iopipe 1.10.2
IOpipe agent for serverless Application Performance Monitoring

IOpipe Analytics & Distributed Tracing Agent for Python
=======================================================

`Build Status <https://circleci.com/gh/iopipe/iopipe-python>`__ `Code
Coverage <https://codecov.io/gh/iopipe/iopipe-python>`__ `PyPI
Version <https://badge.fury.io/py/iopipe>`__ `Apache
2.0 <https://github.com/iopipe/iopipe-python/blob/master/LICENSE>`__
`Slack <https://iopipe.now.sh>`__

This package provides analytics and distributed tracing for event-driven
applications running on AWS Lambda.

-  `Installation <https://github.com/iopipe/iopipe-python#installation>`__
-  `Usage <https://github.com/iopipe/iopipe-python#usage>`__

   -  `Configuration <https://github.com/iopipe/iopipe-python#configuration>`__
   -  `Reporting
      Exceptions <https://github.com/iopipe/iopipe-python#reporting-exceptions>`__
   -  `Custom
      Metrics <https://github.com/iopipe/iopipe-python#custom-metrics>`__
   -  `Labels <https://github.com/iopipe/iopipe-python#labels>`__
   -  `Core
      Agent <https://github.com/iopipe/iopipe-python#core-agent>`__
   -  `Disabling
      Reporting <https://github.com/iopipe/iopipe-python#disabling-reporting>`__
   -  `Step
      Functions <https://github.com/iopipe/iopipe-python#step-functions>`__

-  `Plugins <https://github.com/iopipe/iopipe-python#plugins>`__

   -  `Event Info
      Plugin <https://github.com/iopipe/iopipe-python#event-info-plugin>`__
   -  `Logger
      Plugin <https://github.com/iopipe/iopipe-python#logger-plugin>`__
   -  `Profiler
      Plugin <https://github.com/iopipe/iopipe-python#profiler-plugin>`__
   -  `Trace
      Plugin <https://github.com/iopipe/iopipe-python#trace-plugin>`__

      -  `Auto DB
         Tracing <https://github.com/iopipe/iopipe-python#auto-db-tracing>`__
      -  `Auto HTTP
         Tracing <https://github.com/iopipe/iopipe-python#auto-http-tracing>`__

   -  `Creating
      Plugins <https://github.com/iopipe/iopipe-python#creating-plugins>`__

-  `Supported Python
   Versions <https://github.com/iopipe/iopipe-python#supported-python-versions>`__
-  `Lambda
   Layers <https://github.com/iopipe/iopipe-python#lambda-layers>`__
-  `Framework
   Integration <https://github.com/iopipe/iopipe-python#framework-integration>`__

   -  `Chalice <https://github.com/iopipe/iopipe-python#chalice>`__
   -  `Serverless <https://github.com/iopipe/iopipe-python#serverless>`__
   -  `Zappa <https://github.com/iopipe/iopipe-python#zappa>`__
   -  `Accessing
      Context <https://github.com/iopipe/iopipe-python#accessing-context>`__

-  `Contributing <https://github.com/iopipe/iopipe-python#contributing>`__
-  `Running
   Tests <https://github.com/iopipe/iopipe-python#running-tests>`__
-  `License <https://github.com/iopipe/iopipe-python#license>`__

Installation
------------

We expect you will import this library into an existing (or new) Python
project intended to be run on AWS Lambda. On Lambda, functions are
expected to include module dependencies within their project paths, thus
we use ``-t $PWD``. Users building projects with a requirements.txt file
may simply add ``iopipe`` to their dependencies.

From your project directory:

.. code:: bash

   $ pip install iopipe -t .

   # If running locally or in other environments _besides_ AWS Lambda:
   $ pip install iopipe[local] -t .

Your folder structure for the function should look similar to:

::

   index.py # contains your lambda handler
     /iopipe
       - __init__.py
       - iopipe.py
     /requests
       - __init__.py
       - api.py
       - ...

Installation of the requests library is necessary for local dev/test,
but not when running on AWS Lambda as this library is part of the
default environment via the botocore library.

More details about lambda deployments are available in the `AWS
documentation <https://docs.aws.amazon.com/lambda/latest/dg/lambda-python-how-to-create-deployment-package.html>`__.

Usage
-----

Simply use our decorator to report metrics:

.. code:: python

   from iopipe import IOpipe

   iopipe = IOpipe('your project token here')

   @iopipe
   def handler(event, context):
       pass

The agent comes preloaded with the `Event
Info <https://github.com/iopipe/iopipe-python#event-info-plugin>`__,
`Profiler <https://github.com/iopipe/iopipe-python#profiler-plugin>`__
and `Trace <https://github.com/iopipe/iopipe-python#trace-plugin>`__
plugins. See the relevant plugin sections for usage.

Configuration
~~~~~~~~~~~~~

The following may be set as kwargs to the IOpipe class initializer:

``token`` (string: required)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Your IOpipe project token. If not supplied, the environment variable
``$IOPIPE_TOKEN`` will be used if present. `Find your project
token <https://dashboard.iopipe.com/install>`__

``debug`` (bool: optional = False)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Debug mode will log all data sent to IOpipe servers. This is also a good
way to evaluate the sort of data that IOpipe is receiving from your
application. If not supplied, the environment variable ``IOPIPE_DEBUG``
will be used if present.

``enabled`` (bool: optional = True)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Conditionally enable/disable the agent. For example, you will likely
want to disabled the agent during development. The environment variable
``$IOPIPE_ENABLED`` will also be checked.

``network_timeout`` (int: optional = 5000)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

The number of milliseconds IOpipe will wait while sending a report
before timing out. If not supplied, the environment variable
``$IOPIPE_NETWORK_TIMEOUT`` will be used if present.

``timeout_window`` (int: optional = 150)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

By default, IOpipe will capture timeouts by exiting your function 150
milliseconds early from the AWS configured timeout, to allow time for
reporting. You can disable this feature by setting ``timeout_window`` to
``0`` in your configuration. If not supplied, the environment variable
``$IOPIPE_TIMEOUT_WINDOW`` will be used if present.

Reporting Exceptions
~~~~~~~~~~~~~~~~~~~~

The IOpipe decorator will automatically catch, trace and reraise any
uncaught exceptions in your function. If you want to trace exceptions
raised in your case, you can use the ``.error(exception)`` method. This
will add the exception to the current report.

.. code:: python

   from iopipe import IOpipe

   iopipe = IOpipe()

   # Example 1: uncaught exceptions

   @iopipe
   def handler(event, context):
       raise Exception('This exception will be added to the IOpipe report automatically')

   # Example 2: caught exceptions

   @iopipe
   def handler(event, context):
       try:
           raise Exception('This exception is being caught by your function')
       except Exception as e:
           # Makes sure the exception is added to the report
           context.iopipe.error(e)

It is important to note that a report is sent to IOpipe when ``error()``
is called. So you should only record exceptions this way for failure
states. For caught exceptions that are not a failure state, it is
recommended to use custom metrics (see below).

Custom Metrics
~~~~~~~~~~~~~~

You can log custom values in the data sent upstream to IOpipe using the
following syntax:

.. code:: python

   from iopipe import IOpipe

   iopipe = IOpipe()

   @iopipe
   def handler(event, context):
       # the name of the metric must be a string
       # numerical (int, long, float) and string types supported for values
       context.iopipe.metric('my_metric', 42)

Metric key names are limited to 128 characters, and string values are
limited to 1024 characters.

Labels
~~~~~~

Label invocations sent to IOpipe by calling the ``label`` method with a
string (limit of 128 characters):

.. code:: python

   from iopipe import IOpipe

   iopipe = IOpipe()

   @iopipe
   def handler(event, context):
       # the name of the label must be a string
       context.iopipe.label('this-invocation-is-special')

Core Agent
~~~~~~~~~~

By default, the IOpipe agent comes pre-loaded with all the bundled
plugins in ``iopipe.contrib.*``. If you prefer to run the agent without
plugins or configure which plugins are used, you can use ``IOpipeCore``:

.. code:: python

   from iopipe import IOpipeCore
   from iopipe.contrib.trace import TracePlugin

   # Load IOpipe with only the trace plugin
   iopipe = IOpipeCore(plugins=[TracePlugin()])

   @iopipe
   def handler(event, context):
       pass

Disabling Reporting
~~~~~~~~~~~~~~~~~~~

You can programmatically disable IOpipe reporting for a single
invocation using the ``disable`` method:

.. code:: python

   from iopipe import IOpipe

   iopipe = IOpipe()

   @iopipe
   def handler(event, context):
       if some_condition:
           context.iopipe.disable()

Reporting will be re-enabled on the next invocation.

Step Functions
~~~~~~~~~~~~~~

IOpipe is compatible with AWS Lambda step functions. To enable step
function tracing:

.. code:: python

   from iopipe import IOpipe

   iopipe = IOpipe()

   @iopipe.step
   def handler(event, context):
       pass

The ``@iopipe.step`` decorator will enable step function mode, which
will collect additional meta data about your step functions.

Plugins
-------

IOpipe’s functionality can be extended through plugins. Plugins hook
into the agent lifecycle to allow you to perform additional analytics.

Event Info Plugin
~~~~~~~~~~~~~~~~~

The IOpipe agent comes bundled with an event info plugin that
automatically extracts useful information from the ``event`` object and
creates custom metrics for them.

Here’s an example of how to use the event info plugin:

.. code:: python

   from iopipe import IOpipe
   from iopipe.contrib.eventinfo import EventInfoPlugin

   iopipe = IOpipe(plugins=[EventInfoPlugin()])

   @iopipe
   def handler(event, context):
       # do something here

When this plugin is installed, custom metrics will be created
automatically for the following event source data:

-  API Gateway
-  ALB
-  Alexa Skill Kit
-  CloudFront
-  Kinesis
-  Kinesis Firehose
-  S3
-  SES
-  SNS
-  SQS
-  Scheduled Events

Now in your IOpipe invocation view you will see useful event
information.

Logger Plugin
~~~~~~~~~~~~~

**Note:** This plugin is in beta. Want to give it a try? Find us on
`Slack <https://iopipe.now.sh>`__.

The IOpipe agent comes bundled with a logger plugin that allows you to
attach IOpipe to the ``logging`` module so that you can see your log
messages in the IOpipe dashboard.

Here’s an example of how to use the logger plugin:

.. code:: python

   from iopipe import IOpipe
   from iopipe.contrib.logger import LoggerPlugin

   iopipe = IOpipe(plugins=[LoggerPlugin(enabled=True)])

   @iopipe
   def handler(event, context):
       context.iopipe.log.info('Handler has started execution')

Since this plugin adds a handler to the ``logging`` module, you can use
``logging`` directly as well:

.. code:: python

   import logging

   from iopipe import IOpipe
   from iopipe.contrib.logger import LoggerPlugin

   iopipe = IOpipe(plugins=[LoggerPlugin(enabled=True)])
   logger = logging.getLogger()

   @iopipe
   def handler(event, context):
       logger.error('Uh oh')

You can also specify a log name, such as if you only wanted to log
messages for ``mymodule``:

.. code:: python

   from iopipe import IOpipe
   from iopipe.contrib.logger import LoggerPlugin

   iopipe = IOpipe(plugins=[LoggerPlugin('mymodule', enabled=True)])

This would be equivalent to ``logging.getLogger('mymodule')``.

By default the logger plugin is disabled. You must explicitly set
``enabled=True`` when instantiating or use the ``IOPIPE_LOGGER_ENABLED``
environment variable to enable it.

The default logger plugin log level is ``logging.INFO``, but it can be
set like this:

.. code:: python

   import logging

   from iopipe import IOpipe
   from iopipe.contrib.logger import LoggerPlugin

   iopipe = IOpipe(plugins=[LoggerPlugin(enabled=True, level=logging.DEBUG)])

Putting IOpipe into ``debug`` mode also sets the log level to
``logging.DEBUG``.

The logger plugin also redirects stdout by default, so you can do the
following:

.. code:: python

   from iopipe import IOpipe
   from iopipe.contrib.logger import LoggerPlugin

   iopipe = IOpipe(plugins=[LoggerPlugin(enabled=True)])

   @iopipe
   def handler(event, context):
       print('I will be logged')

Now in your IOpipe invocation view you will see log messages for that
invocation.

If you prefer your print statements not to be logged, you can disable
this by setting ``redirect_stdout`` to ``False``:

.. code:: python

   iopipe = IOpipe(plugins=[LoggerPlugin(enabled=True, redirect_stdout=False)])

**Note:** Due to a change to the way the python3.7 runtime configures
logging, stdout redirection is disabled for this runtime. Use
``context.iopipe.log.*`` instead.

By default the logger plugin will log messages to an in-memory buffer.
If you prefer to log messages to your Lambda function’s ``/tmp``
directory:

.. code:: python

   iopipe = IOpipe(plugins=[LoggerPlugin(enabled=True, use_tmp=True)])

With ``use_tmp`` enabled, the plugin will automatically delete log files
written to ``/tmp`` after each invocation.

Profiler Plugin
~~~~~~~~~~~~~~~

The IOpipe agent comes bundled with a profiler plugin that allows you to
profile your functions with
`cProfile <https://docs.python.org/3/library/profile.html#module-cProfile>`__.

Here’s an example of how to use the profiler plugin:

.. code:: python

   from iopipe import IOpipe
   from iopipe.contrib.profiler import ProfilerPlugin

   iopipe = IOpipe(plugins=[ProfilerPlugin()])

   @iopipe
   def handler(event, context):
       # do something here

By default the plugin will be disabled and can be enabled at runtime by
setting the ``IOPIPE_PROFILER_ENABLED`` environment variable to
``true``/``True``.

If you want to enable the plugin for all invocations:

.. code:: python

   iopipe = IOpipe(plugins=[ProfilerPlugin(enabled=True)])

Now in your IOpipe invocation view you will see a “Profiling” section
where you can download your profiling report.

Once you download the report you can open it using pstat’s interactive
browser with this command:

.. code:: bash

   python -m pstats <file here>

Within the pstats browser you can sort and restrict the report in a
number of ways, enter the ``help`` command for details. Refer to the
`pstats
Documentation <https://docs.python.org/3/library/profile.html#module-pstats>`__.

Trace Plugin
~~~~~~~~~~~~

The IOpipe agent comes bundled with a trace plugin that allows you to
perform tracing.

Here’s an example of how to use the trace plugin:

.. code:: python

   from iopipe import IOpipe
   from iopipe.contrib.trace import TracePlugin

   iopipe = IOpipe(plugins=[TracePlugin()])

   @iopipe
   def handler(event, context):
       context.iopipe.mark.start('expensive operation')
       # do something here
       context.iopipe.mark.end('expensive operation')

Or you can use it as a context manager:

.. code:: python

   from iopipe import IOpipe

   iopipe = IOpipe()

   @iopipe
   def handler(event, context):
       with context.iopipe.mark('expensive operation'):
           # do something here

Or you can use it as a decorator:

.. code:: python

   from iopipe import IOpipe

   iopipe = IOpipe()

   @iopipe
   def handler(event, context):
       @context.iopipe.mark.decorator('expensive operation'):
       def expensive_operation():
           # do something here

       expensive_operation()

Any block of code wrapped with ``start`` and ``end`` or using the
context manager or decorator will be traced and the data collected will
be available on your IOpipe dashboard.

By default, the trace plugin will auto-measure any trace you make. But
you can disable this by setting ``auto_measure`` to ``False``:

.. code:: python

   from iopipe import IOpipe
   from iopipe.contrib.trace import TracePlugin

   iopipe = IOpipe(plugins=[TracePlugin(auto_measure=False)])

   @iopipe
   def handler(event, context):
       with context.iopipe.mark('expensive operation'):
           # do something here

       # Manually measure the trace
       context.iopipe.mark.measure('expensive operation')

Auto DB Tracing
^^^^^^^^^^^^^^^

The trace plugin can trace your database requests automatically. To
enable this feature, set ``auto_db`` to ``True`` or set the
``IOPIPE_TRACE_AUTO_DB_ENABLED`` environment variable. For example:

.. code:: python

   iopipe = IOpipe(plugins=[TracePlugin(auto_db=True)])

With ``auto_db`` enabled, you will see traces for any database requests
you make within your function on your IOpipe dashboard. Currently this
feature supports
`MongoDB <https://github.com/mongodb/mongo-python-driver>`__,
`MySQL <https://github.com/PyMySQL>`__,
`PostgreSQL <https://github.com/psycopg/psycopg2>`__ and
`Redis <https://github.com/andymccurdy/redis-py>`__.

MongoDB example:

.. code:: python

   from iopipe import IOpipe
   from pymongo import MongoClient

   iopipe = IOpipe(plugins=[TracePlugin(auto_db=True)])

   @iopipe
   def handler(event, context):
       client = MongoClient("your-host-here", 27017)

       db = client.test
       db.my_collection.insert_one({"x": 10})
       db.my_collection.find_one()

Redis example:

.. code:: python

   from iopipe import IOpipe
   from redis import Redis

   iopipe = IOpipe(plugins=[TracePlugin(auto_db=True)])

   @iopipe
   def handler(event, context):
       r = redis.Redis(host="your-host-here", port=6379, db=0)
       r.set("foo", "bar")
       r.get("foo")

Auto HTTP Tracing
^^^^^^^^^^^^^^^^^

The trace plugin can trace your HTTP/HTTPS requests automatically. To
enable this feature, set ``auto_http`` to ``True`` or set the
``IOPIPE_TRACE_AUTO_HTTP_ENABLED`` environment variable. For example:

.. code:: python

   iopipe = IOpipe(plugins=[TracePlugin(auto_http=True)])

With ``auto_http`` enabled, you will see traces for any HTTP/HTTPS
requests you make within your function on your IOpipe dashboard.
Currently this feature only supports the ``requests`` library, including
``boto3`` and ``botocore`` support.

To filter which HTTP requests are traced use ``http_filter``:

.. code:: python

   def http_filter(request, response):
       if request['url'].startswith('https://www.iopipe.com'):
           # Exceptions raised will delete the trace
           raise Exception(Do not trace this URL')
       # You can also remove data from the trace
       response['headers'].pop('Content-Type', None)
       return request, response

   iopipe = IOpipe(plugins=[TracePlugin(auto_http=True, http_filter=http_filter)])

To add additional HTTP headers to your ttrace data use ``http_headers``:

.. code:: python

   http_headers = ['Cache-Control', 'Etag']

   iopipe = IOpipe(plugins=[TracePlugin(auto_http=True, http_headers=http_headers)

.. _plugins-1:

Plugins
-------

Creating Plugins
~~~~~~~~~~~~~~~~

To create an IOpipe plugin you must implement the
``iopipe.plugins.Plugin`` interface.

Here is a minimal example:

.. code:: python

   from iopipe.plugins import Plugin


   class MyPlugin(Plugin):
       name = 'my-plugin'
       version = '0.1.0'
       homepage = 'https://github.com/iopipe/my-plugin/'
       enabled = True

       def pre_setup(self, iopipe):
           pass

       def post_setup(self, iopipe):
           pass

       def pre_invoke(self, event, context):
           pass

       def post_invoke(self, event, context):
           pass

       def post_response(self, response):
           pass

       def pre_report(self, report):
           pass

       def post_report(self):
           pass

As you can see, this plugin doesn’t do much. If you want to see a
functioning example of a plugin check out the trace plugin at
``iopipe.contrib.trace.plugin.TracePlugin``.

Plugin Properties
^^^^^^^^^^^^^^^^^

A plugin has the following properties defined:

-  ``name``: The name of the plugin, must be a string.
-  ``version``: The version of the plugin, must be a string.
-  ``homepage``: The URL of the plugin’s homepage, must be a string.
-  ``enabled``: Whether or not the plugin is enabled, must be a boolean.

Plugin Methods
^^^^^^^^^^^^^^

A plugin has the following methods defined:

-  ``pre_setup``: Is called once prior to the agent initialization; is
   passed the ``iopipe`` instance.
-  ``post_setup``: Is called once after the agent is initialized; is
   passed the ``iopipe`` instance.
-  ``pre_invoke``: Is called prior to each invocation; is passed the
   ``event`` and ``context`` of the invocation.
-  ``post_invoke``: Is called after each invocation; is passed the
   ``event`` and ``context`` of the invocation.
-  ``post_response``: Is called after the invocation response; is passed
   the ``response``\ value.
-  ``pre_report``: Is called prior to each report being sent; is passed
   the ``report`` instance.
-  ``post_report``: Is called after each report is sent; is passed the
   ``report`` instance.

Supported Python Versions
-------------------------

This package supports Python 2.7, 3.6 and 3.7, the runtimes supported by
AWS Lambda.

Lambda Layers
-------------

IOpipe publishes `AWS Lambda
Layers <https://docs.aws.amazon.com/lambda/latest/dg/configuration-layers.html>`__
which are publicly available on AWS. Using a framework that supports
lambda layers (such as SAM or Serverless), you can use the following
ARNs for your runtime:

-  python3.6, python3.7:
   ``arn:aws:lambda:$REGION:146318645305:layer:IOpipePython:$VERSION_NUMBER``
-  python2.7:
   ``arn:aws:lambda:$REGION:146318645305:layer:IOpipePython27:$VERSION_NUMBER``

Where ``$REGION`` is your AWS region and ``$VERSION_NUMBER`` is an
integer representing the IOpipe release. You can get the version number
via the `Releases <https://github.com/iopipe/iopipe-python/releases>`__
page.

Then in your SAM template (for example), you can add:

.. code:: yaml

   Globals:
     Function:
       Layers:
           - arn:aws:lambda:us-east-1:146318645305:layer:IOpipePython:1

And the IOpipe library will be included in your function automatically.

You can also wrap your IOpipe functions without a code change using
layers. For example, in your SAM template you can do the following:

.. code:: yaml

   Resources:
     YourFunctionere:
       Type: 'AWS::Serverless::Function'
       Properties:
         CodeUri: path/to/your/code
         # Automatically wraps the handler with IOpipe
         Handler: iopipe.handler.wrapper
         Runtime: python3.6
         Environment:
           Variables:
             # Specifies which handler IOpipe should run
             IOPIPE_HANDLER: path.to.your.handler
             IOPIPE_TOKEN: 'your token here'

We also have an `example
app <https://github.com/iopipe/iopipe-python/tree/master/acceptance/serverless-layers>`__
using layers with Serverless. It also demonstrates how to use layers
without a code change.

**NEW:** We have also released a `Serverless
Plugin <https://www.github.com/iopipe/serverless-iopipe-layers>`__ to do
all this for you automatically.

Framework Integration
---------------------

IOpipe integrates with popular serverless frameworks. See below for
examples. If you don’t see a framework you’d like to see supported,
please create an issue.

Chalice
~~~~~~~

Using IOpipe with the `Chalice <https://github.com/aws/chalice>`__
framework is easy. Wrap your ``app`` like so:

.. code:: python

   from chalice import Chalice
   from iopipe import IOpipe

   iopipe = IOpipe()

   app = Chalice(app_name='helloworld')

   @app.route('/')
   def index():
       return {'hello': 'world'}

   # Do this after defining your routes
   app = iopipe(app)

Serverless
~~~~~~~~~~

Using IOpipe with
`Serverless <https://github.com/serverless/serverless>`__ is easy.

First, we highly recommend the
`serverless-python-requirements <https://github.com/UnitedIncome/serverless-python-requirements>`__
plugin:

.. code:: bash

   $ npm install --save-dev serverless-python-requirements

This plugin will add ``requirements.txt`` support to Serverless. Once
installed, add the following to your ``serverless.yml``:

.. code:: yaml

   plugins:
     - serverless-python-requirements

Then add ``iopipe``\ to your ``requirements.txt``:

.. code:: bash

   $ echo "iopipe" >> requirements.txt

Now Serverless will ``pip install -r requirements.txt`` when packaging
your functions.

Keep in mind you still need to add the ``@iopipe`` decorator to your
functions. See `Usage <https://github.com/iopipe/iopipe-python#usage>`__
for details.

Be sure to check out the
`serverless-python-requirements <https://github.com/UnitedIncome/serverless-python-requirements>`__
``README`` as the plugin has a number of useful features for compiling
AWS Lambda compatible Python packages.

If you’re using the
`serverless-wsgi <https://github.com/logandk/serverless-wsgi>`__ plugin,
you will need to wrap the wsgi handler it bundles with your function.

The easiest way to do this is to create a ``wsgi_wrapper.py`` module in
your project’s root with the following:

.. code:: python

   import imp

   from iopipe import IOpipe

   wsgi = imp.load_source('wsgi', 'wsgi.py')

   iopipe = IOpipe()
   handler = iopipe(wsgi.handler)

Then in your ``serverless.yml``, instead of this:

.. code:: yaml

   functions:
     api:
       handler: wsgi.handler
       ...

Use this:

.. code:: yaml

   functions:
     api:
       handler: wsgi_wrapper.handler
       ...

Zappa
~~~~~

Using IOpipe with `Zappa <https://github.com/Miserlou/Zappa>`__ is easy.
In your project add the following:

.. code:: python

   from iopipe import IOpipe
   from zappa.handler import lambda_handler

   iopipe = IOpipe()
   lambda_handler = iopipe(lambda_handler)

Then in your ``zappa_settings.json`` file include the following:

.. code:: js

   {
     "lambda_handler": "module.path.to.lambda_handler"
   }

Where ``module-path.to.lambda_handler`` is the Python module path to the
``lambda_handler`` you created above. For example, if you put it in
``myproject/__init__.py`` the path would be
``myproject.lambda_handler``.

Accessing Context
~~~~~~~~~~~~~~~~~

If the framework you’re using makes it non-trivial to access the Lamba
context, you can use ``iopipe.context``. The ``iopipe.context`` is
``None`` if outside of an invocation.

.. code:: python

   from iopipe import IOpipe

   iopipe = IOpipe()

   # Be sure to check, can be None
   if iopipe.context:
       # do something with context

Contributing
------------

Contributions are welcome. We use the
`black <https://github.com/ambv/black>`__ code formatter.

.. code:: bash

   pip install black

We recommend using it with
`pre-commit <https://pre-commit.com/#install>`__:

.. code:: bash

   pip install pre-commit
   pre-commit install

Using these together will auto format your git commits.

Running Tests
-------------

If you have ``tox`` installed, you can run the Python 2.7 and 3.6 tests
with:

.. code:: bash

   tox

If you don’t have ``tox`` installed you can also run:

.. code:: bash

   python setup.py test

We also have make tasks to run tests in ``lambci/lambda:build-python``
Docker containers:

.. code:: bash

   make test

License
-------

Apache 2.0