Add async mode for the provider

src/dependency_injector/providers.pxd

@@ -14,6 +14,7 @@ cimport cython
 cdef class Provider(object):
     cdef tuple __overridden
     cdef Provider __last_overriding
+    cdef int __async_mode
 
     cpdef object _provide(self, tuple args, dict kwargs)
     cpdef void _copy_overridings(self, Provider copied, dict memo)

src/dependency_injector/providers.pyi

@@ -169,7 +169,7 @@ class Configuration(Object):
 class Factory(Provider, Generic[T]):
     provided_type: Optional[Type]
     def __init__(self, provides: _Callable[..., T], *args: Injection, **kwargs: Injection) -> None: ...
-    def __call__(self, *args: Injection, **kwargs: Injection) -> T: ...
+    def __call__(self, *args: Injection, **kwargs: Injection) -> Union[T, Awaitable[T]]: ...
     @property
     def cls(self) -> T: ...
     @property

src/dependency_injector/providers.pyx

@@ -89,6 +89,11 @@ else:
             return parser
 
 
+cdef int ASYNC_MODE_UNDEFINED = 0
+cdef int ASYNC_MODE_ENABLED = 1
+cdef int ASYNC_MODE_DISABLED = 2
+
+
 cdef class Provider(object):
     """Base provider class.
 
@@ -149,6 +154,7 @@ cdef class Provider(object):
         """Initializer."""
         self.__overridden = tuple()
         self.__last_overriding = None
+        self.__async_mode = ASYNC_MODE_UNDEFINED
         super(Provider, self).__init__()
 
     def __call__(self, *args, **kwargs):
@@ -157,8 +163,24 @@ cdef class Provider(object):
         Callable interface implementation.
         """
         if self.__last_overriding is not None:
-            return self.__last_overriding(*args, **kwargs)
-        return self._provide(args, kwargs)
+            result = self.__last_overriding(*args, **kwargs)
+        else:
+            result = self._provide(args, kwargs)
+
+        if self.__async_mode == ASYNC_MODE_DISABLED:
+            return result
+        elif self.__async_mode == ASYNC_MODE_ENABLED:
+            if not __isawaitable(result):
+                future_result = asyncio.Future()
+                future_result.set_result(result)
+                return future_result
+            return result
+        elif self.__async_mode == ASYNC_MODE_UNDEFINED:
+            if __isawaitable(result):
+                self.__async_mode = ASYNC_MODE_ENABLED
+            else:
+                self.__async_mode = ASYNC_MODE_DISABLED
+            return result
 
     def __deepcopy__(self, memo):
         """Create and return full copy of provider."""

tests/unit/providers/test_async_py36.py

@@ -511,3 +511,62 @@ class DependencyTests(AsyncTestCase):
         dependency4 = self._run(provider())
         self.assertEqual(dependency3, dependency)
         self.assertEqual(dependency4, dependency)
+
+
+class OverrideTests(AsyncTestCase):
+
+    def test_provider(self):
+        dependency = object()
+
+        async def _get_dependency_async():
+            return dependency
+
+        def _get_dependency_sync():
+            return dependency
+
+        provider = providers.Provider()
+
+        provider.override(providers.Callable(_get_dependency_async))
+        dependency1 = self._run(provider())
+
+        provider.override(providers.Callable(_get_dependency_sync))
+        dependency2 = self._run(provider())
+
+        self.assertIs(dependency1, dependency)
+        self.assertIs(dependency2, dependency)
+
+    def test_callable(self):
+        dependency = object()
+
+        async def _get_dependency_async():
+            return dependency
+
+        def _get_dependency_sync():
+            return dependency
+
+        provider = providers.Callable(_get_dependency_async)
+        dependency1 = self._run(provider())
+
+        provider.override(providers.Callable(_get_dependency_sync))
+        dependency2 = self._run(provider())
+
+        self.assertIs(dependency1, dependency)
+        self.assertIs(dependency2, dependency)
+
+    def test_factory(self):
+        dependency = object()
+
+        async def _get_dependency_async():
+            return dependency
+
+        def _get_dependency_sync():
+            return dependency
+
+        provider = providers.Factory(_get_dependency_async)
+        dependency1 = self._run(provider())
+
+        provider.override(providers.Callable(_get_dependency_sync))
+        dependency2 = self._run(provider())
+
+        self.assertIs(dependency1, dependency)
+        self.assertIs(dependency2, dependency)