Package: xeno
xeno: The Python dependency injector from outer space.xenoat its core is a simple Python dependency injection framework. Use it when
you need to manage complex inter-object dependencies in a clean way. For the
merits of dependency injection and IOC, seehttps://en.wikipedia.org/wiki/Dependency_injection.xenoshould feel pretty familiar to users of Google Guice in Java, as it
is somewhat similar, although it is less focused on type names and more
on named resources and parameter injection.xenoalso offersxeno.build, a build automation framework built atop the core
dependency injection inspired byInvoke.  It is
intended to come with batteries-included tools for making C/C++ projects,
executing shell scripts, batching, and more.  It is built on the concept of
composable "recipes", which are generic instructions for building different
types of filesystem targets.InstallationInstallation is simple. With python3-pip, do the following:$ sudo pip install -e .Or, to install the latest version available on PyPI:$ sudo pip install xenoUsageAs a build automation frameworkTo usexeno.buildto build a simple C software project, first create a file
calledbuild.pyin your repo (it can be called anything, but this is
customary).  Follow this template example for guidance:#!/usr/bin/env python3
from xeno.build import *

# TODO: Add recipes, providers, and tasks here.

build()Then, you can import thecompilerecipe fromxeno.recipes.c:from xeno.recipes.c import compile, ENVENVhere is the default environment variables thatcompilewill use by
default.  It defaults to usingclangto compile C projects, you can change
that here, and you can add additional compile-time flags.  TheENVobject is
of typexeno.shell.Environment, which allows for some complex shlex-based
joining and recombining of flags, such that you can additively compose the
enviornment with defaults and/or what may be specified outside the build script.
You can also provide your own environment variables via theenv=parameter tocompile.ENV['CC'] = 'gcc'
ENV += dict(
    LDFLAGS='-g'
)Let's create a provider that lists all of our source files and another that
lists our headers.  This will be useful for defining our tasks and using thecompilerecipe.from pathlib import Path

@provide
def source_files():
    return Path.cwd().glob("src/*.c")

@provide
def header_files():
    return Path.cwd().glob("include/*.h")Next, let's define a single default task that builds our program.@task(default=True)
def executable(source_files, header_files):
    return compile(source_files, target="my_program", headers=header_files)compilecan take iterables of source files and/or combinations of strings and
lists in*args.  In this case, we elected to specify a target name for the
program.  If this wasn't the case, the name of the resulting target would be
based on the name of the first source file.  This is ideal if there is only one
source being provided or if the main source file is always provided first and is
the desired name of the executable, but in this case it would be whatever came
first in the directory order which isn't deterministic or ideal.Specifying theheaders=parameter here links the recipe to our header files
as static file dependencies.  If these files change, the recipe is acknowledged
to beoutdated, and will be rebuilt the next time the build script is run even
if an executable target already exists.That's it!  Let's put it all together, and then we'll have a build script for
our program.#!/usr/bin/env python3
from xeno.build import *
from xeno.recipes.c import compile, ENV
from pathlib import Path

ENV['CC'] = 'gcc'
ENV += dict(
    LDFLAGS='-g'
)

@provide
def source_files():
    return Path.cwd().glob("src/*.c")

@provide
def header_files():
    return Path.cwd().glob("include/*.h")

build()Mark this script as executable and run it as./build.py, or usepython build.py.  Be sure to check out./build.py --helpfor a list of command line
options and running modes.xeno.buildis smart and can create addressable
targets from a variety of different nested recipe construction scenarios, so
build more complex scripts and try out./build.py -Lto see them all!Watch this space for more in-depth documentation to come in the near future.As an IOC frameworkTo usexenoas a dependency injection framework, you need to create a
xeno.Injector and provide it with modules. These modules are regular
Python objects with methods marked with the@xeno.providerannotation. This annotation tells theInjectorthat this method
provides a named resource, the same name as the method marked with@provider. These methods should either take no parameters (other
thanself), or take named parameters which refer to other resources
by name, i.e. the providers can also be injected with other resources in
order to build a dependency chain.Once you have anInjectorfull of resources, you can use it to
inject instances, functions, or methods with resources.To create a new object instance by injecting resources into its
constructor, useInjector.create(clazz), whereclazzis the
class which you would like to instantiate. The constructor of this class
is called, and all named parameters in the constructor are treated as
resource references. Once the object is instantiated, any methods marked
with@injectare invoked with named resources provided.Resources can be injected into normal functions, bound methods, or
existing object instances viaInjector.inject(obj). If the parameter
is an object instance, it is scanned for methods marked with@injectand these methods are invoked with named resources provided.ExampleIn this simple example, we inject an output stream into an object.import sys
from xeno import *

class OutputStreamModule:
   @provide
   def output_stream(self):
      return sys.stdout

class VersionWriter:
   def __init__(self, output_stream):
      self.output_stream = output_stream

   def write_version(self):
      print('The python version is %s' % sys.version_info,
            file=self.output_stream)

injector = Injector(OutputStreamModule())
writer = injector.create(VersionWriter)
writer.write_version()Checkouttest.pyin the git repo for more usage examples.Change LogVersion 7.3.0: Oct 9 2023xeno.buildtargets can now receive arguments!  All args after a lone '@' arg are packed into an
implicitargvresource that can be injected into targets automatically.Fixed brokenrun_asfunctionality inShellRecipe.Version 7.2.2: Oct 7 2023Add a**kwargspass-thru forxeno.shell.check()for passing args tosubprocess.check_output().Version 7.2.1: Sep 15 2023Allow recipe factories to return empty results as None (or no explicit return value).Version 7.2.0: Sep 15 2023Improvements to the busy spinner: it now loops through pending recipe sigils
to let the user know what is blocking in the build.Improved xeno.recipes.checkout() now opensbuild.pyand checks its Python AST
for references to "xeno" before trying to run "./build.py deps" if "build.py"
is present in the resulting repository.Version 7.1.0: Sep 09 2023Add aupdate()override toxeno.shell.Environmentwhich takes
the same arguments asselect()but updates the dictionary in-place
instead of making and returning a new one.Version 7.0.0: Sep 09 2023Lift various build recipes from different projects into a
"batteries-included" set of build tools underxeno.recipes.**.New enriched focus on backwards compatibility between minor versons.Restructuring and refactoring,xeno.cookbookis deprecated.From now on, legacy features will be marked as deprecated and made to
continue to work until the next major version, during which they
will be removed.Version 4.12.0: Aug 07 2022Changes to support Python 3.10, older versions are now deprecated.Version 4.10.0: Oct 28 2021Allow recipes to be specified with glob-style wildcards, as perfnmatch.Version 4.9.0: Jan 03 2021Deprecate@recipefactory decorator for@factory.Allow recipes to specify asetuprecipe, which is not part
of the recipe inputs or outputs but is needed to fulfill the task.Version 4.8.0: Dec 29 2020All recipe resources are loaded before targets are determined.Recipe names are now valid targets for a build.Version 4.7.0: Dec 16 2020Fixed a bug where build would continue resolving with outdated results.Added@recipedecorator toxeno.buildto denote recipe functions.Version 4.4.0: Nov 2 2020Added experimentalxeno.buildmodule, a declarative build system driven by IOC.Addedxeno.coloroffering basic ANSI color and terminal control.Version 4.3.0: May 9 2020Allow methods to be decorated with@injector.provide, eliminating the need for modules
in some simple usage scenarios.Version 4.2.0: May 8 2020SplitInjectorintoAsyncInjectorandSyncInjectorto allow injection to be performed
in context of another event loop if async providers are not used.FixedAsyncInjectorto actually support asynchronous resolution of dependencies.Version 4.1.0: Feb 3 2020AddedInjector.get_ordered_dependenciesto get a breadth first list of
dependencies in the order they are built.Version 4.0.0: May 12 2019BACKWARDS INCOMPATIBLE CHANGERemoved support for parameter annotation aliases.  Use@aliason methods instead.
This was removed to allowxenocode to play nicely with PEP 484 type hinting.Version 3.1.0: August 29 2018Add ClassAttributes.for_object convenience methodVersion 3.0.0: May 4 2018BACKWARDS INCOMPATIBLE CHANGEProvide injection interceptors with an alias map for the given param map.This change breaks all existing injection interceptors until the new param is added.Version 2.8.0: May 3 2018Allow decorated/wrapped methods to be properly injected if their'params'method attribute
is carried forward.Version 2.7.0: April 20 2018TheInjectornow adds a'resource-name'attribute to resource methods allowing
the inspection of a resource's full canonical name at runtime.Version 2.6.0: March 27 2018Bugfix release: Remove support for implicit asynchronous resolution of
dependencies.  Providers can still be async, in order to await some other
set of coroutines, but can no longer themselves be run in sync.  The
benefits do not outweigh the complexity of bugs and timing concerns
introduced by this approach.Version 2.5.0: March 2, 2018AddedInjector.provide_async().  Note that resource are always run within an
event loop and should not useinject(),provide(), orrequire()directly, instead they should useinject_async(),provide_async(), andrequire_async()to dynamically modify resources.Version 2.4.1: January 30, 2018AddedInjector.scan_resources()to allow users to scan for resource names with the given attributes.AddedAttributes.merge()to assist with passing attributes down to functions which are wrapped in a decorator.AddedMethodAttributes.wraps()static decorator to summarize a common use case of attribute merging.AddedMethodAttributes.add()as a simple static decorator to add attribute values to a method's attributes.Version 2.4.0: January 21, 2018Dropped support for deprecatedNamespace.enumerate()in favor ofNamespace.get_leaves().Version 2.3.0: January 21, 2018Added support for asyncio-based concurrency and async provider coroutines with per-injector event loops (injector.loop).Version 2.2.0: September 19, 2017Expose the Injector's Namespace object viaInjector.get_namespace().  This is useful for users who want to list the contents of namespaces.Version 2.1.0: August 23rd, 2017Allow multiple resource names to be provided toInjector.get_dependency_graph().Version 2.0.0: July 25th, 2017BACKWARDS INCOMPATIBLE CHANGEChange the default namespace separator and breakout symbol to '/'Code using the old namespace separator can be made to work by overriding the value of xeno.Namespace.SEP:import xeno
xeno.Namespace.SEP = '::'Version 1.10: July 25th, 2017Allow names prefixed with::to escape their module's namespace, e.g.::top_level_itemVersion 1.9: May 23rd, 2017Add@const()module annotation for value-based resourcesAddInjector.get_dependency_tree()to fetch a tree of dependency names for a given resource name.Version 1.8: May 16th, 2017AddMissingResourceErrorandMissingDependencyErrorexception types.Version 1.7: May 16th, 2017Major update, adding support for namespaces, aliases, and inline resource parameter aliases.  See the unit tests in test.py for examples.Added@namespace('Name')decorator for modules to specify that all resources defined in the module should be scoped within 'Name::'.Added@name('alt-name')to allow resources to be named something other than the name of the function that defines them.Added@alias('alt-name', 'name')to allow a resource to be renamed within either the scope of a single resource or a whole module.Added@using('NamespaceName')to allow the contents of the given namespace
to be automatically aliases into either the scope of a single resource or
a whole module.Added support for resource function annotations via PEP 3107 to allow
inline aliases, e.g.def my_resource(name: 'Name::something-important'):Version 1.6: April 26th, 2017Changed howxeno.MethodAttributesworks: it now holds a map of attributes
and provides methodsget(),put(), andcheck()Version 1.5: April 26th, 2017Added injection interceptorsRefactored method tagging to usexeno.MethodAttributesinstead of named
object attributes to make attribute tagging more flexible and usable by
the outside world, e.g. for the new injectors.Version 1.4: August 30th, 2016Added cycle detection.Version 1.3: August 29th, 2016Have the injector offer itself as a named resource named 'injector'.