Move importing azfunc to init request

azure_functions_worker/constants.py

@@ -30,6 +30,9 @@
 """
 UNIX_SHARED_MEMORY_DIRECTORIES = "FUNCTIONS_UNIX_SHARED_MEMORY_DIRECTORIES"
 
+# Flag to enable loading functions at init request
+PYTHON_LOAD_FUNCTIONS_INIT = "PYTHON_LOAD_FUNCTIONS_INIT"
+
 # Setting Defaults
 PYTHON_THREADPOOL_THREAD_COUNT_DEFAULT = 1
 PYTHON_THREADPOOL_THREAD_COUNT_MIN = 1

azure_functions_worker/dispatcher.py

@@ -26,7 +26,7 @@
                         PYTHON_THREADPOOL_THREAD_COUNT_MAX_37,
                         PYTHON_THREADPOOL_THREAD_COUNT_MIN,
                         PYTHON_ENABLE_DEBUG_LOGGING, SCRIPT_FILE_NAME,
-                        PYTHON_LANGUAGE_RUNTIME)
+                        PYTHON_LANGUAGE_RUNTIME, PYTHON_LOAD_FUNCTIONS_INIT)
 from .extension import ExtensionManager
 from .logging import disable_console_logging, enable_console_logging
 from .logging import enable_debug_logging_recommendation
@@ -288,6 +288,10 @@ async def _handle__worker_init_request(self, request):
         if not DependencyManager.is_in_linux_consumption():
             DependencyManager.prioritize_customer_dependencies()
 
+        if DependencyManager.is_in_linux_consumption() \
+                and is_envvar_true(PYTHON_LOAD_FUNCTIONS_INIT):
+            import azure.functions  # NoQA
+
         return protos.StreamingMessage(
             request_id=self.request_id,
             worker_init_response=protos.WorkerInitResponse(
@@ -525,10 +529,11 @@ async def _handle__function_environment_reload_request(self, request):
             func_env_reload_request = \
                 request.function_environment_reload_request
 
-            # Import before clearing path cache so that the default
-            # azure.functions modules is available in sys.modules for
-            # customer use
-            import azure.functions  # NoQA
+            if not is_envvar_true(PYTHON_LOAD_FUNCTIONS_INIT):
+                # Import before clearing path cache so that the default
+                # azure.functions modules is available in sys.modules for
+                # customer use
+                import azure.functions  # NoQA
 
             # Append function project root to module finding sys.path
             if func_env_reload_request.function_app_directory:

tests/unittests/test_dispatcher.py

@@ -599,3 +599,36 @@ async def test_dispatcher_functions_metadata_request_legacy_fallback(self):
             self.assertTrue(r.response.use_default_metadata_indexing)
             self.assertEqual(r.response.result.status,
                              protos.StatusResult.Success)
+
+
+class TestDispatcherLoadFunctionInInitRequest(testutils.AsyncTestCase):
+
+    def setUp(self):
+        self._ctrl = testutils.start_mockhost(
+            script_root=DISPATCHER_FUNCTIONS_DIR)
+        self._pre_env = dict(os.environ)
+        self.mock_version_info = patch(
+            'azure_functions_worker.dispatcher.sys.version_info',
+            SysVersionInfo(3, 9, 0, 'final', 0))
+        self.mock_version_info.start()
+
+    def tearDown(self):
+        os.environ.clear()
+        os.environ.update(self._pre_env)
+        self.mock_version_info.stop()
+
+    async def test_dispatcher_load_azfunc_in_init(self):
+        """Test if the dispatcher's log can be flushed out during worker
+        initialization
+        """
+        os.environ.update({"CONTAINER_NAME": 'test',
+                           "PYTHON_LOAD_FUNCTIONS_INIT": "1"})
+        async with self._ctrl as host:
+            r = await host.init_worker('4.15.1')
+            self.assertEqual(
+                len([log for log in r.logs if log.message.startswith(
+                    'Received WorkerInitRequest'
+                )]),
+                1
+            )
+        self.assertIn("azure.functions", sys.modules)