update decoupled-example with abstraction layer

docs/examples/decoupled-packages.rst

@@ -55,6 +55,17 @@ file.
 
    ./
    ├── example/
+   │   ├── abstraction
+   │   │   ├── __init__.py
+   │   │   ├── analytics
+   │   │   │   ├── __init__.py
+   │   │   │   └── services.py
+   │   │   ├── photo
+   │   │   │   ├── __init__.py
+   │   │   │   └── repositories.py
+   │   │   └── user
+   │   │       ├── __init__.py
+   │   │       └── repositories.py
    │   ├── analytics/
    │   │   ├── __init__.py
    │   │   ├── containers.py
@@ -75,6 +86,26 @@ file.
    ├── config.ini
    └── requirements.txt
 
+
+Abstraction
+------------------
+
+Listing of the ``example/abstraction/user/repositories.py``:
+
+.. literalinclude:: ../../examples/miniapps/decoupled-packages/example/abstraction/user/repositories.py
+   :language: python
+
+Listing of the ``example/abstraction/photo/repositories.py``:
+
+.. literalinclude:: ../../examples/miniapps/decoupled-packages/example/abstraction/photo/repositories.py
+   :language: python
+
+Listing of the ``example/abstraction/analytics/services.py``:
+
+.. literalinclude:: ../../examples/miniapps/decoupled-packages/example/abstraction/analytics/services.py
+   :language: python
+
+
 Package containers
 ------------------
 

examples/miniapps/decoupled-packages/example/__main__.py

@@ -2,21 +2,22 @@
 
 from dependency_injector.wiring import Provide, inject
 
-from .user.repositories import UserRepository
-from .photo.repositories import PhotoRepository
-from .analytics.services import AggregationService
+from .abstraction.user.repositories import UserRepositoryMeta
+from .abstraction.photo.repositories import PhotoRepositoryMeta
+from .abstraction.analytics.services import AggregationServiceMeta
+
 from .containers import ApplicationContainer
 
 
 @inject
 def main(
-        user_repository: UserRepository = Provide[
+        user_repository: UserRepositoryMeta = Provide[
             ApplicationContainer.user_package.user_repository
         ],
-        photo_repository: PhotoRepository = Provide[
+        photo_repository: PhotoRepositoryMeta = Provide[
             ApplicationContainer.photo_package.photo_repository
         ],
-        aggregation_service: AggregationService = Provide[
+        aggregation_service: AggregationServiceMeta = Provide[
             ApplicationContainer.analytics_package.aggregation_service
         ],
 ) -> None:
@@ -32,6 +33,8 @@ def main(
     assert aggregation_service.photo_repository is photo_repository
     print("Aggregate analytics from user and photo packages")
 
+    aggregation_service.call_user_photo()
+
 
 if __name__ == "__main__":
     application = ApplicationContainer()

examples/miniapps/decoupled-packages/example/abstraction/__init__.py

@@ -0,0 +1 @@
+"""abstraction package."""

examples/miniapps/decoupled-packages/example/abstraction/analytics/__init__.py

@@ -0,0 +1 @@
+"""abstraction analytics package."""

examples/miniapps/decoupled-packages/example/abstraction/analytics/services.py

@@ -0,0 +1,19 @@
+"""Analytics services module."""
+
+import abc
+
+
+from ..photo.repositories import PhotoRepositoryMeta
+from ..user.repositories import UserRepositoryMeta
+
+
+class AggregationServiceMeta(metaclass=abc.ABCMeta):
+
+    def __init__(self, user_repository: UserRepositoryMeta, photo_repository: PhotoRepositoryMeta):
+        self.user_repository: UserRepositoryMeta = user_repository
+        self.photo_repository: PhotoRepositoryMeta = photo_repository
+
+    @abc.abstractmethod
+    def call_user_photo(self):
+        """Must be implemented in order to instantiate."""
+        pass

examples/miniapps/decoupled-packages/example/abstraction/photo/__init__.py

@@ -0,0 +1 @@
+"""abstraction photo package."""

examples/miniapps/decoupled-packages/example/abstraction/photo/repositories.py

@@ -0,0 +1,11 @@
+"""Photo repositories Meta module."""
+
+import abc
+
+
+class PhotoRepositoryMeta(metaclass=abc.ABCMeta):
+
+    @abc.abstractmethod
+    def get_photos(self, user_id):
+        """Must be implemented in order to instantiate."""
+        pass

examples/miniapps/decoupled-packages/example/abstraction/user/__init__.py

@@ -0,0 +1 @@
+"""abstraction user package."""

examples/miniapps/decoupled-packages/example/abstraction/user/repositories.py

@@ -0,0 +1,12 @@
+"""User repositories meta module."""
+
+
+import abc
+
+
+class UserRepositoryMeta(metaclass=abc.ABCMeta):
+
+    @abc.abstractmethod
+    def get(self, id):
+        """Must be implemented in order to instantiate."""
+        pass

examples/miniapps/decoupled-packages/example/analytics/containers.py

@@ -4,11 +4,14 @@
 
 from . import services
 
+from ..abstraction.photo.repositories import PhotoRepositoryMeta
+from ..abstraction.user.repositories import UserRepositoryMeta
+
 
 class AnalyticsContainer(containers.DeclarativeContainer):
 
-    user_repository = providers.Dependency()
-    photo_repository = providers.Dependency()
+    user_repository: UserRepositoryMeta = providers.Dependency()
+    photo_repository: PhotoRepositoryMeta = providers.Dependency()
 
     aggregation_service = providers.Singleton(
         services.AggregationService,

examples/miniapps/decoupled-packages/example/analytics/services.py

@@ -1,8 +1,18 @@
 """Analytics services module."""
 
 
-class AggregationService:
+from ..abstraction.analytics.services import AggregationServiceMeta
+from ..abstraction.photo.repositories import PhotoRepositoryMeta
+from ..abstraction.user.repositories import UserRepositoryMeta
 
-    def __init__(self, user_repository, photo_repository):
-        self.user_repository = user_repository
-        self.photo_repository = photo_repository
+
+class AggregationService(AggregationServiceMeta):
+
+    def __init__(self, user_repository: UserRepositoryMeta, photo_repository: PhotoRepositoryMeta):
+        self.user_repository: UserRepositoryMeta = user_repository
+        self.photo_repository: PhotoRepositoryMeta = photo_repository
+
+    def call_user_photo(self):
+        user1 = self.user_repository.get(id=1)
+        user1_photos = self.photo_repository.get_photos(user1.id)
+        print(f"Retrieve user id={user1.id}, photos count={len(user1_photos)} from aggregation service.")

examples/miniapps/decoupled-packages/example/photo/repositories.py

@@ -1,7 +1,10 @@
 """Photo repositories module."""
 
 
-class PhotoRepository:
+from ..abstraction.photo.repositories import PhotoRepositoryMeta
+
+
+class PhotoRepository(PhotoRepositoryMeta):
 
     def __init__(self, entity_factory, fs, db):
         self.entity_factory = entity_factory

examples/miniapps/decoupled-packages/example/user/repositories.py

@@ -1,7 +1,9 @@
 """User repositories module."""
 
+from ..abstraction.user.repositories import UserRepositoryMeta
 
-class UserRepository:
+
+class UserRepository(UserRepositoryMeta):
 
     def __init__(self, entity_factory, db):
         self.entity_factory = entity_factory