mirror of
https://github.com/ets-labs/python-dependency-injector.git
synced 2024-11-22 17:47:02 +03:00
43 lines
1.6 KiB
ReStructuredText
43 lines
1.6 KiB
ReStructuredText
External dependency providers
|
|
-----------------------------
|
|
|
|
.. currentmodule:: dependency_injector.providers
|
|
|
|
:py:class:`ExternalDependency` provider can be useful for development of
|
|
self-sufficient libraries / modules / applications that has required external
|
|
dependencies.
|
|
|
|
For example, you have created self-sufficient library / module / application,
|
|
that has dependency on *database connection*.
|
|
|
|
Second step you want to do is to make this software component to be easy
|
|
reusable by wide amount of developers and to be easily integrated into many
|
|
applications.
|
|
|
|
It may be good idea, to move all external dependencies (like
|
|
*database connection*) to the top level and make them to be injected on your
|
|
software component's initialization. It will make third party developers feel
|
|
themselves free about integration of yours component in their applications,
|
|
because they would be able to find right place / right way for doing this
|
|
in their application's architectures.
|
|
|
|
At the same time, you can be sure, that your external dependency will be
|
|
satisfied with appropriate instance.
|
|
|
|
Example:
|
|
|
|
.. note::
|
|
|
|
Class ``UserService`` is a part of some library. ``UserService`` has
|
|
dependency on database connection, which can be satisfied with any
|
|
DBAPI 2.0 database connection. Being a self-sufficient library,
|
|
``UserService`` doesn't hardcode any kind of database management logic.
|
|
Instead of this, ``UserService`` has external dependency, that has to
|
|
be satisfied by cleint's code, out of library's scope.
|
|
|
|
.. image:: /images/providers/external_dependency.png
|
|
|
|
.. literalinclude:: ../../examples/providers/external_dependency.py
|
|
:language: python
|
|
:linenos:
|