178 dependencies container provider (#179)

* Add DependenciesContainer provider

* Remove bundles_v2 example

* Add use cases example

* Update changelog

* Update documentation requirements to use fixed version of sphinxcontrib-disqus

* Add use cases miniapp to docs

* Update changelog

docs/examples/index.rst

@@ -18,3 +18,4 @@ and powered by *Dependency Injector* framework.
     movie_lister
     services_miniapp
     bundles_miniapp
+    use_cases_miniapp

docs/examples/use_cases_miniapp.rst

@@ -0,0 +1,57 @@
+Use cases mini application example
+----------------------------------
+
+.. currentmodule:: dependency_injector.providers
+
+"Use cases" miniapp demonstrate usage of :py:class:`DependenciesContainer` 
+provider.
+
+Example application
+~~~~~~~~~~~~~~~~~~~
+
+"Use cases" mini application has next structure:
+
+.. code-block:: bash
+
+    use_cases/
+        example/               <-- Example package
+            __init__.py
+            adapters.py
+            use_cases.py
+        containers.py          <-- Dependency injection containers
+        run.py                 <-- Entrypoint
+
+
+IoC containers
+~~~~~~~~~~~~~~
+
+Listing of ``use_cases/containers.py``:
+
+.. literalinclude:: ../../examples/miniapps/use_cases/containers.py
+   :language: python
+   :linenos:
+
+Run application
+~~~~~~~~~~~~~~~
+
+Listing of ``run.py``:
+
+.. literalinclude:: ../../examples/miniapps/use_cases/run.py
+   :language: python
+   :linenos:
+
+Instructions for running:
+
+.. code-block:: bash
+
+    python run.py prod example@example.com  # Running in "production" environment
+    python run.py test example@example.com  # Running in "testing" environment
+
+Links
+~~~~~
+
++ `Dependency Injector <https://github.com/ets-labs/python-dependency-injector/>`_
++ `Full example sources <https://github.com/ets-labs/python-dependency-injector/tree/master/examples/miniapps/use_cases>`_
+
+
+.. disqus::

docs/main/changelog.rst

@@ -7,6 +7,15 @@ that were made in every particular version.
 From version 0.7.6 *Dependency Injector* framework strictly 
 follows `Semantic versioning`_
 
+
+3.10.0
+------
+- Add ``DependenciesContainer`` provider.
+- Add "use_cases" example miniapp.
+- Update documentation requirements to use fixed version of 
+  ``sphinxcontrib-disqus``.
+
+
 3.9.1
 -----
 - Fix docs build problem (``sphinx`` is frozen on ``1.5.6`` version because of

examples/miniapps/use_cases/README.rst

@@ -0,0 +1,9 @@
+Dependency Injector Use Cases example
+=====================================
+
+Instructions for running
+
+.. code-block:: bash
+
+    python run.py prod example@example.com  # Running in "production" environment
+    python run.py test example@example.com  # Running in "testing" environment

examples/miniapps/use_cases/containers.py

@@ -0,0 +1,30 @@
+"""Dependency injection containers for 'Use Cases' example application."""
+
+from dependency_injector import containers, providers
+
+from example.adapters import SmtpEmailSender, EchoEmailSender
+from example.use_cases import SignupUseCase
+
+
+class Adapters(containers.DeclarativeContainer):
+    """Adapters container."""
+
+    email_sender = providers.Singleton(SmtpEmailSender)
+
+
+class TestAdapters(containers.DeclarativeContainer):
+    """Adapters container.
+
+    This container is used for testing purposes.
+    """
+
+    email_sender = providers.Singleton(EchoEmailSender)
+
+
+class UseCases(containers.DeclarativeContainer):
+    """Use cases container."""
+
+    adapters = providers.DependenciesContainer()
+
+    signup = providers.Factory(SignupUseCase,
+                               email_sender=adapters.email_sender)

examples/miniapps/use_cases/example/__init__.py

@@ -0,0 +1 @@
+"""Example top-level package."""

examples/miniapps/use_cases/example/adapters.py

@@ -0,0 +1,25 @@
+"""Example adapters package."""
+
+
+class EmailSender(object):
+    """Abstract email sender."""
+
+    def send(self, to, body):
+        """Send email to specified email."""
+        raise NotImplementedError()
+
+
+class SmtpEmailSender(object):
+    """SMTP email sender uses SMTP protocol for sending emails."""
+
+    def send(self, to, body):
+        """Send email to specified email."""
+        # Send email via SMTP
+
+
+class EchoEmailSender(object):
+    """Echo email sender prints emails to stdout."""
+
+    def send(self, to, body):
+        """Send email to specified email."""
+        print('Sending email to "{0}", body = "{1}"'.format(to, body))

examples/miniapps/use_cases/example/use_cases.py

@@ -0,0 +1,22 @@
+"""Example use cases package."""
+
+
+class UseCase(object):
+    """Abstract use case."""
+
+    def execute(self):
+        """Execute use case handling."""
+        raise NotImplementedError()
+
+
+class SignupUseCase(object):
+    """Sign up use cases registers users."""
+
+    def __init__(self, email_sender):
+        """Initializer."""
+        self.email_sender = email_sender
+
+    def execute(self, email):
+        """Execute use case handling."""
+        print('Sign up user {0}'.format(email))
+        self.email_sender.send(email, 'Welcome, "{}"'.format(email))

examples/miniapps/use_cases/run.py

@@ -0,0 +1,19 @@
+"""Run 'Use Cases' example application."""
+
+import sys
+
+from containers import Adapters, TestAdapters, UseCases
+
+
+if __name__ == '__main__':
+    environment, email = sys.argv[1:]
+
+    if environment == 'prod':
+        adapters = Adapters()
+    elif environment == 'test':
+        adapters = TestAdapters()
+
+    use_cases = UseCases(adapters=adapters)
+
+    use_case = use_cases.signup()
+    use_case.execute(email)

requirements-doc.txt

@@ -1,5 +1,5 @@
-sphinx==1.5.6
+sphinx
-sphinx_rtd_theme>=0.2.5b1
+-e git://github.com/rmk135/sphinxcontrib-disqus.git#egg=sphinxcontrib-disqus
 sphinx_autobuild
 sphinxcontrib-disqus
 autodoc

src/dependency_injector/providers.pxd

@@ -13,6 +13,7 @@ cdef class Provider(object):
     cdef object __overriding_lock
 
     cpdef object _provide(self, tuple args, dict kwargs)
+    cpdef void _copy_overridings(self, Provider copied)
 
 
 cdef class Object(Provider):
@@ -33,6 +34,12 @@ cdef class ExternalDependency(Dependency):
     pass
 
 
+cdef class DependenciesContainer(Object):
+    cdef dict __providers
+
+    cpdef object _override_providers(self, object container)
+
+
 cdef class OverridingContext(object):
     cdef Provider __overridden
     cdef Provider __overriding

src/dependency_injector/providers.pyx

@@ -107,8 +107,7 @@ cdef class Provider(object):
 
         copied = self.__class__()
 
-        for overriding_provider in self.overridden:
+        self._copy_overridings(copied)
-            copied.override(deepcopy(overriding_provider, memo))
 
         return copied
 
@@ -215,6 +214,11 @@ cdef class Provider(object):
         """
         raise NotImplementedError()
 
+    cpdef void _copy_overridings(self, Provider copied):
+        """Copy provider overridings to a newly copied provider."""
+        copied.__overridden = deepcopy(self.__overridden)
+        copied.__last_overriding = deepcopy(self.__last_overriding)
+
 
 cdef class Object(Provider):
     """Object provider returns provided instance "as is".
@@ -243,8 +247,7 @@ cdef class Object(Provider):
 
         copied = self.__class__(deepcopy(self.__provides, memo))
 
-        for overriding_provider in self.overridden:
+        self._copy_overridings(copied)
-            copied.override(deepcopy(overriding_provider, memo))
 
         return copied
 
@@ -330,8 +333,7 @@ cdef class Dependency(Provider):
 
         copied = self.__class__(self.__instance_of)
 
-        for overriding_provider in self.overridden:
+        self._copy_overridings(copied)
-            copied.override(deepcopy(overriding_provider, memo))
 
         return copied
 
@@ -418,6 +420,121 @@ cdef class ExternalDependency(Dependency):
     """
 
 
+cdef class DependenciesContainer(Object):
+    """:py:class:`DependenciesContainer` provider provides set of dependencies.
+
+
+    Dependencies container provider is used to implement late static binding
+    for a set of providers of a particular container.
+
+
+    Example code:
+
+    .. code-block:: python
+
+        class Adapters(containers.DeclarativeContainer):
+            email_sender = providers.Singleton(SmtpEmailSender)
+
+        class TestAdapters(containers.DeclarativeContainer):
+            email_sender = providers.Singleton(EchoEmailSender)
+
+        class UseCases(containers.DeclarativeContainer):
+            adapters = providers.DependenciesContainer()
+
+            signup = providers.Factory(SignupUseCase,
+                                       email_sender=adapters.email_sender)
+
+        use_cases = UseCases(adapters=Adapters)
+        # or
+        use_cases = UseCases(adapters=TestAdapters)
+
+        # Another file
+        from .containers import use_cases
+
+        use_case = use_cases.signup()
+        use_case.execute()
+    """
+
+    def __init__(self, provides=None, **dependencies):
+        """Initializer."""
+        self.__providers = dependencies
+
+        if provides:
+            self._override_providers(container=provides)
+
+        super(DependenciesContainer, self).__init__(provides)
+
+    def __deepcopy__(self, memo):
+        """Create and return full copy of provider."""
+        cdef DependenciesContainer copied
+
+        copied = memo.get(id(self))
+        if copied is not None:
+            return copied
+
+        copied = self.__class__()
+        copied.__provides = deepcopy(self.__provides, memo)
+        copied.__providers = deepcopy(self.__providers, memo)
+
+        self._copy_overridings(copied)
+
+        return copied
+
+    def __getattr__(self, name):
+        """Return dependency provider."""
+        if name.startswith('__') and name.endswith('__'):
+            raise AttributeError(
+                '\'{cls}\' object has no attribute '
+                '\'{attribute_name}\''.format(cls=self.__class__.__name__,
+                                              attribute_name=name))
+
+        provider = self.__providers.get(name)
+        if not provider:
+            provider = Dependency()
+            self.__providers[name] = provider
+
+            container = self.__call__()
+            if container:
+                dependency_provider = container.providers.get(name)
+                if dependency_provider:
+                    provider.override(dependency_provider)
+
+        return provider
+
+    @property
+    def providers(self):
+        """Read-only dictionary of dependency providers."""
+        return self.__providers
+
+    def override(self, provider):
+        """Override provider with another provider.
+
+        :param provider: Overriding provider.
+        :type provider: :py:class:`Provider`
+
+        :raise: :py:exc:`dependency_injector.errors.Error`
+
+        :return: Overriding context.
+        :rtype: :py:class:`OverridingContext`
+        """
+        self._override_providers(container=provider)
+        return super(DependenciesContainer, self).override(provider)
+
+
+    cpdef object _override_providers(self, object container):
+        """Override providers with providers from provided container."""
+        for name, dependency_provider in container.providers.items():
+            provider = self.__providers.get(name)
+
+            if not provider:
+                continue
+
+            if provider.last_overriding is dependency_provider:
+                continue
+
+            provider.override(dependency_provider)
+
+
 cdef class OverridingContext(object):
     """Provider overriding context.
 
@@ -517,8 +634,7 @@ cdef class Callable(Provider):
                                 *deepcopy(self.args, memo),
                                 **deepcopy(self.kwargs, memo))
 
-        for overriding_provider in self.overridden:
+        self._copy_overridings(copied)
-            copied.override(deepcopy(overriding_provider, memo))
 
         return copied
 
@@ -755,8 +871,7 @@ cdef class Configuration(Provider):
         copied.__value = deepcopy(self.__value, memo)
         copied.__children = deepcopy(self.__children, memo)
 
-        for overriding_provider in self.overridden:
+        self._copy_overridings(copied)
-            copied.override(deepcopy(overriding_provider, memo))
 
         return copied
 
@@ -923,8 +1038,7 @@ cdef class Factory(Provider):
                                 **deepcopy(self.kwargs, memo))
         copied.set_attributes(**deepcopy(self.attributes, memo))
 
-        for overriding_provider in self.overridden:
+        self._copy_overridings(copied)
-            copied.override(deepcopy(overriding_provider, memo))
 
         return copied
 
@@ -1272,8 +1386,7 @@ cdef class BaseSingleton(Provider):
                                 **deepcopy(self.kwargs, memo))
         copied.set_attributes(**deepcopy(self.attributes, memo))
 
-        for overriding_provider in self.overridden:
+        self._copy_overridings(copied)
-            copied.override(deepcopy(overriding_provider, memo))
 
         return copied
 

tests/unit/providers/test_base.py

@@ -3,6 +3,7 @@
 import unittest2 as unittest
 
 from dependency_injector import (
+    containers,
     providers,
     errors,
 )
@@ -298,3 +299,52 @@ class ExternalDependencyTests(unittest.TestCase):
 
     def test_is_instance(self):
         self.assertIsInstance(self.provider, providers.Dependency)
+
+
+class DependenciesContainerTests(unittest.TestCase):
+
+    class Container(containers.DeclarativeContainer):
+
+        dependency = providers.Provider()
+
+    def setUp(self):
+        self.provider = providers.DependenciesContainer()
+        self.container = self.Container()
+
+    def test_getattr(self):
+        has_dependency = hasattr(self.provider, 'dependency')
+        dependency = self.provider.dependency
+
+        self.assertIsInstance(dependency, providers.Dependency)
+        self.assertIs(dependency, self.provider.dependency)
+        self.assertTrue(has_dependency)
+        self.assertIsNone(dependency.last_overriding)
+
+    def test_getattr_with_container(self):
+        self.provider.override(self.container)
+
+        dependency = self.provider.dependency
+
+        self.assertTrue(dependency.overridden)
+        self.assertIs(dependency.last_overriding, self.container.dependency)
+
+    def test_providers(self):
+        dependency1 = self.provider.dependency1
+        dependency2 = self.provider.dependency2
+        self.assertEqual(self.provider.providers, {'dependency1': dependency1,
+                                                   'dependency2': dependency2})
+
+    def test_override(self):
+        dependency = self.provider.dependency
+        self.provider.override(self.container)
+
+        self.assertTrue(dependency.overridden)
+        self.assertIs(dependency.last_overriding, self.container.dependency)
+
+    def test_init_with_container_and_providers(self):
+        provider = providers.DependenciesContainer(
+            self.container, dependency=providers.Dependency())
+        dependency = provider.dependency
+
+        self.assertTrue(dependency.overridden)
+        self.assertIs(dependency.last_overriding, self.container.dependency)