python-dependency-injector/README.rst
2016-05-20 13:33:39 +03:00

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Dependency Injector - Python dependency injection framework
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*Dependency Injector* is a Python dependency injection framework. It was
designed to be unified, developer-friendly tool for managing any kind
of Python objects and their dependencies in formal, pretty way.
*Dependency Injector* framework key features are:
+ Easy, smart, pythonic style.
+ Obvious, clear structure.
+ Extensibility and flexibility.
+ Memory efficiency.
+ Thread safety.
+ Documentation.
+ Semantic versioning.
Status
------
+---------------------------------------+----------------------------------------------------------------------------------------+
| *PyPi* | .. image:: https://img.shields.io/pypi/v/dependency_injector.svg |
| | :target: https://pypi.python.org/pypi/dependency_injector/ |
| | :alt: Latest Version |
| | .. image:: https://img.shields.io/pypi/dm/dependency_injector.svg |
| | :target: https://pypi.python.org/pypi/dependency_injector/ |
| | :alt: Downloads |
| | .. image:: https://img.shields.io/pypi/l/dependency_injector.svg |
| | :target: https://pypi.python.org/pypi/dependency_injector/ |
| | :alt: License |
+---------------------------------------+----------------------------------------------------------------------------------------+
| *Python versions and implementations* | .. image:: https://img.shields.io/pypi/pyversions/dependency_injector.svg |
| | :target: https://pypi.python.org/pypi/dependency_injector/ |
| | :alt: Supported Python versions |
| | .. image:: https://img.shields.io/pypi/implementation/dependency_injector.svg |
| | :target: https://pypi.python.org/pypi/dependency_injector/ |
| | :alt: Supported Python implementations |
+---------------------------------------+----------------------------------------------------------------------------------------+
| *Builds and tests coverage* | .. image:: https://travis-ci.org/ets-labs/python-dependency-injector.svg?branch=master |
| | :target: https://travis-ci.org/ets-labs/python-dependency-injector |
| | :alt: Build Status |
| | .. image:: https://coveralls.io/repos/ets-labs/python-dependency-injector/badge.svg |
| | :target: https://coveralls.io/r/ets-labs/python-dependency-injector |
| | :alt: Coverage Status |
+---------------------------------------+----------------------------------------------------------------------------------------+
Installation
------------
*Dependency Injector* library is available on PyPi_::
pip install dependency_injector
Example
-------
Brief example below demonstrates usage of *Dependency Injector* catalogs and
providers for definition of several IoC containers for some microservice
system that consists from several business and platform services:
.. code-block:: python
"""Example of several Dependency Injector catalogs."""
import sqlite3
import boto.s3.connection
import example.services
from dependency_injector import catalogs
from dependency_injector import providers
class Platform(catalogs.DeclarativeCatalog):
"""Catalog of platform service providers."""
database = providers.Singleton(sqlite3.connect, ':memory:')
s3 = providers.Singleton(boto.s3.connection.S3Connection,
aws_access_key_id='KEY',
aws_secret_access_key='SECRET')
class Services(catalogs.DeclarativeCatalog):
"""Catalog of business service providers."""
users = providers.Factory(example.services.Users,
db=Platform.database)
photos = providers.Factory(example.services.Photos,
db=Platform.database,
s3=Platform.s3)
auth = providers.Factory(example.services.Auth,
db=Platform.database,
token_ttl=3600)
Next example demonstrates usage of these IoC containers with the help of
``@inject`` decorator:
.. code-block:: python
"""Dependency Injector example."""
from dependency_injector.injections import inject
from catalogs import Services
@inject(users_service=Services.users)
@inject(auth_service=Services.auth)
@inject(photos_service=Services.photos)
def main(login, password, photo, users_service, auth_service, photos_service):
"""Main function."""
user = users_service.get_user(login)
auth_service.authenticate(user, password)
photos_service.upload_photo(user['id'], photo)
if __name__ == '__main__':
main(login='user', password='secret', photo='photo.jpg')
Also some alternative definition styles could be used. Like this one:
.. code-block:: python
class Platform(catalogs.DeclarativeCatalog):
"""Catalog of platform service providers."""
database = providers.Singleton(sqlite3.connect) \
.args(':memory:')
s3 = providers.Singleton(boto.s3.connection.S3Connection) \
.kwargs(aws_access_key_id='KEY',
aws_secret_access_key='SECRET')
or like this one:
.. code-block:: python
class Platform(catalogs.DeclarativeCatalog):
"""Catalog of platform service providers."""
database = providers.Singleton(sqlite3.connect)
database.args(':memory:')
s3 = providers.Singleton(boto.s3.connection.S3Connection)
s3.kwargs(aws_access_key_id='KEY',
aws_secret_access_key='SECRET')
You can get more *Dependency Injector* examples in ``/examples`` directory on
GitHub:
https://github.com/ets-labs/python-dependency-injector
Documentation
-------------
*Dependency Injector* documentation is hosted on ReadTheDocs:
- `User's guide`_
- `API docs`_
Feedback
--------
Feel free to post questions, bugs, feature requests, proposals etc. on
*Dependency Injector* GitHub Issues:
https://github.com/ets-labs/python-dependency-injector/issues
Your feedback is quite important!
.. _PyPi: https://pypi.python.org/pypi/dependency_injector
.. _User's guide: http://python-dependency-injector.ets-labs.org/en/stable/
.. _API docs: http://python-dependency-injector.ets-labs.org/en/stable/api/
.. _SLOC: http://en.wikipedia.org/wiki/Source_lines_of_code
.. _SOLID: http://en.wikipedia.org/wiki/SOLID_%28object-oriented_design%29
.. _IoC: http://en.wikipedia.org/wiki/Inversion_of_control
.. _dependency injection: http://en.wikipedia.org/wiki/Dependency_injection