Add new multiple containers example

docs/main/changelog.rst

@@ -7,6 +7,14 @@ that were made in every particular version.
 From version 0.7.6 *Dependency Injector* framework strictly 
 follows `Semantic versioning`_
 
+Development version
+-------------------
+- Add ``application-multiple-containers-runtime-overriding`` example. This example demonstrates
+  how to build application from multiple containers and override one container config from
+  another one in the runtime.
+  See issue: `#207 <https://github.com/ets-labs/python-dependency-injector/issues/207>`_.
+- Add attributes forwarding for the ``Dependency`` provider.
+
 4.24.0
 ------
 - Add docs on ``@containers.copy()`` decorator.

examples/miniapps/application-multiple-containers-runtime-overriding/README.rst

@@ -0,0 +1,17 @@
+Application example (multiple containers, runtime config overriding)
+====================================================================
+
+This example demonstrates how to build application from multiple containers
+and override one container config from another one in the runtime.
+
+Run:
+
+.. code-block:: bash
+
+   python -m example
+
+You should see:
+
+.. code-block:: bash
+
+   Adapter=[DB Path=[~/test]], queue=[Some storage]

examples/miniapps/application-multiple-containers-runtime-overriding/example/__init__.py

@@ -0,0 +1 @@
+"""Top-level package."""

examples/miniapps/application-multiple-containers-runtime-overriding/example/__main__.py

@@ -0,0 +1,12 @@
+"""Main module."""
+
+from .containers import Application
+
+
+if __name__ == '__main__':
+    application = Application()
+    config = application.service.config()
+    config.build()
+
+    print(application.repository.site())
+    # Output: Adapter=[DB Path=[~/test]], queue=[Some storage]

examples/miniapps/application-multiple-containers-runtime-overriding/example/containers.py

@@ -0,0 +1,45 @@
+"""Containers module."""
+
+from dependency_injector import containers, providers
+
+from .services import ConfigService
+
+
+class Core(containers.DeclarativeContainer):
+    config = providers.Configuration('config')
+
+
+class Storage(containers.DeclarativeContainer):
+    queue = providers.Singleton(lambda: 'Some storage')
+
+
+class Adapter(containers.DeclarativeContainer):
+    core = providers.DependenciesContainer(config=providers.Configuration())
+    tinydb = providers.Singleton(
+        lambda db_path: f'DB Path=[{db_path}]',
+        db_path=core.config.default.db_path,
+    )
+
+
+class Repository(containers.DeclarativeContainer):
+    adapter = providers.DependenciesContainer()
+    storage = providers.DependenciesContainer()
+    site = providers.Singleton(
+        lambda adapter, queue: f'Adapter=[{adapter}], queue=[{queue}]',
+        adapter=adapter.tinydb,
+        queue=storage.queue,
+    )
+
+
+class Service(containers.DeclarativeContainer):
+    core = providers.DependenciesContainer()
+    config = providers.Singleton(ConfigService, core.config.provider)
+
+
+class Application(containers.DeclarativeContainer):
+
+    core = providers.Container(Core)
+    storage = providers.Container(Storage)
+    adapter = providers.Container(Adapter, core=core)
+    repository = providers.Container(Repository, adapter=adapter, storage=storage)
+    service = providers.Container(Service, core=core)

examples/miniapps/application-multiple-containers-runtime-overriding/example/services.py

@@ -0,0 +1,9 @@
+"""Services module."""
+
+
+class ConfigService:
+    def __init__(self, config):
+        self._config = config
+
+    def build(self):
+        self._config.from_dict({'default': {'db_path': '~/test'}})