.sleep(1)
+
+    Example for using the same Summary object as a context manager:
+
+        with REQUEST_TIME.time():
+            pass  # Logic to be timed
+    """
+    _type = 'summary'
+    _reserved_labelnames = ['quantile']
+
+    def _metric_init(self) -> None:
+        self._count = values.ValueClass(self._type, self._name, self._name + '_count', self._labelnames,
+                                        self._labelvalues, self._documentation)
+        self._sum = values.ValueClass(self._type, self._name, self._name + '_sum', self._labelnames, self._labelvalues, self._documentation)
+        self._created = time.time()
+
+    def observe(self, amount: float) -> None:
+        """Observe the given amount.
+
+        The amount is usually positive or zero. Negative values are
+        accepted but prevent current versions of Prometheus from
+        properly detecting counter resets in the sum of
+        observations. See
+        https://prometheus.io/docs/practices/histograms/#count-and-sum-of-observations
+        for details.
+        """
+        self._raise_if_not_observable()
+        self._count.inc(1)
+        self._sum.inc(amount)
+
+    def time(self) -> Timer:
+        """Time a block of code or function, and observe the duration in seconds.
+
+        Can be used as a function decorator or context manager.
+        """
+        return Timer(self, 'observe')
+
+    def _child_samples(self) -> Iterable[Sample]:
+        samples = [
+            Sample('_count', {}, self._count.get(), None, None),
+            Sample('_sum', {}, self._sum.get(), None, None),
+        ]
+        if _use_created:
+            samples.append(Sample('_created', {}, self._created, None, None))
+        return tuple(samples)
+
+
+class Histogram(MetricWrapperBase):
+    """A Histogram tracks the size and number of events in buckets.
+
+    You can use Histograms for aggregatable calculation of quantiles.
+
+    Example use cases:
+    - Response latency
+    - Request size
+
+    Example for a Histogram:
+
+        from prometheus_client import Histogram
+
+        h = Histogram('request_size_bytes', 'Request size (bytes)')
+        h.observe(512)  # Observe 512 (bytes)
+
+    Example for a Histogram using time:
+
+        from prometheus_client import Histogram
+
+        REQUEST_TIME = Histogram('response_latency_seconds', 'Response latency (seconds)')
+
+        @REQUEST_TIME.time()
+        def create_response(request):
+          '''A dummy function'''
+          time.sleep(1)
+
+    Example of using the same Histogram object as a context manager:
+
+        with REQUEST_TIME.time():
+            pass  # Logic to be timed
+
+    The default buckets are intended to cover a typical web/rpc request from milliseconds to seconds.
+    They can be overridden by passing `buckets` keyword argument to `Histogram`.
+    """
+    _type = 'histogram'
+    _reserved_labelnames = ['le']
+    DEFAULT_BUCKETS = (.005, .01, .025, .05, .075, .1, .25, .5, .75, 1.0, 2.5, 5.0, 7.5, 10.0, INF)
+
+    def __init__(self,
+                 name: str,
+                 documentation: str,
+                 labelnames: Iterable[str] = (),
+                 namespace: str = '',
+                 subsystem: str = '',
+                 unit: str = '',
+                 registry: Optional[CollectorRegistry] = REGISTRY,
+                 _labelvalues: Optional[Sequence[str]] = None,
+                 buckets: Sequence[Union[float, str]] = DEFAULT_BUCKETS,
+                 ):
+        self._prepare_buckets(buckets)
+        super().__init__(
+            name=name,
+            documentation=documentation,
+            labelnames=labelnames,
+            namespace=namespace,
+            subsystem=subsystem,
+            unit=unit,
+            registry=registry,
+            _labelvalues=_labelvalues,
+        )
+        self._kwargs['buckets'] = buckets
+
+    def _prepare_buckets(self, source_buckets: Sequence[Union[float, str]]) -> None:
+        buckets = [float(b) for b in source_buckets]
+        if buckets != sorted(buckets):
+            # This is probably an error on the part of the user,
+            # so raise rather than sorting for them.
+            raise ValueError('Buckets not in sorted order')
+        if buckets and buckets[-1] != INF:
+            buckets.append(INF)
+        if len(buckets) < 2:
+            raise ValueError('Must have at least two buckets')
+        self._upper_bounds = buckets
+
+    def _metric_init(self) -> None:
+        self._buckets: List[values.ValueClass] = []
+        self._created = time.time()
+        bucket_labelnames = self._labelnames + ('le',)
+        self._sum = values.ValueClass(self._type, self._name, self._name + '_sum', self._labelnames, self._labelvalues, self._documentation)
+        for b in self._upper_bounds:
+            self._buckets.append(values.ValueClass(
+                self._type,
+                self._name,
+                self._name + '_bucket',
+                bucket_labelnames,
+                self._labelvalues + (floatToGoString(b),),
+                self._documentation)
+            )
+
+    def observe(self, amount: float, exemplar: Optional[Dict[str, str]] = None) -> None:
+        """Observe the given amount.
+
+        The amount is usually positive or zero. Negative values are
+        accepted but prevent current versions of Prometheus from
+        properly detecting counter resets in the sum of
+        observations. See
+        https://prometheus.io/docs/practices/histograms/#count-and-sum-of-observations
+        for details.
+        """
+        self._raise_if_not_observable()
+        self._sum.inc(amount)
+        for i, bound in enumerate(self._upper_bounds):
+            if amount <= bound:
+                self._buckets[i].inc(1)
+                if exemplar:
+                    _validate_exemplar(exemplar)
+                    self._buckets[i].set_exemplar(Exemplar(exemplar, amount, time.time()))
+                break
+
+    def time(self) -> Timer:
+        """Time a block of code or function, and observe the duration in seconds.
+
+        Can be used as a function decorator or context manager.
+        """
+        return Timer(self, 'observe')
+
+    def _child_samples(self) -> Iterable[Sample]:
+        samples = []
+        acc = 0.0
+        for i, bound in enumerate(self._upper_bounds):
+            acc += self._buckets[i].get()
+            samples.append(Sample('_bucket', {'le': floatToGoString(bound)}, acc, None, self._buckets[i].get_exemplar()))
+        samples.append(Sample('_count', {}, acc, None, None))
+        if self._upper_bounds[0] >= 0:
+            samples.append(Sample('_sum', {}, self._sum.get(), None, None))
+        if _use_created:
+            samples.append(Sample('_created', {}, self._created, None, None))
+        return tuple(samples)
+
+
+class Info(MetricWrapperBase):
+    """Info metric, key-value pairs.
+
+     Examples of Info include:
+        - Build information
+        - Version information
+        - Potential target metadata
+
+     Example usage:
+        from prometheus_client import Info
+
+        i = Info('my_build', 'Description of info')
+        i.info({'version': '1.2.3', 'buildhost': 'foo@bar'})
+
+     Info metrics do not work in multiprocess mode.
+    """
+    _type = 'info'
+
+    def _metric_init(self):
+        self._labelname_set = set(self._labelnames)
+        self._lock = Lock()
+        self._value = {}
+
+    def info(self, val: Dict[str, str]) -> None:
+        """Set info metric."""
+        if self._labelname_set.intersection(val.keys()):
+            raise ValueError('Overlapping labels for Info metric, metric: {} child: {}'.format(
+                self._labelnames, val))
+        if any(i is None for i in val.values()):
+            raise ValueError('Label value cannot be None')
+        with self._lock:
+            self._value = dict(val)
+
+    def _child_samples(self) -> Iterable[Sample]:
+        with self._lock:
+            return (Sample('_info', self._value, 1.0, None, None),)
+
+
+class Enum(MetricWrapperBase):
+    """Enum metric, which of a set of states is true.
+
+     Example usage:
+        from prometheus_client import Enum
+
+        e = Enum('task_state', 'Description of enum',
+          states=['starting', 'running', 'stopped'])
+        e.state('running')
+
+     The first listed state will be the default.
+     Enum metrics do not work in multiprocess mode.
+    """
+    _type = 'stateset'
+
+    def __init__(self,
+                 name: str,
+                 documentation: str,
+                 labelnames: Sequence[str] = (),
+                 namespace: str = '',
+                 subsystem: str = '',
+                 unit: str = '',
+                 registry: Optional[CollectorRegistry] = REGISTRY,
+                 _labelvalues: Optional[Sequence[str]] = None,
+                 states: Optional[Sequence[str]] = None,
+                 ):
+        super().__init__(
+            name=name,
+            documentation=documentation,
+            labelnames=labelnames,
+            namespace=namespace,
+            subsystem=subsystem,
+            unit=unit,
+            registry=registry,
+            _labelvalues=_labelvalues,
+        )
+        if name in labelnames:
+            raise ValueError(f'Overlapping labels for Enum metric: {name}')
+        if not states:
+            raise ValueError(f'No states provided for Enum metric: {name}')
+        self._kwargs['states'] = self._states = states
+
+    def _metric_init(self) -> None:
+        self._value = 0
+        self._lock = Lock()
+
+    def state(self, state: str) -> None:
+        """Set enum metric state."""
+        self._raise_if_not_observable()
+        with self._lock:
+            self._value = self._states.index(state)
+
+    def _child_samples(self) -> Iterable[Sample]:
+        with self._lock:
+            return [
+                Sample('', {self._name: s}, 1 if i == self._value else 0, None, None)
+                for i, s
+                in enumerate(self._states)
+            ]
diff --git a/zhmc_prometheus_exporter/vendor/prometheus_client/metrics_core.py b/zhmc_prometheus_exporter/vendor/prometheus_client/metrics_core.py
new file mode 100644
index 00000000..7226d920
--- /dev/null
+++ b/zhmc_prometheus_exporter/vendor/prometheus_client/metrics_core.py
@@ -0,0 +1,418 @@
+import re
+from typing import Dict, List, Optional, Sequence, Tuple, Union
+
+from .samples import Exemplar, Sample, Timestamp
+
+METRIC_TYPES = (
+    'counter', 'gauge', 'summary', 'histogram',
+    'gaugehistogram', 'unknown', 'info', 'stateset',
+)
+METRIC_NAME_RE = re.compile(r'^[a-zA-Z_:][a-zA-Z0-9_:]*$')
+METRIC_LABEL_NAME_RE = re.compile(r'^[a-zA-Z_][a-zA-Z0-9_]*$')
+RESERVED_METRIC_LABEL_NAME_RE = re.compile(r'^__.*$')
+
+
+class Metric:
+    """A single metric family and its samples.
+
+    This is intended only for internal use by the instrumentation client.
+
+    Custom collectors should use GaugeMetricFamily, CounterMetricFamily
+    and SummaryMetricFamily instead.
+    """
+
+    def __init__(self, name: str, documentation: str, typ: str, unit: str = ''):
+        if unit and not name.endswith("_" + unit):
+            name += "_" + unit
+        if not METRIC_NAME_RE.match(name):
+            raise ValueError('Invalid metric name: ' + name)
+        self.name: str = name
+        self.documentation: str = documentation
+        self.unit: str = unit
+        if typ == 'untyped':
+            typ = 'unknown'
+        if typ not in METRIC_TYPES:
+            raise ValueError('Invalid metric type: ' + typ)
+        self.type: str = typ
+        self.samples: List[Sample] = []
+
+    def add_sample(self, name: str, labels: Dict[str, str], value: float, timestamp: Optional[Union[Timestamp, float]] = None, exemplar: Optional[Exemplar] = None) -> None:
+        """Add a sample to the metric.
+
+        Internal-only, do not use."""
+        self.samples.append(Sample(name, labels, value, timestamp, exemplar))
+
+    def __eq__(self, other: object) -> bool:
+        return (isinstance(other, Metric)
+                and self.name == other.name
+                and self.documentation == other.documentation
+                and self.type == other.type
+                and self.unit == other.unit
+                and self.samples == other.samples)
+
+    def __repr__(self) -> str:
+        return "Metric({}, {}, {}, {}, {})".format(
+            self.name,
+            self.documentation,
+            self.type,
+            self.unit,
+            self.samples,
+        )
+
+    def _restricted_metric(self, names):
+        """Build a snapshot of a metric with samples restricted to a given set of names."""
+        samples = [s for s in self.samples if s[0] in names]
+        if samples:
+            m = Metric(self.name, self.documentation, self.type)
+            m.samples = samples
+            return m
+        return None
+
+
+class UnknownMetricFamily(Metric):
+    """A single unknown metric and its samples.
+    For use by custom collectors.
+    """
+
+    def __init__(self,
+                 name: str,
+                 documentation: str,
+                 value: Optional[float] = None,
+                 labels: Optional[Sequence[str]] = None,
+                 unit: str = '',
+                 ):
+        Metric.__init__(self, name, documentation, 'unknown', unit)
+        if labels is not None and value is not None:
+            raise ValueError('Can only specify at most one of value and labels.')
+        if labels is None:
+            labels = []
+        self._labelnames = tuple(labels)
+        if value is not None:
+            self.add_metric([], value)
+
+    def add_metric(self, labels: Sequence[str], value: float, timestamp: Optional[Union[Timestamp, float]] = None) -> None:
+        """Add a metric to the metric family.
+        Args:
+        labels: A list of label values
+        value: The value of the metric.
+        """
+        self.samples.append(Sample(self.name, dict(zip(self._labelnames, labels)), value, timestamp))
+
+
+# For backward compatibility.
+UntypedMetricFamily = UnknownMetricFamily
+
+
+class CounterMetricFamily(Metric):
+    """A single counter and its samples.
+
+    For use by custom collectors.
+    """
+
+    def __init__(self,
+                 name: str,
+                 documentation: str,
+                 value: Optional[float] = None,
+                 labels: Optional[Sequence[str]] = None,
+                 created: Optional[float] = None,
+                 unit: str = '',
+                 ):
+        # Glue code for pre-OpenMetrics metrics.
+        if name.endswith('_total'):
+            name = name[:-6]
+        Metric.__init__(self, name, documentation, 'counter', unit)
+        if labels is not None and value is not None:
+            raise ValueError('Can only specify at most one of value and labels.')
+        if labels is None:
+            labels = []
+        self._labelnames = tuple(labels)
+        if value is not None:
+            self.add_metric([], value, created)
+
+    def add_metric(self,
+                   labels: Sequence[str],
+                   value: float,
+                   created: Optional[float] = None,
+                   timestamp: Optional[Union[Timestamp, float]] = None,
+                   ) -> None:
+        """Add a metric to the metric family.
+
+        Args:
+          labels: A list of label values
+          value: The value of the metric
+          created: Optional unix timestamp the child was created at.
+        """
+        self.samples.append(Sample(self.name + '_total', dict(zip(self._labelnames, labels)), value, timestamp))
+        if created is not None:
+            self.samples.append(Sample(self.name + '_created', dict(zip(self._labelnames, labels)), created, timestamp))
+
+
+class GaugeMetricFamily(Metric):
+    """A single gauge and its samples.
+
+    For use by custom collectors.
+    """
+
+    def __init__(self,
+                 name: str,
+                 documentation: str,
+                 value: Optional[float] = None,
+                 labels: Optional[Sequence[str]] = None,
+                 unit: str = '',
+                 ):
+        Metric.__init__(self, name, documentation, 'gauge', unit)
+        if labels is not None and value is not None:
+            raise ValueError('Can only specify at most one of value and labels.')
+        if labels is None:
+            labels = []
+        self._labelnames = tuple(labels)
+        if value is not None:
+            self.add_metric([], value)
+
+    def add_metric(self, labels: Sequence[str], value: float, timestamp: Optional[Union[Timestamp, float]] = None) -> None:
+        """Add a metric to the metric family.
+
+        Args:
+          labels: A list of label values
+          value: A float
+        """
+        self.samples.append(Sample(self.name, dict(zip(self._labelnames, labels)), value, timestamp))
+
+
+class SummaryMetricFamily(Metric):
+    """A single summary and its samples.
+
+    For use by custom collectors.
+    """
+
+    def __init__(self,
+                 name: str,
+                 documentation: str,
+                 count_value: Optional[int] = None,
+                 sum_value: Optional[float] = None,
+                 labels: Optional[Sequence[str]] = None,
+                 unit: str = '',
+                 ):
+        Metric.__init__(self, name, documentation, 'summary', unit)
+        if (sum_value is None) != (count_value is None):
+            raise ValueError('count_value and sum_value must be provided together.')
+        if labels is not None and count_value is not None:
+            raise ValueError('Can only specify at most one of value and labels.')
+        if labels is None:
+            labels = []
+        self._labelnames = tuple(labels)
+        # The and clause is necessary only for typing, the above ValueError will raise if only one is set.
+        if count_value is not None and sum_value is not None:
+            self.add_metric([], count_value, sum_value)
+
+    def add_metric(self,
+                   labels: Sequence[str],
+                   count_value: int,
+                   sum_value: float,
+                   timestamp:
+                   Optional[Union[float, Timestamp]] = None
+                   ) -> None:
+        """Add a metric to the metric family.
+
+        Args:
+          labels: A list of label values
+          count_value: The count value of the metric.
+          sum_value: The sum value of the metric.
+        """
+        self.samples.append(Sample(self.name + '_count', dict(zip(self._labelnames, labels)), count_value, timestamp))
+        self.samples.append(Sample(self.name + '_sum', dict(zip(self._labelnames, labels)), sum_value, timestamp))
+
+
+class HistogramMetricFamily(Metric):
+    """A single histogram and its samples.
+
+    For use by custom collectors.
+    """
+
+    def __init__(self,
+                 name: str,
+                 documentation: str,
+                 buckets: Optional[Sequence[Union[Tuple[str, float], Tuple[str, float, Exemplar]]]] = None,
+                 sum_value: Optional[float] = None,
+                 labels: Optional[Sequence[str]] = None,
+                 unit: str = '',
+                 ):
+        Metric.__init__(self, name, documentation, 'histogram', unit)
+        if sum_value is not None and buckets is None:
+            raise ValueError('sum value cannot be provided without buckets.')
+        if labels is not None and buckets is not None:
+            raise ValueError('Can only specify at most one of buckets and labels.')
+        if labels is None:
+            labels = []
+        self._labelnames = tuple(labels)
+        if buckets is not None:
+            self.add_metric([], buckets, sum_value)
+
+    def add_metric(self,
+                   labels: Sequence[str],
+                   buckets: Sequence[Union[Tuple[str, float], Tuple[str, float, Exemplar]]],
+                   sum_value: Optional[float],
+                   timestamp: Optional[Union[Timestamp, float]] = None) -> None:
+        """Add a metric to the metric family.
+
+        Args:
+          labels: A list of label values
+          buckets: A list of lists.
+              Each inner list can be a pair of bucket name and value,
+              or a triple of bucket name, value, and exemplar.
+              The buckets must be sorted, and +Inf present.
+          sum_value: The sum value of the metric.
+        """
+        for b in buckets:
+            bucket, value = b[:2]
+            exemplar = None
+            if len(b) == 3:
+                exemplar = b[2]  # type: ignore
+            self.samples.append(Sample(
+                self.name + '_bucket',
+                dict(list(zip(self._labelnames, labels)) + [('le', bucket)]),
+                value,
+                timestamp,
+                exemplar,
+            ))
+        # Don't include sum and thus count if there's negative buckets.
+        if float(buckets[0][0]) >= 0 and sum_value is not None:
+            # +Inf is last and provides the count value.
+            self.samples.append(
+                Sample(self.name + '_count', dict(zip(self._labelnames, labels)), buckets[-1][1], timestamp))
+            self.samples.append(
+                Sample(self.name + '_sum', dict(zip(self._labelnames, labels)), sum_value, timestamp))
+
+
+
+class GaugeHistogramMetricFamily(Metric):
+    """A single gauge histogram and its samples.
+
+    For use by custom collectors.
+    """
+
+    def __init__(self,
+                 name: str,
+                 documentation: str,
+                 buckets: Optional[Sequence[Tuple[str, float]]] = None,
+                 gsum_value: Optional[float] = None,
+                 labels: Optional[Sequence[str]] = None,
+                 unit: str = '',
+                 ):
+        Metric.__init__(self, name, documentation, 'gaugehistogram', unit)
+        if labels is not None and buckets is not None:
+            raise ValueError('Can only specify at most one of buckets and labels.')
+        if labels is None:
+            labels = []
+        self._labelnames = tuple(labels)
+        if buckets is not None:
+            self.add_metric([], buckets, gsum_value)
+
+    def add_metric(self,
+                   labels: Sequence[str],
+                   buckets: Sequence[Tuple[str, float]],
+                   gsum_value: Optional[float],
+                   timestamp: Optional[Union[float, Timestamp]] = None,
+                   ) -> None:
+        """Add a metric to the metric family.
+
+        Args:
+          labels: A list of label values
+          buckets: A list of pairs of bucket names and values.
+              The buckets must be sorted, and +Inf present.
+          gsum_value: The sum value of the metric.
+        """
+        for bucket, value in buckets:
+            self.samples.append(Sample(
+                self.name + '_bucket',
+                dict(list(zip(self._labelnames, labels)) + [('le', bucket)]),
+                value, timestamp))
+        # +Inf is last and provides the count value.
+        self.samples.extend([
+            Sample(self.name + '_gcount', dict(zip(self._labelnames, labels)), buckets[-1][1], timestamp),
+            # TODO: Handle None gsum_value correctly. Currently a None will fail exposition but is allowed here.
+            Sample(self.name + '_gsum', dict(zip(self._labelnames, labels)), gsum_value, timestamp),  # type: ignore
+        ])
+
+
+class InfoMetricFamily(Metric):
+    """A single info and its samples.
+
+    For use by custom collectors.
+    """
+
+    def __init__(self,
+                 name: str,
+                 documentation: str,
+                 value: Optional[Dict[str, str]] = None,
+                 labels: Optional[Sequence[str]] = None,
+                 ):
+        Metric.__init__(self, name, documentation, 'info')
+        if labels is not None and value is not None:
+            raise ValueError('Can only specify at most one of value and labels.')
+        if labels is None:
+            labels = []
+        self._labelnames = tuple(labels)
+        if value is not None:
+            self.add_metric([], value)
+
+    def add_metric(self,
+                   labels: Sequence[str],
+                   value: Dict[str, str],
+                   timestamp: Optional[Union[Timestamp, float]] = None,
+                   ) -> None:
+        """Add a metric to the metric family.
+
+        Args:
+          labels: A list of label values
+          value: A dict of labels
+        """
+        self.samples.append(Sample(
+            self.name + '_info',
+            dict(dict(zip(self._labelnames, labels)), **value),
+            1,
+            timestamp,
+        ))
+
+
+class StateSetMetricFamily(Metric):
+    """A single stateset and its samples.
+
+    For use by custom collectors.
+    """
+
+    def __init__(self,
+                 name: str,
+                 documentation: str,
+                 value: Optional[Dict[str, bool]] = None,
+                 labels: Optional[Sequence[str]] = None,
+                 ):
+        Metric.__init__(self, name, documentation, 'stateset')
+        if labels is not None and value is not None:
+            raise ValueError('Can only specify at most one of value and labels.')
+        if labels is None:
+            labels = []
+        self._labelnames = tuple(labels)
+        if value is not None:
+            self.add_metric([], value)
+
+    def add_metric(self,
+                   labels: Sequence[str],
+                   value: Dict[str, bool],
+                   timestamp: Optional[Union[Timestamp, float]] = None,
+                   ) -> None:
+        """Add a metric to the metric family.
+
+        Args:
+          labels: A list of label values
+          value: A dict of string state names to booleans
+        """
+        labels = tuple(labels)
+        for state, enabled in sorted(value.items()):
+            v = (1 if enabled else 0)
+            self.samples.append(Sample(
+                self.name,
+                dict(zip(self._labelnames + (self.name,), labels + (state,))),
+                v,
+                timestamp,
+            ))
diff --git a/zhmc_prometheus_exporter/vendor/prometheus_client/mmap_dict.py b/zhmc_prometheus_exporter/vendor/prometheus_client/mmap_dict.py
new file mode 100644
index 00000000..edd895cd
--- /dev/null
+++ b/zhmc_prometheus_exporter/vendor/prometheus_client/mmap_dict.py
@@ -0,0 +1,145 @@
+import json
+import mmap
+import os
+import struct
+from typing import List
+
+_INITIAL_MMAP_SIZE = 1 << 16
+_pack_integer_func = struct.Struct(b'i').pack
+_pack_two_doubles_func = struct.Struct(b'dd').pack
+_unpack_integer = struct.Struct(b'i').unpack_from
+_unpack_two_doubles = struct.Struct(b'dd').unpack_from
+
+
+# struct.pack_into has atomicity issues because it will temporarily write 0 into
+# the mmap, resulting in false reads to 0 when experiencing a lot of writes.
+# Using direct assignment solves this issue.
+
+
+def _pack_two_doubles(data, pos, value, timestamp):
+    data[pos:pos + 16] = _pack_two_doubles_func(value, timestamp)
+
+
+def _pack_integer(data, pos, value):
+    data[pos:pos + 4] = _pack_integer_func(value)
+
+
+def _read_all_values(data, used=0):
+    """Yield (key, value, timestamp, pos). No locking is performed."""
+
+    if used <= 0:
+        # If not valid `used` value is passed in, read it from the file.
+        used = _unpack_integer(data, 0)[0]
+
+    pos = 8
+
+    while pos < used:
+        encoded_len = _unpack_integer(data, pos)[0]
+        # check we are not reading beyond bounds
+        if encoded_len + pos > used:
+            raise RuntimeError('Read beyond file size detected, file is corrupted.')
+        pos += 4
+        encoded_key = data[pos:pos + encoded_len]
+        padded_len = encoded_len + (8 - (encoded_len + 4) % 8)
+        pos += padded_len
+        value, timestamp = _unpack_two_doubles(data, pos)
+        yield encoded_key.decode('utf-8'), value, timestamp, pos
+        pos += 16
+
+
+class MmapedDict:
+    """A dict of doubles, backed by an mmapped file.
+
+    The file starts with a 4 byte int, indicating how much of it is used.
+    Then 4 bytes of padding.
+    There's then a number of entries, consisting of a 4 byte int which is the
+    size of the next field, a utf-8 encoded string key, padding to a 8 byte
+    alignment, and then a 8 byte float which is the value and a 8 byte float
+    which is a UNIX timestamp in seconds.
+
+    Not thread safe.
+    """
+
+    def __init__(self, filename, read_mode=False):
+        self._f = open(filename, 'rb' if read_mode else 'a+b')
+        self._fname = filename
+        capacity = os.fstat(self._f.fileno()).st_size
+        if capacity == 0:
+            self._f.truncate(_INITIAL_MMAP_SIZE)
+            capacity = _INITIAL_MMAP_SIZE
+        self._capacity = capacity
+        self._m = mmap.mmap(self._f.fileno(), self._capacity,
+                            access=mmap.ACCESS_READ if read_mode else mmap.ACCESS_WRITE)
+
+        self._positions = {}
+        self._used = _unpack_integer(self._m, 0)[0]
+        if self._used == 0:
+            self._used = 8
+            _pack_integer(self._m, 0, self._used)
+        else:
+            if not read_mode:
+                for key, _, _, pos in self._read_all_values():
+                    self._positions[key] = pos
+
+    @staticmethod
+    def read_all_values_from_file(filename):
+        with open(filename, 'rb') as infp:
+            # Read the first block of data, including the first 4 bytes which tell us
+            # how much of the file (which is preallocated to _INITIAL_MMAP_SIZE bytes) is occupied.
+            data = infp.read(mmap.PAGESIZE)
+            used = _unpack_integer(data, 0)[0]
+            if used > len(data):  # Then read in the rest, if needed.
+                data += infp.read(used - len(data))
+        return _read_all_values(data, used)
+
+    def _init_value(self, key):
+        """Initialize a value. Lock must be held by caller."""
+        encoded = key.encode('utf-8')
+        # Pad to be 8-byte aligned.
+        padded = encoded + (b' ' * (8 - (len(encoded) + 4) % 8))
+        value = struct.pack(f'i{len(padded)}sdd'.encode(), len(encoded), padded, 0.0, 0.0)
+        while self._used + len(value) > self._capacity:
+            self._capacity *= 2
+            self._f.truncate(self._capacity)
+            self._m = mmap.mmap(self._f.fileno(), self._capacity)
+        self._m[self._used:self._used + len(value)] = value
+
+        # Update how much space we've used.
+        self._used += len(value)
+        _pack_integer(self._m, 0, self._used)
+        self._positions[key] = self._used - 16
+
+    def _read_all_values(self):
+        """Yield (key, value, pos). No locking is performed."""
+        return _read_all_values(data=self._m, used=self._used)
+
+    def read_all_values(self):
+        """Yield (key, value, timestamp). No locking is performed."""
+        for k, v, ts, _ in self._read_all_values():
+            yield k, v, ts
+
+    def read_value(self, key):
+        if key not in self._positions:
+            self._init_value(key)
+        pos = self._positions[key]
+        return _unpack_two_doubles(self._m, pos)
+
+    def write_value(self, key, value, timestamp):
+        if key not in self._positions:
+            self._init_value(key)
+        pos = self._positions[key]
+        _pack_two_doubles(self._m, pos, value, timestamp)
+
+    def close(self):
+        if self._f:
+            self._m.close()
+            self._m = None
+            self._f.close()
+            self._f = None
+
+
+def mmap_key(metric_name: str, name: str, labelnames: List[str], labelvalues: List[str], help_text: str) -> str:
+    """Format a key for use in the mmap file."""
+    # ensure labels are in consistent order for identity
+    labels = dict(zip(labelnames, labelvalues))
+    return json.dumps([metric_name, name, labels, help_text], sort_keys=True)
diff --git a/zhmc_prometheus_exporter/vendor/prometheus_client/multiprocess.py b/zhmc_prometheus_exporter/vendor/prometheus_client/multiprocess.py
new file mode 100644
index 00000000..7021b49a
--- /dev/null
+++ b/zhmc_prometheus_exporter/vendor/prometheus_client/multiprocess.py
@@ -0,0 +1,170 @@
+from collections import defaultdict
+import glob
+import json
+import os
+import warnings
+
+from .metrics import Gauge
+from .metrics_core import Metric
+from .mmap_dict import MmapedDict
+from .samples import Sample
+from .utils import floatToGoString
+
+try:  # Python3
+    FileNotFoundError
+except NameError:  # Python >= 2.5
+    FileNotFoundError = IOError
+
+
+class MultiProcessCollector:
+    """Collector for files for multi-process mode."""
+
+    def __init__(self, registry, path=None):
+        if path is None:
+            # This deprecation warning can go away in a few releases when removing the compatibility
+            if 'prometheus_multiproc_dir' in os.environ and 'PROMETHEUS_MULTIPROC_DIR' not in os.environ:
+                os.environ['PROMETHEUS_MULTIPROC_DIR'] = os.environ['prometheus_multiproc_dir']
+                warnings.warn("prometheus_multiproc_dir variable has been deprecated in favor of the upper case naming PROMETHEUS_MULTIPROC_DIR", DeprecationWarning)
+            path = os.environ.get('PROMETHEUS_MULTIPROC_DIR')
+        if not path or not os.path.isdir(path):
+            raise ValueError('env PROMETHEUS_MULTIPROC_DIR is not set or not a directory')
+        self._path = path
+        if registry:
+            registry.register(self)
+
+    @staticmethod
+    def merge(files, accumulate=True):
+        """Merge metrics from given mmap files.
+
+        By default, histograms are accumulated, as per prometheus wire format.
+        But if writing the merged data back to mmap files, use
+        accumulate=False to avoid compound accumulation.
+        """
+        metrics = MultiProcessCollector._read_metrics(files)
+        return MultiProcessCollector._accumulate_metrics(metrics, accumulate)
+
+    @staticmethod
+    def _read_metrics(files):
+        metrics = {}
+        key_cache = {}
+
+        def _parse_key(key):
+            val = key_cache.get(key)
+            if not val:
+                metric_name, name, labels, help_text = json.loads(key)
+                labels_key = tuple(sorted(labels.items()))
+                val = key_cache[key] = (metric_name, name, labels, labels_key, help_text)
+            return val
+
+        for f in files:
+            parts = os.path.basename(f).split('_')
+            typ = parts[0]
+            try:
+                file_values = MmapedDict.read_all_values_from_file(f)
+            except FileNotFoundError:
+                if typ == 'gauge' and parts[1].startswith('live'):
+                    # Files for 'live*' gauges can be deleted between the glob of collect
+                    # and now (via a mark_process_dead call) so don't fail if
+                    # the file is missing
+                    continue
+                raise
+            for key, value, timestamp, _ in file_values:
+                metric_name, name, labels, labels_key, help_text = _parse_key(key)
+
+                metric = metrics.get(metric_name)
+                if metric is None:
+                    metric = Metric(metric_name, help_text, typ)
+                    metrics[metric_name] = metric
+
+                if typ == 'gauge':
+                    pid = parts[2][:-3]
+                    metric._multiprocess_mode = parts[1]
+                    metric.add_sample(name, labels_key + (('pid', pid),), value, timestamp)
+                else:
+                    # The duplicates and labels are fixed in the next for.
+                    metric.add_sample(name, labels_key, value)
+        return metrics
+
+    @staticmethod
+    def _accumulate_metrics(metrics, accumulate):
+        for metric in metrics.values():
+            samples = defaultdict(float)
+            sample_timestamps = defaultdict(float)
+            buckets = defaultdict(lambda: defaultdict(float))
+            samples_setdefault = samples.setdefault
+            for s in metric.samples:
+                name, labels, value, timestamp, exemplar = s
+                if metric.type == 'gauge':
+                    without_pid_key = (name, tuple(l for l in labels if l[0] != 'pid'))
+                    if metric._multiprocess_mode in ('min', 'livemin'):
+                        current = samples_setdefault(without_pid_key, value)
+                        if value < current:
+                            samples[without_pid_key] = value
+                    elif metric._multiprocess_mode in ('max', 'livemax'):
+                        current = samples_setdefault(without_pid_key, value)
+                        if value > current:
+                            samples[without_pid_key] = value
+                    elif metric._multiprocess_mode in ('sum', 'livesum'):
+                        samples[without_pid_key] += value
+                    elif metric._multiprocess_mode in ('mostrecent', 'livemostrecent'):
+                        current_timestamp = sample_timestamps[without_pid_key]
+                        timestamp = float(timestamp or 0)
+                        if current_timestamp < timestamp:
+                            samples[without_pid_key] = value
+                            sample_timestamps[without_pid_key] = timestamp
+                    else:  # all/liveall
+                        samples[(name, labels)] = value
+
+                elif metric.type == 'histogram':
+                    # A for loop with early exit is faster than a genexpr
+                    # or a listcomp that ends up building unnecessary things
+                    for l in labels:
+                        if l[0] == 'le':
+                            bucket_value = float(l[1])
+                            # _bucket
+                            without_le = tuple(l for l in labels if l[0] != 'le')
+                            buckets[without_le][bucket_value] += value
+                            break
+                    else:  # did not find the `le` key
+                        # _sum/_count
+                        samples[(name, labels)] += value
+                else:
+                    # Counter and Summary.
+                    samples[(name, labels)] += value
+
+            # Accumulate bucket values.
+            if metric.type == 'histogram':
+                for labels, values in buckets.items():
+                    acc = 0.0
+                    for bucket, value in sorted(values.items()):
+                        sample_key = (
+                            metric.name + '_bucket',
+                            labels + (('le', floatToGoString(bucket)),),
+                        )
+                        if accumulate:
+                            acc += value
+                            samples[sample_key] = acc
+                        else:
+                            samples[sample_key] = value
+                    if accumulate:
+                        samples[(metric.name + '_count', labels)] = acc
+
+            # Convert to correct sample format.
+            metric.samples = [Sample(name_, dict(labels), value) for (name_, labels), value in samples.items()]
+        return metrics.values()
+
+    def collect(self):
+        files = glob.glob(os.path.join(self._path, '*.db'))
+        return self.merge(files, accumulate=True)
+
+
+_LIVE_GAUGE_MULTIPROCESS_MODES = {m for m in Gauge._MULTIPROC_MODES if m.startswith('live')}
+
+
+def mark_process_dead(pid, path=None):
+    """Do bookkeeping for when one process dies in a multi-process setup."""
+    if path is None:
+        path = os.environ.get('PROMETHEUS_MULTIPROC_DIR', os.environ.get('prometheus_multiproc_dir'))
+    for mode in _LIVE_GAUGE_MULTIPROCESS_MODES:
+        for f in glob.glob(os.path.join(path, f'gauge_{mode}_{pid}.db')):
+            os.remove(f)
diff --git a/zhmc_prometheus_exporter/vendor/prometheus_client/openmetrics/__init__.py b/zhmc_prometheus_exporter/vendor/prometheus_client/openmetrics/__init__.py
new file mode 100644
index 00000000..e69de29b
diff --git a/zhmc_prometheus_exporter/vendor/prometheus_client/openmetrics/exposition.py b/zhmc_prometheus_exporter/vendor/prometheus_client/openmetrics/exposition.py
new file mode 100644
index 00000000..26f3109f
--- /dev/null
+++ b/zhmc_prometheus_exporter/vendor/prometheus_client/openmetrics/exposition.py
@@ -0,0 +1,72 @@
+#!/usr/bin/env python
+
+
+from ..utils import floatToGoString
+
+CONTENT_TYPE_LATEST = 'application/openmetrics-text; version=1.0.0; charset=utf-8'
+"""Content type of the latest OpenMetrics text format"""
+
+
+def _is_valid_exemplar_metric(metric, sample):
+    if metric.type == 'counter' and sample.name.endswith('_total'):
+        return True
+    if metric.type in ('histogram', 'gaugehistogram') and sample.name.endswith('_bucket'):
+        return True
+    return False
+
+
+def generate_latest(registry):
+    '''Returns the metrics from the registry in latest text format as a string.'''
+    output = []
+    for metric in registry.collect():
+        try:
+            mname = metric.name
+            output.append('# HELP {} {}\n'.format(
+                mname, metric.documentation.replace('\\', r'\\').replace('\n', r'\n').replace('"', r'\"')))
+            output.append(f'# TYPE {mname} {metric.type}\n')
+            if metric.unit:
+                output.append(f'# UNIT {mname} {metric.unit}\n')
+            for s in metric.samples:
+                if s.labels:
+                    labelstr = '{{{0}}}'.format(','.join(
+                        ['{}="{}"'.format(
+                            k, v.replace('\\', r'\\').replace('\n', r'\n').replace('"', r'\"'))
+                            for k, v in sorted(s.labels.items())]))
+                else:
+                    labelstr = ''
+                if s.exemplar:
+                    if not _is_valid_exemplar_metric(metric, s):
+                        raise ValueError(f"Metric {metric.name} has exemplars, but is not a histogram bucket or counter")
+                    labels = '{{{0}}}'.format(','.join(
+                        ['{}="{}"'.format(
+                            k, v.replace('\\', r'\\').replace('\n', r'\n').replace('"', r'\"'))
+                            for k, v in sorted(s.exemplar.labels.items())]))
+                    if s.exemplar.timestamp is not None:
+                        exemplarstr = ' # {} {} {}'.format(
+                            labels,
+                            floatToGoString(s.exemplar.value),
+                            s.exemplar.timestamp,
+                        )
+                    else:
+                        exemplarstr = ' # {} {}'.format(
+                            labels,
+                            floatToGoString(s.exemplar.value),
+                        )
+                else:
+                    exemplarstr = ''
+                timestamp = ''
+                if s.timestamp is not None:
+                    timestamp = f' {s.timestamp}'
+                output.append('{}{} {}{}{}\n'.format(
+                    s.name,
+                    labelstr,
+                    floatToGoString(s.value),
+                    timestamp,
+                    exemplarstr,
+                ))
+        except Exception as exception:
+            exception.args = (exception.args or ('',)) + (metric,)
+            raise
+
+    output.append('# EOF\n')
+    return ''.join(output).encode('utf-8')
diff --git a/zhmc_prometheus_exporter/vendor/prometheus_client/openmetrics/parser.py b/zhmc_prometheus_exporter/vendor/prometheus_client/openmetrics/parser.py
new file mode 100644
index 00000000..6128a0d3
--- /dev/null
+++ b/zhmc_prometheus_exporter/vendor/prometheus_client/openmetrics/parser.py
@@ -0,0 +1,614 @@
+#!/usr/bin/env python
+
+
+import io as StringIO
+import math
+import re
+
+from ..metrics_core import Metric, METRIC_LABEL_NAME_RE
+from ..samples import Exemplar, Sample, Timestamp
+from ..utils import floatToGoString
+
+
+def text_string_to_metric_families(text):
+    """Parse Openmetrics text format from a unicode string.
+
+    See text_fd_to_metric_families.
+    """
+    yield from text_fd_to_metric_families(StringIO.StringIO(text))
+
+
+_CANONICAL_NUMBERS = {float("inf")}
+
+
+def _isUncanonicalNumber(s):
+    f = float(s)
+    if f not in _CANONICAL_NUMBERS:
+        return False  # Only the canonical numbers are required to be canonical.
+    return s != floatToGoString(f)
+
+
+ESCAPE_SEQUENCES = {
+    '\\\\': '\\',
+    '\\n': '\n',
+    '\\"': '"',
+}
+
+
+def _replace_escape_sequence(match):
+    return ESCAPE_SEQUENCES[match.group(0)]
+
+
+ESCAPING_RE = re.compile(r'\\[\\n"]')
+
+
+def _replace_escaping(s):
+    return ESCAPING_RE.sub(_replace_escape_sequence, s)
+
+
+def _unescape_help(text):
+    result = []
+    slash = False
+
+    for char in text:
+        if slash:
+            if char == '\\':
+                result.append('\\')
+            elif char == '"':
+                result.append('"')
+            elif char == 'n':
+                result.append('\n')
+            else:
+                result.append('\\' + char)
+            slash = False
+        else:
+            if char == '\\':
+                slash = True
+            else:
+                result.append(char)
+
+    if slash:
+        result.append('\\')
+
+    return ''.join(result)
+
+
+def _parse_value(value):
+    value = ''.join(value)
+    if value != value.strip() or '_' in value:
+        raise ValueError(f"Invalid value: {value!r}")
+    try:
+        return int(value)
+    except ValueError:
+        return float(value)
+
+
+def _parse_timestamp(timestamp):
+    timestamp = ''.join(timestamp)
+    if not timestamp:
+        return None
+    if timestamp != timestamp.strip() or '_' in timestamp:
+        raise ValueError(f"Invalid timestamp: {timestamp!r}")
+    try:
+        # Simple int.
+        return Timestamp(int(timestamp), 0)
+    except ValueError:
+        try:
+            # aaaa.bbbb. Nanosecond resolution supported.
+            parts = timestamp.split('.', 1)
+            return Timestamp(int(parts[0]), int(parts[1][:9].ljust(9, "0")))
+        except ValueError:
+            # Float.
+            ts = float(timestamp)
+            if math.isnan(ts) or math.isinf(ts):
+                raise ValueError(f"Invalid timestamp: {timestamp!r}")
+            return ts
+
+
+def _is_character_escaped(s, charpos):
+    num_bslashes = 0
+    while (charpos > num_bslashes
+           and s[charpos - 1 - num_bslashes] == '\\'):
+        num_bslashes += 1
+    return num_bslashes % 2 == 1
+
+
+def _parse_labels_with_state_machine(text):
+    # The { has already been parsed.
+    state = 'startoflabelname'
+    labelname = []
+    labelvalue = []
+    labels = {}
+    labels_len = 0
+
+    for char in text:
+        if state == 'startoflabelname':
+            if char == '}':
+                state = 'endoflabels'
+            else:
+                state = 'labelname'
+                labelname.append(char)
+        elif state == 'labelname':
+            if char == '=':
+                state = 'labelvaluequote'
+            else:
+                labelname.append(char)
+        elif state == 'labelvaluequote':
+            if char == '"':
+                state = 'labelvalue'
+            else:
+                raise ValueError("Invalid line: " + text)
+        elif state == 'labelvalue':
+            if char == '\\':
+                state = 'labelvalueslash'
+            elif char == '"':
+                ln = ''.join(labelname)
+                if not METRIC_LABEL_NAME_RE.match(ln):
+                    raise ValueError("Invalid line, bad label name: " + text)
+                if ln in labels:
+                    raise ValueError("Invalid line, duplicate label name: " + text)
+                labels[ln] = ''.join(labelvalue)
+                labelname = []
+                labelvalue = []
+                state = 'endoflabelvalue'
+            else:
+                labelvalue.append(char)
+        elif state == 'endoflabelvalue':
+            if char == ',':
+                state = 'labelname'
+            elif char == '}':
+                state = 'endoflabels'
+            else:
+                raise ValueError("Invalid line: " + text)
+        elif state == 'labelvalueslash':
+            state = 'labelvalue'
+            if char == '\\':
+                labelvalue.append('\\')
+            elif char == 'n':
+                labelvalue.append('\n')
+            elif char == '"':
+                labelvalue.append('"')
+            else:
+                labelvalue.append('\\' + char)
+        elif state == 'endoflabels':
+            if char == ' ':
+                break
+            else:
+                raise ValueError("Invalid line: " + text)
+        labels_len += 1
+    return labels, labels_len
+
+
+def _parse_labels(text):
+    labels = {}
+
+    # Raise error if we don't have valid labels
+    if text and "=" not in text:
+        raise ValueError
+
+    # Copy original labels
+    sub_labels = text
+    try:
+        # Process one label at a time
+        while sub_labels:
+            # The label name is before the equal
+            value_start = sub_labels.index("=")
+            label_name = sub_labels[:value_start]
+            sub_labels = sub_labels[value_start + 1:]
+
+            # Check for missing quotes 
+            if not sub_labels or sub_labels[0] != '"':
+                raise ValueError
+
+            # The first quote is guaranteed to be after the equal
+            value_substr = sub_labels[1:]
+
+            # Check for extra commas
+            if not label_name or label_name[0] == ',':
+                raise ValueError
+            if not value_substr or value_substr[-1] == ',':
+                raise ValueError
+
+            # Find the last unescaped quote
+            i = 0
+            while i < len(value_substr):
+                i = value_substr.index('"', i)
+                if not _is_character_escaped(value_substr[:i], i):
+                    break
+                i += 1
+
+            # The label value is between the first and last quote
+            quote_end = i + 1
+            label_value = sub_labels[1:quote_end]
+            # Replace escaping if needed
+            if "\\" in label_value:
+                label_value = _replace_escaping(label_value)
+            if not METRIC_LABEL_NAME_RE.match(label_name):
+                raise ValueError("invalid line, bad label name: " + text)
+            if label_name in labels:
+                raise ValueError("invalid line, duplicate label name: " + text)
+            labels[label_name] = label_value
+
+            # Remove the processed label from the sub-slice for next iteration
+            sub_labels = sub_labels[quote_end + 1:]
+            if sub_labels.startswith(","):
+                next_comma = 1
+            else:
+                next_comma = 0
+            sub_labels = sub_labels[next_comma:]
+
+            # Check for missing commas
+            if sub_labels and next_comma == 0:
+                raise ValueError
+            
+        return labels
+
+    except ValueError:
+        raise ValueError("Invalid labels: " + text)
+
+
+def _parse_sample(text):
+    separator = " # "
+    # Detect the labels in the text
+    label_start = text.find("{")
+    if label_start == -1 or separator in text[:label_start]:
+        # We don't have labels, but there could be an exemplar.
+        name_end = text.index(" ")
+        name = text[:name_end]
+        # Parse the remaining text after the name
+        remaining_text = text[name_end + 1:]
+        value, timestamp, exemplar = _parse_remaining_text(remaining_text)
+        return Sample(name, {}, value, timestamp, exemplar)
+    # The name is before the labels
+    name = text[:label_start]
+    if separator not in text:
+        # Line doesn't contain an exemplar
+        # We can use `rindex` to find `label_end`
+        label_end = text.rindex("}")
+        label = text[label_start + 1:label_end]
+        labels = _parse_labels(label)
+    else:
+        # Line potentially contains an exemplar
+        # Fallback to parsing labels with a state machine
+        labels, labels_len = _parse_labels_with_state_machine(text[label_start + 1:])
+        label_end = labels_len + len(name)
+    # Parsing labels succeeded, continue parsing the remaining text
+    remaining_text = text[label_end + 2:]
+    value, timestamp, exemplar = _parse_remaining_text(remaining_text)
+    return Sample(name, labels, value, timestamp, exemplar)
+
+
+def _parse_remaining_text(text):
+    split_text = text.split(" ", 1)
+    val = _parse_value(split_text[0])
+    if len(split_text) == 1:
+        # We don't have timestamp or exemplar
+        return val, None, None  
+
+    timestamp = []
+    exemplar_value = []
+    exemplar_timestamp = []
+    exemplar_labels = None
+
+    state = 'timestamp'
+    text = split_text[1]
+
+    it = iter(text)
+    for char in it:
+        if state == 'timestamp':
+            if char == '#' and not timestamp:
+                state = 'exemplarspace'
+            elif char == ' ':
+                state = 'exemplarhash'
+            else:
+                timestamp.append(char)
+        elif state == 'exemplarhash':
+            if char == '#':
+                state = 'exemplarspace'
+            else:
+                raise ValueError("Invalid line: " + text)
+        elif state == 'exemplarspace':
+            if char == ' ':
+                state = 'exemplarstartoflabels'
+            else:
+                raise ValueError("Invalid line: " + text)
+        elif state == 'exemplarstartoflabels':
+            if char == '{':
+                label_start, label_end = text.index("{"), text.rindex("}")
+                exemplar_labels = _parse_labels(text[label_start + 1:label_end])
+                state = 'exemplarparsedlabels'
+            else:
+                raise ValueError("Invalid line: " + text)
+        elif state == 'exemplarparsedlabels':
+            if char == '}':
+                state = 'exemplarvaluespace'
+        elif state == 'exemplarvaluespace':
+            if char == ' ':
+                state = 'exemplarvalue'
+            else:
+                raise ValueError("Invalid line: " + text)
+        elif state == 'exemplarvalue':
+            if char == ' ' and not exemplar_value:
+                raise ValueError("Invalid line: " + text)
+            elif char == ' ':
+                state = 'exemplartimestamp'
+            else:
+                exemplar_value.append(char)
+        elif state == 'exemplartimestamp':
+            exemplar_timestamp.append(char)
+
+    # Trailing space after value.
+    if state == 'timestamp' and not timestamp:
+        raise ValueError("Invalid line: " + text)
+
+    # Trailing space after value.
+    if state == 'exemplartimestamp' and not exemplar_timestamp:
+        raise ValueError("Invalid line: " + text)
+
+    # Incomplete exemplar.
+    if state in ['exemplarhash', 'exemplarspace', 'exemplarstartoflabels', 'exemplarparsedlabels']:
+        raise ValueError("Invalid line: " + text)
+
+    ts = _parse_timestamp(timestamp)
+    exemplar = None
+    if exemplar_labels is not None:
+        exemplar_length = sum(len(k) + len(v) for k, v in exemplar_labels.items())
+        if exemplar_length > 128:
+            raise ValueError("Exemplar labels are too long: " + text)
+        exemplar = Exemplar(
+            exemplar_labels,
+            _parse_value(exemplar_value),
+            _parse_timestamp(exemplar_timestamp),
+        )
+
+    return val, ts, exemplar
+
+
+def _group_for_sample(sample, name, typ):
+    if typ == 'info':
+        # We can't distinguish between groups for info metrics.
+        return {}
+    if typ == 'summary' and sample.name == name:
+        d = sample.labels.copy()
+        del d['quantile']
+        return d
+    if typ == 'stateset':
+        d = sample.labels.copy()
+        del d[name]
+        return d
+    if typ in ['histogram', 'gaugehistogram'] and sample.name == name + '_bucket':
+        d = sample.labels.copy()
+        del d['le']
+        return d
+    return sample.labels
+
+
+def _check_histogram(samples, name):
+    group = None
+    timestamp = None
+
+    def do_checks():
+        if bucket != float('+Inf'):
+            raise ValueError("+Inf bucket missing: " + name)
+        if count is not None and value != count:
+            raise ValueError("Count does not match +Inf value: " + name)
+        if has_sum and count is None:
+            raise ValueError("_count must be present if _sum is present: " + name)
+        if has_gsum and count is None:
+            raise ValueError("_gcount must be present if _gsum is present: " + name)
+        if not (has_sum or has_gsum) and count is not None:
+            raise ValueError("_sum/_gsum must be present if _count is present: " + name)
+        if has_negative_buckets and has_sum:
+            raise ValueError("Cannot have _sum with negative buckets: " + name)
+        if not has_negative_buckets and has_negative_gsum:
+            raise ValueError("Cannot have negative _gsum with non-negative buckets: " + name)
+
+    for s in samples:
+        suffix = s.name[len(name):]
+        g = _group_for_sample(s, name, 'histogram')
+        if g != group or s.timestamp != timestamp:
+            if group is not None:
+                do_checks()
+            count = None
+            bucket = None
+            has_negative_buckets = False
+            has_sum = False
+            has_gsum = False
+            has_negative_gsum = False
+            value = 0
+        group = g
+        timestamp = s.timestamp
+
+        if suffix == '_bucket':
+            b = float(s.labels['le'])
+            if b < 0:
+                has_negative_buckets = True
+            if bucket is not None and b <= bucket:
+                raise ValueError("Buckets out of order: " + name)
+            if s.value < value:
+                raise ValueError("Bucket values out of order: " + name)
+            bucket = b
+            value = s.value
+        elif suffix in ['_count', '_gcount']:
+            count = s.value
+        elif suffix in ['_sum']:
+            has_sum = True
+        elif suffix in ['_gsum']:
+            has_gsum = True
+            if s.value < 0:
+                has_negative_gsum = True
+
+    if group is not None:
+        do_checks()
+
+
+def text_fd_to_metric_families(fd):
+    """Parse Prometheus text format from a file descriptor.
+
+    This is a laxer parser than the main Go parser,
+    so successful parsing does not imply that the parsed
+    text meets the specification.
+
+    Yields Metric's.
+    """
+    name = None
+    allowed_names = []
+    eof = False
+
+    seen_names = set()
+    type_suffixes = {
+        'counter': ['_total', '_created'],
+        'summary': ['', '_count', '_sum', '_created'],
+        'histogram': ['_count', '_sum', '_bucket', '_created'],
+        'gaugehistogram': ['_gcount', '_gsum', '_bucket'],
+        'info': ['_info'],
+    }
+
+    def build_metric(name, documentation, typ, unit, samples):
+        if typ is None:
+            typ = 'unknown'
+        for suffix in set(type_suffixes.get(typ, []) + [""]):
+            if name + suffix in seen_names:
+                raise ValueError("Clashing name: " + name + suffix)
+            seen_names.add(name + suffix)
+        if documentation is None:
+            documentation = ''
+        if unit is None:
+            unit = ''
+        if unit and not name.endswith("_" + unit):
+            raise ValueError("Unit does not match metric name: " + name)
+        if unit and typ in ['info', 'stateset']:
+            raise ValueError("Units not allowed for this metric type: " + name)
+        if typ in ['histogram', 'gaugehistogram']:
+            _check_histogram(samples, name)
+        metric = Metric(name, documentation, typ, unit)
+        # TODO: check labelvalues are valid utf8
+        metric.samples = samples
+        return metric
+
+    for line in fd:
+        if line[-1] == '\n':
+            line = line[:-1]
+
+        if eof:
+            raise ValueError("Received line after # EOF: " + line)
+
+        if not line:
+            raise ValueError("Received blank line")
+
+        if line == '# EOF':
+            eof = True
+        elif line.startswith('#'):
+            parts = line.split(' ', 3)
+            if len(parts) < 4:
+                raise ValueError("Invalid line: " + line)
+            if parts[2] == name and samples:
+                raise ValueError("Received metadata after samples: " + line)
+            if parts[2] != name:
+                if name is not None:
+                    yield build_metric(name, documentation, typ, unit, samples)
+                # New metric
+                name = parts[2]
+                unit = None
+                typ = None
+                documentation = None
+                group = None
+                seen_groups = set()
+                group_timestamp = None
+                group_timestamp_samples = set()
+                samples = []
+                allowed_names = [parts[2]]
+
+            if parts[1] == 'HELP':
+                if documentation is not None:
+                    raise ValueError("More than one HELP for metric: " + line)
+                documentation = _unescape_help(parts[3])
+            elif parts[1] == 'TYPE':
+                if typ is not None:
+                    raise ValueError("More than one TYPE for metric: " + line)
+                typ = parts[3]
+                if typ == 'untyped':
+                    raise ValueError("Invalid TYPE for metric: " + line)
+                allowed_names = [name + n for n in type_suffixes.get(typ, [''])]
+            elif parts[1] == 'UNIT':
+                if unit is not None:
+                    raise ValueError("More than one UNIT for metric: " + line)
+                unit = parts[3]
+            else:
+                raise ValueError("Invalid line: " + line)
+        else:
+            sample = _parse_sample(line)
+            if sample.name not in allowed_names:
+                if name is not None:
+                    yield build_metric(name, documentation, typ, unit, samples)
+                # Start an unknown metric.
+                name = sample.name
+                documentation = None
+                unit = None
+                typ = 'unknown'
+                samples = []
+                group = None
+                group_timestamp = None
+                group_timestamp_samples = set()
+                seen_groups = set()
+                allowed_names = [sample.name]
+
+            if typ == 'stateset' and name not in sample.labels:
+                raise ValueError("Stateset missing label: " + line)
+            if (name + '_bucket' == sample.name
+                    and (sample.labels.get('le', "NaN") == "NaN"
+                         or _isUncanonicalNumber(sample.labels['le']))):
+                raise ValueError("Invalid le label: " + line)
+            if (name + '_bucket' == sample.name
+                    and (not isinstance(sample.value, int) and not sample.value.is_integer())):
+                raise ValueError("Bucket value must be an integer: " + line)
+            if ((name + '_count' == sample.name or name + '_gcount' == sample.name)
+                    and (not isinstance(sample.value, int) and not sample.value.is_integer())):
+                raise ValueError("Count value must be an integer: " + line)
+            if (typ == 'summary' and name == sample.name
+                    and (not (0 <= float(sample.labels.get('quantile', -1)) <= 1)
+                         or _isUncanonicalNumber(sample.labels['quantile']))):
+                raise ValueError("Invalid quantile label: " + line)
+
+            g = tuple(sorted(_group_for_sample(sample, name, typ).items()))
+            if group is not None and g != group and g in seen_groups:
+                raise ValueError("Invalid metric grouping: " + line)
+            if group is not None and g == group:
+                if (sample.timestamp is None) != (group_timestamp is None):
+                    raise ValueError("Mix of timestamp presence within a group: " + line)
+                if group_timestamp is not None and group_timestamp > sample.timestamp and typ != 'info':
+                    raise ValueError("Timestamps went backwards within a group: " + line)
+            else:
+                group_timestamp_samples = set()
+
+            series_id = (sample.name, tuple(sorted(sample.labels.items())))
+            if sample.timestamp != group_timestamp or series_id not in group_timestamp_samples:
+                # Not a duplicate due to timestamp truncation.
+                samples.append(sample)
+            group_timestamp_samples.add(series_id)
+
+            group = g
+            group_timestamp = sample.timestamp
+            seen_groups.add(g)
+
+            if typ == 'stateset' and sample.value not in [0, 1]:
+                raise ValueError("Stateset samples can only have values zero and one: " + line)
+            if typ == 'info' and sample.value != 1:
+                raise ValueError("Info samples can only have value one: " + line)
+            if typ == 'summary' and name == sample.name and sample.value < 0:
+                raise ValueError("Quantile values cannot be negative: " + line)
+            if sample.name[len(name):] in ['_total', '_sum', '_count', '_bucket', '_gcount', '_gsum'] and math.isnan(
+                    sample.value):
+                raise ValueError("Counter-like samples cannot be NaN: " + line)
+            if sample.name[len(name):] in ['_total', '_sum', '_count', '_bucket', '_gcount'] and sample.value < 0:
+                raise ValueError("Counter-like samples cannot be negative: " + line)
+            if sample.exemplar and not (
+                    (typ in ['histogram', 'gaugehistogram'] and sample.name.endswith('_bucket'))
+                    or (typ in ['counter'] and sample.name.endswith('_total'))):
+                raise ValueError("Invalid line only histogram/gaugehistogram buckets and counters can have exemplars: " + line)
+
+    if name is not None:
+        yield build_metric(name, documentation, typ, unit, samples)
+
+    if not eof:
+        raise ValueError("Missing # EOF at end")
diff --git a/zhmc_prometheus_exporter/vendor/prometheus_client/parser.py b/zhmc_prometheus_exporter/vendor/prometheus_client/parser.py
new file mode 100644
index 00000000..dc8e30df
--- /dev/null
+++ b/zhmc_prometheus_exporter/vendor/prometheus_client/parser.py
@@ -0,0 +1,225 @@
+import io as StringIO
+import re
+from typing import Dict, Iterable, List, Match, Optional, TextIO, Tuple
+
+from .metrics_core import Metric
+from .samples import Sample
+
+
+def text_string_to_metric_families(text: str) -> Iterable[Metric]:
+    """Parse Prometheus text format from a unicode string.
+
+    See text_fd_to_metric_families.
+    """
+    yield from text_fd_to_metric_families(StringIO.StringIO(text))
+
+
+ESCAPE_SEQUENCES = {
+    '\\\\': '\\',
+    '\\n': '\n',
+    '\\"': '"',
+}
+
+
+def replace_escape_sequence(match: Match[str]) -> str:
+    return ESCAPE_SEQUENCES[match.group(0)]
+
+
+HELP_ESCAPING_RE = re.compile(r'\\[\\n]')
+ESCAPING_RE = re.compile(r'\\[\\n"]')
+
+
+def _replace_help_escaping(s: str) -> str:
+    return HELP_ESCAPING_RE.sub(replace_escape_sequence, s)
+
+
+def _replace_escaping(s: str) -> str:
+    return ESCAPING_RE.sub(replace_escape_sequence, s)
+
+
+def _is_character_escaped(s: str, charpos: int) -> bool:
+    num_bslashes = 0
+    while (charpos > num_bslashes
+           and s[charpos - 1 - num_bslashes] == '\\'):
+        num_bslashes += 1
+    return num_bslashes % 2 == 1
+
+
+def _parse_labels(labels_string: str) -> Dict[str, str]:
+    labels: Dict[str, str] = {}
+    # Return if we don't have valid labels
+    if "=" not in labels_string:
+        return labels
+
+    escaping = False
+    if "\\" in labels_string:
+        escaping = True
+
+    # Copy original labels
+    sub_labels = labels_string
+    try:
+        # Process one label at a time
+        while sub_labels:
+            # The label name is before the equal
+            value_start = sub_labels.index("=")
+            label_name = sub_labels[:value_start]
+            sub_labels = sub_labels[value_start + 1:].lstrip()
+            # Find the first quote after the equal
+            quote_start = sub_labels.index('"') + 1
+            value_substr = sub_labels[quote_start:]
+
+            # Find the last unescaped quote
+            i = 0
+            while i < len(value_substr):
+                i = value_substr.index('"', i)
+                if not _is_character_escaped(value_substr, i):
+                    break
+                i += 1
+
+            # The label value is between the first and last quote
+            quote_end = i + 1
+            label_value = sub_labels[quote_start:quote_end]
+            # Replace escaping if needed
+            if escaping:
+                label_value = _replace_escaping(label_value)
+            labels[label_name.strip()] = label_value
+
+            # Remove the processed label from the sub-slice for next iteration
+            sub_labels = sub_labels[quote_end + 1:]
+            next_comma = sub_labels.find(",") + 1
+            sub_labels = sub_labels[next_comma:].lstrip()
+
+        return labels
+
+    except ValueError:
+        raise ValueError("Invalid labels: %s" % labels_string)
+
+
+# If we have multiple values only consider the first
+def _parse_value_and_timestamp(s: str) -> Tuple[float, Optional[float]]:
+    s = s.lstrip()
+    separator = " "
+    if separator not in s:
+        separator = "\t"
+    values = [value.strip() for value in s.split(separator) if value.strip()]
+    if not values:
+        return float(s), None
+    value = float(values[0])
+    timestamp = (float(values[-1]) / 1000) if len(values) > 1 else None
+    return value, timestamp
+
+
+def _parse_sample(text: str) -> Sample:
+    # Detect the labels in the text
+    try:
+        label_start, label_end = text.index("{"), text.rindex("}")
+        # The name is before the labels
+        name = text[:label_start].strip()
+        # We ignore the starting curly brace
+        label = text[label_start + 1:label_end]
+        # The value is after the label end (ignoring curly brace)
+        value, timestamp = _parse_value_and_timestamp(text[label_end + 1:])
+        return Sample(name, _parse_labels(label), value, timestamp)
+
+    # We don't have labels
+    except ValueError:
+        # Detect what separator is used
+        separator = " "
+        if separator not in text:
+            separator = "\t"
+        name_end = text.index(separator)
+        name = text[:name_end]
+        # The value is after the name
+        value, timestamp = _parse_value_and_timestamp(text[name_end:])
+        return Sample(name, {}, value, timestamp)
+
+
+def text_fd_to_metric_families(fd: TextIO) -> Iterable[Metric]:
+    """Parse Prometheus text format from a file descriptor.
+
+    This is a laxer parser than the main Go parser,
+    so successful parsing does not imply that the parsed
+    text meets the specification.
+
+    Yields Metric's.
+    """
+    name = ''
+    documentation = ''
+    typ = 'untyped'
+    samples: List[Sample] = []
+    allowed_names = []
+
+    def build_metric(name: str, documentation: str, typ: str, samples: List[Sample]) -> Metric:
+        # Munge counters into OpenMetrics representation
+        # used internally.
+        if typ == 'counter':
+            if name.endswith('_total'):
+                name = name[:-6]
+            else:
+                new_samples = []
+                for s in samples:
+                    new_samples.append(Sample(s[0] + '_total', *s[1:]))
+                    samples = new_samples
+        metric = Metric(name, documentation, typ)
+        metric.samples = samples
+        return metric
+
+    for line in fd:
+        line = line.strip()
+
+        if line.startswith('#'):
+            parts = line.split(None, 3)
+            if len(parts) < 2:
+                continue
+            if parts[1] == 'HELP':
+                if parts[2] != name:
+                    if name != '':
+                        yield build_metric(name, documentation, typ, samples)
+                    # New metric
+                    name = parts[2]
+                    typ = 'untyped'
+                    samples = []
+                    allowed_names = [parts[2]]
+                if len(parts) == 4:
+                    documentation = _replace_help_escaping(parts[3])
+                else:
+                    documentation = ''
+            elif parts[1] == 'TYPE':
+                if parts[2] != name:
+                    if name != '':
+                        yield build_metric(name, documentation, typ, samples)
+                    # New metric
+                    name = parts[2]
+                    documentation = ''
+                    samples = []
+                typ = parts[3]
+                allowed_names = {
+                    'counter': [''],
+                    'gauge': [''],
+                    'summary': ['_count', '_sum', ''],
+                    'histogram': ['_count', '_sum', '_bucket'],
+                }.get(typ, [''])
+                allowed_names = [name + n for n in allowed_names]
+            else:
+                # Ignore other comment tokens
+                pass
+        elif line == '':
+            # Ignore blank lines
+            pass
+        else:
+            sample = _parse_sample(line)
+            if sample.name not in allowed_names:
+                if name != '':
+                    yield build_metric(name, documentation, typ, samples)
+                # New metric, yield immediately as untyped singleton
+                name = ''
+                documentation = ''
+                typ = 'untyped'
+                samples = []
+                allowed_names = []
+                yield build_metric(sample[0], documentation, typ, [sample])
+            else:
+                samples.append(sample)
+
+    if name != '':
+        yield build_metric(name, documentation, typ, samples)
diff --git a/zhmc_prometheus_exporter/vendor/prometheus_client/platform_collector.py b/zhmc_prometheus_exporter/vendor/prometheus_client/platform_collector.py
new file mode 100644
index 00000000..6040fcce
--- /dev/null
+++ b/zhmc_prometheus_exporter/vendor/prometheus_client/platform_collector.py
@@ -0,0 +1,59 @@
+import platform as pf
+from typing import Any, Iterable, Optional
+
+from .metrics_core import GaugeMetricFamily, Metric
+from .registry import Collector, CollectorRegistry, REGISTRY
+
+
+class PlatformCollector(Collector):
+    """Collector for python platform information"""
+
+    def __init__(self,
+                 registry: Optional[CollectorRegistry] = REGISTRY,
+                 platform: Optional[Any] = None,
+                 ):
+        self._platform = pf if platform is None else platform
+        info = self._info()
+        system = self._platform.system()
+        if system == "Java":
+            info.update(self._java())
+        self._metrics = [
+            self._add_metric("python_info", "Python platform information", info)
+        ]
+        if registry:
+            registry.register(self)
+
+    def collect(self) -> Iterable[Metric]:
+        return self._metrics
+
+    @staticmethod
+    def _add_metric(name, documentation, data):
+        labels = data.keys()
+        values = [data[k] for k in labels]
+        g = GaugeMetricFamily(name, documentation, labels=labels)
+        g.add_metric(values, 1)
+        return g
+
+    def _info(self):
+        major, minor, patchlevel = self._platform.python_version_tuple()
+        return {
+            "version": self._platform.python_version(),
+            "implementation": self._platform.python_implementation(),
+            "major": major,
+            "minor": minor,
+            "patchlevel": patchlevel
+        }
+
+    def _java(self):
+        java_version, _, vminfo, osinfo = self._platform.java_ver()
+        vm_name, vm_release, vm_vendor = vminfo
+        return {
+            "jvm_version": java_version,
+            "jvm_release": vm_release,
+            "jvm_vendor": vm_vendor,
+            "jvm_name": vm_name
+        }
+
+
+PLATFORM_COLLECTOR = PlatformCollector()
+"""PlatformCollector in default Registry REGISTRY"""
diff --git a/zhmc_prometheus_exporter/vendor/prometheus_client/process_collector.py b/zhmc_prometheus_exporter/vendor/prometheus_client/process_collector.py
new file mode 100644
index 00000000..2894e874
--- /dev/null
+++ b/zhmc_prometheus_exporter/vendor/prometheus_client/process_collector.py
@@ -0,0 +1,101 @@
+import os
+from typing import Callable, Iterable, Optional, Union
+
+from .metrics_core import CounterMetricFamily, GaugeMetricFamily, Metric
+from .registry import Collector, CollectorRegistry, REGISTRY
+
+try:
+    import resource
+
+    _PAGESIZE = resource.getpagesize()
+except ImportError:
+    # Not Unix
+    _PAGESIZE = 4096
+
+
+class ProcessCollector(Collector):
+    """Collector for Standard Exports such as cpu and memory."""
+
+    def __init__(self,
+                 namespace: str = '',
+                 pid: Callable[[], Union[int, str]] = lambda: 'self',
+                 proc: str = '/proc',
+                 registry: Optional[CollectorRegistry] = REGISTRY):
+        self._namespace = namespace
+        self._pid = pid
+        self._proc = proc
+        if namespace:
+            self._prefix = namespace + '_process_'
+        else:
+            self._prefix = 'process_'
+        self._ticks = 100.0
+        try:
+            self._ticks = os.sysconf('SC_CLK_TCK')
+        except (ValueError, TypeError, AttributeError, OSError):
+            pass
+
+        self._pagesize = _PAGESIZE
+
+        # This is used to test if we can access /proc.
+        self._btime = 0
+        try:
+            self._btime = self._boot_time()
+        except OSError:
+            pass
+        if registry:
+            registry.register(self)
+
+    def _boot_time(self):
+        with open(os.path.join(self._proc, 'stat'), 'rb') as stat:
+            for line in stat:
+                if line.startswith(b'btime '):
+                    return float(line.split()[1])
+
+    def collect(self) -> Iterable[Metric]:
+        if not self._btime:
+            return []
+
+        pid = os.path.join(self._proc, str(self._pid()).strip())
+
+        result = []
+        try:
+            with open(os.path.join(pid, 'stat'), 'rb') as stat:
+                parts = (stat.read().split(b')')[-1].split())
+
+            vmem = GaugeMetricFamily(self._prefix + 'virtual_memory_bytes',
+                                     'Virtual memory size in bytes.', value=float(parts[20]))
+            rss = GaugeMetricFamily(self._prefix + 'resident_memory_bytes', 'Resident memory size in bytes.',
+                                    value=float(parts[21]) * self._pagesize)
+            start_time_secs = float(parts[19]) / self._ticks
+            start_time = GaugeMetricFamily(self._prefix + 'start_time_seconds',
+                                           'Start time of the process since unix epoch in seconds.',
+                                           value=start_time_secs + self._btime)
+            utime = float(parts[11]) / self._ticks
+            stime = float(parts[12]) / self._ticks
+            cpu = CounterMetricFamily(self._prefix + 'cpu_seconds_total',
+                                      'Total user and system CPU time spent in seconds.',
+                                      value=utime + stime)
+            result.extend([vmem, rss, start_time, cpu])
+        except OSError:
+            pass
+
+        try:
+            with open(os.path.join(pid, 'limits'), 'rb') as limits:
+                for line in limits:
+                    if line.startswith(b'Max open file'):
+                        max_fds = GaugeMetricFamily(self._prefix + 'max_fds',
+                                                    'Maximum number of open file descriptors.',
+                                                    value=float(line.split()[3]))
+                        break
+            open_fds = GaugeMetricFamily(self._prefix + 'open_fds',
+                                         'Number of open file descriptors.',
+                                         len(os.listdir(os.path.join(pid, 'fd'))))
+            result.extend([open_fds, max_fds])
+        except OSError:
+            pass
+
+        return result
+
+
+PROCESS_COLLECTOR = ProcessCollector()
+"""Default ProcessCollector in default Registry REGISTRY."""
diff --git a/zhmc_prometheus_exporter/vendor/prometheus_client/py.typed b/zhmc_prometheus_exporter/vendor/prometheus_client/py.typed
new file mode 100644
index 00000000..e69de29b
diff --git a/zhmc_prometheus_exporter/vendor/prometheus_client/registry.py b/zhmc_prometheus_exporter/vendor/prometheus_client/registry.py
new file mode 100644
index 00000000..694e4bd8
--- /dev/null
+++ b/zhmc_prometheus_exporter/vendor/prometheus_client/registry.py
@@ -0,0 +1,168 @@
+from abc import ABC, abstractmethod
+import copy
+from threading import Lock
+from typing import Dict, Iterable, List, Optional
+
+from .metrics_core import Metric
+
+
+# Ideally this would be a Protocol, but Protocols are only available in Python >= 3.8.
+class Collector(ABC):
+    @abstractmethod
+    def collect(self) -> Iterable[Metric]:
+        pass
+
+
+class _EmptyCollector(Collector):
+    def collect(self) -> Iterable[Metric]:
+        return []
+
+
+class CollectorRegistry(Collector):
+    """Metric collector registry.
+
+    Collectors must have a no-argument method 'collect' that returns a list of
+    Metric objects. The returned metrics should be consistent with the Prometheus
+    exposition formats.
+    """
+
+    def __init__(self, auto_describe: bool = False, target_info: Optional[Dict[str, str]] = None):
+        self._collector_to_names: Dict[Collector, List[str]] = {}
+        self._names_to_collectors: Dict[str, Collector] = {}
+        self._auto_describe = auto_describe
+        self._lock = Lock()
+        self._target_info: Optional[Dict[str, str]] = {}
+        self.set_target_info(target_info)
+
+    def register(self, collector: Collector) -> None:
+        """Add a collector to the registry."""
+        with self._lock:
+            names = self._get_names(collector)
+            duplicates = set(self._names_to_collectors).intersection(names)
+            if duplicates:
+                raise ValueError(
+                    'Duplicated timeseries in CollectorRegistry: {}'.format(
+                        duplicates))
+            for name in names:
+                self._names_to_collectors[name] = collector
+            self._collector_to_names[collector] = names
+
+    def unregister(self, collector: Collector) -> None:
+        """Remove a collector from the registry."""
+        with self._lock:
+            for name in self._collector_to_names[collector]:
+                del self._names_to_collectors[name]
+            del self._collector_to_names[collector]
+
+    def _get_names(self, collector):
+        """Get names of timeseries the collector produces and clashes with."""
+        desc_func = None
+        # If there's a describe function, use it.
+        try:
+            desc_func = collector.describe
+        except AttributeError:
+            pass
+        # Otherwise, if auto describe is enabled use the collect function.
+        if not desc_func and self._auto_describe:
+            desc_func = collector.collect
+
+        if not desc_func:
+            return []
+
+        result = []
+        type_suffixes = {
+            'counter': ['_total', '_created'],
+            'summary': ['_sum', '_count', '_created'],
+            'histogram': ['_bucket', '_sum', '_count', '_created'],
+            'gaugehistogram': ['_bucket', '_gsum', '_gcount'],
+            'info': ['_info'],
+        }
+        for metric in desc_func():
+            result.append(metric.name)
+            for suffix in type_suffixes.get(metric.type, []):
+                result.append(metric.name + suffix)
+        return result
+
+    def collect(self) -> Iterable[Metric]:
+        """Yields metrics from the collectors in the registry."""
+        collectors = None
+        ti = None
+        with self._lock:
+            collectors = copy.copy(self._collector_to_names)
+            if self._target_info:
+                ti = self._target_info_metric()
+        if ti:
+            yield ti
+        for collector in collectors:
+            yield from collector.collect()
+
+    def restricted_registry(self, names: Iterable[str]) -> "RestrictedRegistry":
+        """Returns object that only collects some metrics.
+
+        Returns an object which upon collect() will return
+        only samples with the given names.
+
+        Intended usage is:
+            generate_latest(REGISTRY.restricted_registry(['a_timeseries']))
+
+        Experimental."""
+        names = set(names)
+        return RestrictedRegistry(names, self)
+
+    def set_target_info(self, labels: Optional[Dict[str, str]]) -> None:
+        with self._lock:
+            if labels:
+                if not self._target_info and 'target_info' in self._names_to_collectors:
+                    raise ValueError('CollectorRegistry already contains a target_info metric')
+                self._names_to_collectors['target_info'] = _EmptyCollector()
+            elif self._target_info:
+                self._names_to_collectors.pop('target_info', None)
+            self._target_info = labels
+
+    def get_target_info(self) -> Optional[Dict[str, str]]:
+        with self._lock:
+            return self._target_info
+
+    def _target_info_metric(self):
+        m = Metric('target', 'Target metadata', 'info')
+        m.add_sample('target_info', self._target_info, 1)
+        return m
+
+    def get_sample_value(self, name: str, labels: Optional[Dict[str, str]] = None) -> Optional[float]:
+        """Returns the sample value, or None if not found.
+
+        This is inefficient, and intended only for use in unittests.
+        """
+        if labels is None:
+            labels = {}
+        for metric in self.collect():
+            for s in metric.samples:
+                if s.name == name and s.labels == labels:
+                    return s.value
+        return None
+
+
+class RestrictedRegistry:
+    def __init__(self, names: Iterable[str], registry: CollectorRegistry):
+        self._name_set = set(names)
+        self._registry = registry
+
+    def collect(self) -> Iterable[Metric]:
+        collectors = set()
+        target_info_metric = None
+        with self._registry._lock:
+            if 'target_info' in self._name_set and self._registry._target_info:
+                target_info_metric = self._registry._target_info_metric()
+            for name in self._name_set:
+                if name != 'target_info' and name in self._registry._names_to_collectors:
+                    collectors.add(self._registry._names_to_collectors[name])
+        if target_info_metric:
+            yield target_info_metric
+        for collector in collectors:
+            for metric in collector.collect():
+                m = metric._restricted_metric(self._name_set)
+                if m:
+                    yield m
+
+
+REGISTRY = CollectorRegistry(auto_describe=True)
diff --git a/zhmc_prometheus_exporter/vendor/prometheus_client/samples.py b/zhmc_prometheus_exporter/vendor/prometheus_client/samples.py
new file mode 100644
index 00000000..53c47264
--- /dev/null
+++ b/zhmc_prometheus_exporter/vendor/prometheus_client/samples.py
@@ -0,0 +1,53 @@
+from typing import Dict, NamedTuple, Optional, Union
+
+
+class Timestamp:
+    """A nanosecond-resolution timestamp."""
+
+    def __init__(self, sec: float, nsec: float) -> None:
+        if nsec < 0 or nsec >= 1e9:
+            raise ValueError(f"Invalid value for nanoseconds in Timestamp: {nsec}")
+        if sec < 0:
+            nsec = -nsec
+        self.sec: int = int(sec)
+        self.nsec: int = int(nsec)
+
+    def __str__(self) -> str:
+        return f"{self.sec}.{self.nsec:09d}"
+
+    def __repr__(self) -> str:
+        return f"Timestamp({self.sec}, {self.nsec})"
+
+    def __float__(self) -> float:
+        return float(self.sec) + float(self.nsec) / 1e9
+
+    def __eq__(self, other: object) -> bool:
+        return isinstance(other, Timestamp) and self.sec == other.sec and self.nsec == other.nsec
+
+    def __ne__(self, other: object) -> bool:
+        return not self == other
+
+    def __gt__(self, other: "Timestamp") -> bool:
+        return self.nsec > other.nsec if self.sec == other.sec else self.sec > other.sec
+
+    def __lt__(self, other: "Timestamp") -> bool:
+        return self.nsec < other.nsec if self.sec == other.sec else self.sec < other.sec
+
+
+# Timestamp and exemplar are optional.
+# Value can be an int or a float.
+# Timestamp can be a float containing a unixtime in seconds,
+# a Timestamp object, or None.
+# Exemplar can be an Exemplar object, or None.
+class Exemplar(NamedTuple):
+    labels: Dict[str, str]
+    value: float
+    timestamp: Optional[Union[float, Timestamp]] = None
+
+
+class Sample(NamedTuple):
+    name: str
+    labels: Dict[str, str]
+    value: float
+    timestamp: Optional[Union[float, Timestamp]] = None
+    exemplar: Optional[Exemplar] = None
diff --git a/zhmc_prometheus_exporter/vendor/prometheus_client/twisted/__init__.py b/zhmc_prometheus_exporter/vendor/prometheus_client/twisted/__init__.py
new file mode 100644
index 00000000..87e0b8a6
--- /dev/null
+++ b/zhmc_prometheus_exporter/vendor/prometheus_client/twisted/__init__.py
@@ -0,0 +1,3 @@
+from ._exposition import MetricsResource
+
+__all__ = ['MetricsResource']
diff --git a/zhmc_prometheus_exporter/vendor/prometheus_client/twisted/_exposition.py b/zhmc_prometheus_exporter/vendor/prometheus_client/twisted/_exposition.py
new file mode 100644
index 00000000..202a7d3b
--- /dev/null
+++ b/zhmc_prometheus_exporter/vendor/prometheus_client/twisted/_exposition.py
@@ -0,0 +1,8 @@
+from twisted.internet import reactor
+from twisted.web.wsgi import WSGIResource
+
+from .. import exposition, REGISTRY
+
+MetricsResource = lambda registry=REGISTRY: WSGIResource(
+    reactor, reactor.getThreadPool(), exposition.make_wsgi_app(registry)
+)
diff --git a/zhmc_prometheus_exporter/vendor/prometheus_client/utils.py b/zhmc_prometheus_exporter/vendor/prometheus_client/utils.py
new file mode 100644
index 00000000..0d2b0948
--- /dev/null
+++ b/zhmc_prometheus_exporter/vendor/prometheus_client/utils.py
@@ -0,0 +1,24 @@
+import math
+
+INF = float("inf")
+MINUS_INF = float("-inf")
+NaN = float("NaN")
+
+
+def floatToGoString(d):
+    d = float(d)
+    if d == INF:
+        return '+Inf'
+    elif d == MINUS_INF:
+        return '-Inf'
+    elif math.isnan(d):
+        return 'NaN'
+    else:
+        s = repr(d)
+        dot = s.find('.')
+        # Go switches to exponents sooner than Python.
+        # We only need to care about positive values for le/quantile.
+        if d > 0 and dot > 6:
+            mantissa = f'{s[0]}.{s[1:dot]}{s[dot + 1:]}'.rstrip('0.')
+            return f'{mantissa}e+0{dot - 1}'
+        return s
diff --git a/zhmc_prometheus_exporter/vendor/prometheus_client/values.py b/zhmc_prometheus_exporter/vendor/prometheus_client/values.py
new file mode 100644
index 00000000..6ff85e3b
--- /dev/null
+++ b/zhmc_prometheus_exporter/vendor/prometheus_client/values.py
@@ -0,0 +1,139 @@
+import os
+from threading import Lock
+import warnings
+
+from .mmap_dict import mmap_key, MmapedDict
+
+
+class MutexValue:
+    """A float protected by a mutex."""
+
+    _multiprocess = False
+
+    def __init__(self, typ, metric_name, name, labelnames, labelvalues, help_text, **kwargs):
+        self._value = 0.0
+        self._exemplar = None
+        self._lock = Lock()
+
+    def inc(self, amount):
+        with self._lock:
+            self._value += amount
+
+    def set(self, value, timestamp=None):
+        with self._lock:
+            self._value = value
+
+    def set_exemplar(self, exemplar):
+        with self._lock:
+            self._exemplar = exemplar
+
+    def get(self):
+        with self._lock:
+            return self._value
+
+    def get_exemplar(self):
+        with self._lock:
+            return self._exemplar
+
+
+def MultiProcessValue(process_identifier=os.getpid):
+    """Returns a MmapedValue class based on a process_identifier function.
+
+    The 'process_identifier' function MUST comply with this simple rule:
+    when called in simultaneously running processes it MUST return distinct values.
+
+    Using a different function than the default 'os.getpid' is at your own risk.
+    """
+    files = {}
+    values = []
+    pid = {'value': process_identifier()}
+    # Use a single global lock when in multi-processing mode
+    # as we presume this means there is no threading going on.
+    # This avoids the need to also have mutexes in __MmapDict.
+    lock = Lock()
+
+    class MmapedValue:
+        """A float protected by a mutex backed by a per-process mmaped file."""
+
+        _multiprocess = True
+
+        def __init__(self, typ, metric_name, name, labelnames, labelvalues, help_text, multiprocess_mode='', **kwargs):
+            self._params = typ, metric_name, name, labelnames, labelvalues, help_text, multiprocess_mode
+            # This deprecation warning can go away in a few releases when removing the compatibility
+            if 'prometheus_multiproc_dir' in os.environ and 'PROMETHEUS_MULTIPROC_DIR' not in os.environ:
+                os.environ['PROMETHEUS_MULTIPROC_DIR'] = os.environ['prometheus_multiproc_dir']
+                warnings.warn("prometheus_multiproc_dir variable has been deprecated in favor of the upper case naming PROMETHEUS_MULTIPROC_DIR", DeprecationWarning)
+            with lock:
+                self.__check_for_pid_change()
+                self.__reset()
+                values.append(self)
+
+        def __reset(self):
+            typ, metric_name, name, labelnames, labelvalues, help_text, multiprocess_mode = self._params
+            if typ == 'gauge':
+                file_prefix = typ + '_' + multiprocess_mode
+            else:
+                file_prefix = typ
+            if file_prefix not in files:
+                filename = os.path.join(
+                    os.environ.get('PROMETHEUS_MULTIPROC_DIR'),
+                    '{}_{}.db'.format(file_prefix, pid['value']))
+
+                files[file_prefix] = MmapedDict(filename)
+            self._file = files[file_prefix]
+            self._key = mmap_key(metric_name, name, labelnames, labelvalues, help_text)
+            self._value, self._timestamp = self._file.read_value(self._key)
+
+        def __check_for_pid_change(self):
+            actual_pid = process_identifier()
+            if pid['value'] != actual_pid:
+                pid['value'] = actual_pid
+                # There has been a fork(), reset all the values.
+                for f in files.values():
+                    f.close()
+                files.clear()
+                for value in values:
+                    value.__reset()
+
+        def inc(self, amount):
+            with lock:
+                self.__check_for_pid_change()
+                self._value += amount
+                self._timestamp = 0.0
+                self._file.write_value(self._key, self._value, self._timestamp)
+
+        def set(self, value, timestamp=None):
+            with lock:
+                self.__check_for_pid_change()
+                self._value = value
+                self._timestamp = timestamp or 0.0
+                self._file.write_value(self._key, self._value, self._timestamp)
+
+        def set_exemplar(self, exemplar):
+            # TODO: Implement exemplars for multiprocess mode.
+            return
+
+        def get(self):
+            with lock:
+                self.__check_for_pid_change()
+                return self._value
+
+        def get_exemplar(self):
+            # TODO: Implement exemplars for multiprocess mode.
+            return None
+
+    return MmapedValue
+
+
+def get_value_class():
+    # Should we enable multi-process mode?
+    # This needs to be chosen before the first metric is constructed,
+    # and as that may be in some arbitrary library the user/admin has
+    # no control over we use an environment variable.
+    if 'prometheus_multiproc_dir' in os.environ or 'PROMETHEUS_MULTIPROC_DIR' in os.environ:
+        return MultiProcessValue()
+    else:
+        return MutexValue
+
+
+ValueClass = get_value_class()
diff --git a/zhmc_prometheus_exporter/zhmc_prometheus_exporter.py b/zhmc_prometheus_exporter/zhmc_prometheus_exporter.py
index 801c5846..807e95fa 100755
--- a/zhmc_prometheus_exporter/zhmc_prometheus_exporter.py
+++ b/zhmc_prometheus_exporter/zhmc_prometheus_exporter.py
@@ -37,10 +37,11 @@
 import yaml
 import jsonschema
 import zhmcclient
-from prometheus_client import start_http_server
-from prometheus_client.core import GaugeMetricFamily, CounterMetricFamily, \
-    REGISTRY
 
+from .vendor.prometheus_client import start_http_server
+from .vendor.prometheus_client.core import GaugeMetricFamily, \
+    CounterMetricFamily, REGISTRY
+from .vendor import prometheus_client_version
 from ._version import __version__
 
 __all__ = []
@@ -273,8 +274,10 @@ def print_version():
     """
     # pylint: disable=no-member
     print("zhmc_prometheus_exporter version: {}\n"
-          "zhmcclient version: {}".
-          format(__version__, zhmcclient.__version__))
+          "zhmcclient version: {}\n"
+          "prometheus_client (vendored) version: {}".
+          format(__version__, zhmcclient.__version__,
+                 prometheus_client_version))
 
 
 def help_creds():


Test patch:
diff --git a/tests/test_all.py b/tests/test_all.py
index 1aac28c2..c611a01d 100644
--- a/tests/test_all.py
+++ b/tests/test_all.py
@@ -28,8 +28,8 @@
 import pytest
 import zhmcclient
 import zhmcclient_mock
-import prometheus_client
 
+from zhmc_prometheus_exporter.vendor import prometheus_client
 from zhmc_prometheus_exporter import zhmc_prometheus_exporter