Add Configuration.from_json() method (#602)

* Add implementation and tests

* Refactor naming in configuration fixtures

* Add typing for .from_json()

* Move get/set_ini_files() methods upper

* Add init implementation and tests

* Refactor typing tests

* Add examples

* Add docs

* Update docs index and readme

* Update changelog

Author: rmk135

README.rst

@@ -59,7 +59,7 @@ Key features of the ``Dependency Injector``:
 - **Overriding**. Can override any provider by another provider on the fly. This helps in testing
   and configuring dev/stage environment to replace API clients with stubs etc. See
   `Provider overriding <https://python-dependency-injector.ets-labs.org/providers/overriding.html>`_.
-- **Configuration**. Reads configuration from ``yaml`` & ``ini`` files, ``pydantic`` settings,
+- **Configuration**. Reads configuration from ``yaml``, ``ini``, and ``json`` files, ``pydantic`` settings,
   environment variables, and dictionaries.
   See `Configuration provider <https://python-dependency-injector.ets-labs.org/providers/configuration.html>`_.
 - **Resources**. Helps with initialization and configuring of logging, event loop, thread

docs/index.rst

@@ -70,7 +70,7 @@ Key features of the ``Dependency Injector``:
 - **Overriding**. Can override any provider by another provider on the fly. This helps in testing
   and configuring dev/stage environment to replace API clients with stubs etc. See
   :ref:`provider-overriding`.
-- **Configuration**. Reads configuration from ``yaml`` & ``ini`` files, ``pydantic`` settings,
+- **Configuration**. Reads configuration from ``yaml``, ``ini``, and ``json`` files, ``pydantic`` settings,
   environment variables, and dictionaries. See :ref:`configuration-provider`.
 - **Resources**. Helps with initialization and configuring of logging, event loop, thread
   or process pool, etc. Can be used for per-function execution scope in tandem with wiring.

docs/introduction/key_features.rst

@@ -16,7 +16,7 @@ Key features of the ``Dependency Injector``:
 - **Overriding**. Can override any provider by another provider on the fly. This helps in testing
   and configuring dev/stage environment to replace API clients with stubs etc. See
   :ref:`provider-overriding`.
-- **Configuration**. Reads configuration from ``yaml`` & ``ini`` files, ``pydantic`` settings,
+- **Configuration**. Reads configuration from ``yaml``, ``ini``, and ``json`` files, ``pydantic`` settings,
   environment variables, and dictionaries. See :ref:`configuration-provider`.
 - **Resources**. Helps with initialization and configuring of logging, event loop, thread
   or process pool, etc. Can be used for per-function execution scope in tandem with wiring.

docs/main/changelog.rst

@@ -10,6 +10,7 @@ follows `Semantic versioning`_
 
 Development
 -----------
+- Add ``Configuration.from_json()`` method to load configuration from a json file.
 - Improve wording on the "Dependency injection and inversion of control in Python" docs page.
 - Update typing in the main example and cohesion/coupling correlation definition in
   "Dependency injection and inversion of control in Python".

docs/providers/configuration.rst

@@ -136,6 +136,50 @@ To use another loader use ``loader`` argument:
 
    *Don't forget to mirror the changes in the requirements file.*
 
+Loading from a JSON file
+------------------------
+
+``Configuration`` provider can load configuration from a ``json`` file using the
+:py:meth:`Configuration.from_json` method:
+
+.. literalinclude:: ../../examples/providers/configuration/configuration_json.py
+   :language: python
+   :lines: 3-
+   :emphasize-lines: 12
+
+where ``examples/providers/configuration/config.json`` is:
+
+.. literalinclude:: ../../examples/providers/configuration/config.json
+   :language: json
+
+Alternatively, you can provide a path to a json file over the configuration provider argument. In that case,
+the container will call ``config.from_json()`` automatically:
+
+.. code-block:: python
+   :emphasize-lines: 3
+
+   class Container(containers.DeclarativeContainer):
+
+       config = providers.Configuration(json_files=["./config.json"])
+
+
+   if __name__ == "__main__":
+       container = Container()  # Config is loaded from ./config.json
+
+:py:meth:`Configuration.from_json` method supports environment variables interpolation.
+
+.. code-block:: json
+
+   {
+       "section": {
+           "option1": "${ENV_VAR}",
+           "option2": "${ENV_VAR}/path",
+           "option3": "${ENV_VAR:default}"
+       }
+   }
+
+See also: :ref:`configuration-envs-interpolation`.
+
 Loading from a Pydantic settings
 --------------------------------
 

examples/providers/configuration/config.json

@@ -0,0 +1,6 @@
+{
+    "aws": {
+        "access_key_id": "KEY",
+        "secret_access_key": "SECRET"
+    }
+}

examples/providers/configuration/configuration_json.py

@@ -0,0 +1,27 @@
+"""`Configuration` provider values loading example."""
+
+from dependency_injector import containers, providers
+
+
+class Container(containers.DeclarativeContainer):
+
+    config = providers.Configuration()
+
+
+if __name__ == "__main__":
+    container = Container()
+
+    container.config.from_json("./config.json")
+
+    assert container.config() == {
+        "aws": {
+            "access_key_id": "KEY",
+            "secret_access_key": "SECRET",
+        },
+    }
+    assert container.config.aws() == {
+        "access_key_id": "KEY",
+        "secret_access_key": "SECRET",
+    }
+    assert container.config.aws.access_key_id() == "KEY"
+    assert container.config.aws.secret_access_key() == "SECRET"

examples/providers/configuration/configuration_json_init.py

@@ -0,0 +1,25 @@
+"""`Configuration` provider values loading example."""
+
+from dependency_injector import containers, providers
+
+
+class Container(containers.DeclarativeContainer):
+
+    config = providers.Configuration(json_files=["./config.json"])
+
+
+if __name__ == "__main__":
+    container = Container()
+
+    assert container.config() == {
+        "aws": {
+            "access_key_id": "KEY",
+            "secret_access_key": "SECRET",
+        },
+    }
+    assert container.config.aws() == {
+        "access_key_id": "KEY",
+        "secret_access_key": "SECRET",
+    }
+    assert container.config.aws.access_key_id() == "KEY"
+    assert container.config.aws.secret_access_key() == "SECRET"