Fix bug #361: failure on async resource depends on other async resource

docs/main/changelog.rst

@@ -7,6 +7,13 @@ that were made in every particular version.
 From version 0.7.6 *Dependency Injector* framework strictly 
 follows `Semantic versioning`_
 
+Development version
+-------------------
+- Fix a bug in ``Resource`` that cause failure when async resource depends on
+  another async resource.
+  See issue `#361 <https://github.com/ets-labs/python-dependency-injector/issues/361>`_.
+  Thanks `@kolypto <https://github.com/kolypto>`_ for the bug report.
+
 4.10.1
 ------
 - Fix a Python 3.9 specific bug in ``wiring`` module: introspection doesn't work for

src/dependency_injector/providers.pyx

@@ -2967,7 +2967,7 @@ cdef class Resource(Provider):
                 self.__kwargs_len,
             )
             self.__initialized = True
-            return self._create_init_future(initializer.__anext__(), initializer.asend)
+            return self._create_async_gen_init_future(initializer)
         elif callable(self.__initializer):
             self.__resource = __call(
                 self.__initializer,
@@ -2995,6 +2995,18 @@ cdef class Resource(Provider):
 
         return future
 
+    def _create_async_gen_init_future(self, initializer):
+        if inspect.isasyncgen(initializer):
+            return self._create_init_future(initializer.__anext__(), initializer.asend)
+
+        future = asyncio.Future()
+
+        create_initializer = asyncio.ensure_future(initializer)
+        create_initializer.add_done_callback(functools.partial(self._async_create_gen_callback, future))
+        self.__resource = future
+
+        return future
+
     def _async_init_callback(self, initializer, shutdowner=None):
         try:
             resource = initializer.result()
@@ -3005,6 +3017,14 @@ cdef class Resource(Provider):
             self.__resource = resource
             self.__shutdowner = shutdowner
 
+    def _async_create_gen_callback(self, future, initializer_future):
+        initializer = initializer_future.result()
+        init_future = self._create_init_future(initializer.__anext__(), initializer.asend)
+        init_future.add_done_callback(functools.partial(self._async_trigger_result, future))
+
+    def _async_trigger_result(self, future, future_result):
+        future.set_result(future_result.result())
+
     def _create_shutdown_future(self, shutdown_future):
         future = asyncio.Future()
         shutdown_future = asyncio.ensure_future(shutdown_future)

tests/unit/providers/test_resource_py35.py

@@ -461,6 +461,43 @@ class AsyncResourceTest(AsyncTestCase):
         self.assertFalse(provider.initialized)
         self.assertTrue(provider.is_async_mode_enabled())
 
+    def test_init_with_dependency_to_other_resource(self):
+        # See: https://github.com/ets-labs/python-dependency-injector/issues/361
+        async def init_db_connection(db_url: str):
+            await asyncio.sleep(0.001)
+            yield {'connection': 'ok', 'url': db_url}
+
+        async def init_user_session(db):
+            await asyncio.sleep(0.001)
+            yield {'session': 'ok', 'db': db}
+
+        class Container(containers.DeclarativeContainer):
+            config = providers.Configuration()
+
+            db_connection = providers.Resource(
+                init_db_connection,
+                db_url=config.db_url,
+            )
+
+            user_session = providers.Resource(
+                init_user_session,
+                db=db_connection
+            )
+
+        async def main():
+            container = Container(config={'db_url': 'postgres://...'})
+            try:
+                return await container.user_session()
+            finally:
+                await container.shutdown_resources()
+
+        result = self._run(main())
+
+        self.assertEqual(
+            result,
+            {'session': 'ok', 'db': {'connection': 'ok', 'url': 'postgres://...'}},
+        )
+
     def test_init_and_shutdown_methods(self):
         async def _init():
             await asyncio.sleep(0.001)