Configurable file name

azure_functions_worker/constants.py

@@ -30,6 +30,7 @@
 data transfer between host and worker.
 """
 UNIX_SHARED_MEMORY_DIRECTORIES = "FUNCTIONS_UNIX_SHARED_MEMORY_DIRECTORIES"
+SCRIPT_FILE_NAME = "SCRIPT_FILE_NAME"
 
 # Setting Defaults
 PYTHON_THREADPOOL_THREAD_COUNT_DEFAULT = 1
@@ -43,11 +44,12 @@
 PYTHON_ENABLE_WORKER_EXTENSIONS_DEFAULT_39 = True
 PYTHON_EXTENSIONS_RELOAD_FUNCTIONS = "PYTHON_EXTENSIONS_RELOAD_FUNCTIONS"
 
+# new programming model default script file name
+SCRIPT_FILE_NAME_DEFAULT = "function_app.py"
+
 # External Site URLs
 MODULE_NOT_FOUND_TS_URL = "https://aka.ms/functions-modulenotfound"
 
-# new programming model script file name
-SCRIPT_FILE_NAME = "function_app.py"
 PYTHON_LANGUAGE_RUNTIME = "python"
 
 # Settings for V2 programming model

azure_functions_worker/dispatcher.py

@@ -26,6 +26,7 @@
                         PYTHON_THREADPOOL_THREAD_COUNT_MAX_37,
                         PYTHON_THREADPOOL_THREAD_COUNT_MIN,
                         PYTHON_ENABLE_DEBUG_LOGGING, SCRIPT_FILE_NAME,
+                        SCRIPT_FILE_NAME_DEFAULT,
                         PYTHON_LANGUAGE_RUNTIME, CUSTOMER_PACKAGES_PATH)
 from .extension import ExtensionManager
 from .logging import disable_console_logging, enable_console_logging
@@ -324,7 +325,10 @@ async def _handle__worker_status_request(self, request):
     async def _handle__functions_metadata_request(self, request):
         metadata_request = request.functions_metadata_request
         directory = metadata_request.function_app_directory
-        function_path = os.path.join(directory, SCRIPT_FILE_NAME)
+        script_file_name = get_app_setting(
+            setting=SCRIPT_FILE_NAME,
+            default_value=SCRIPT_FILE_NAME_DEFAULT)
+        function_path = os.path.join(directory, script_file_name)
 
         logger.info(
             'Received WorkerMetadataRequest, request ID %s, directory: %s',
@@ -333,7 +337,7 @@ async def _handle__functions_metadata_request(self, request):
         if not os.path.exists(function_path):
             # Fallback to legacy model
             logger.info("%s does not exist. "
-                        "Switching to host indexing.", SCRIPT_FILE_NAME)
+                        "Switching to host indexing.", script_file_name)
             return protos.StreamingMessage(
                 request_id=request.request_id,
                 function_metadata_response=protos.FunctionMetadataResponse(
@@ -364,8 +368,13 @@ async def _handle__function_load_request(self, request):
         function_id = func_request.function_id
         function_metadata = func_request.metadata
         function_name = function_metadata.name
+
+        script_file_name = get_app_setting(
+            setting=SCRIPT_FILE_NAME,
+            default_value=SCRIPT_FILE_NAME_DEFAULT)
+
         function_path = os.path.join(function_metadata.directory,
-                                     SCRIPT_FILE_NAME)
+                                     script_file_name)
 
         logger.info(
             'Received WorkerLoadRequest, request ID %s, function_id: %s,'

azure_functions_worker/loader.py

@@ -17,8 +17,10 @@
 
 from . import protos, functions
 from .bindings.retrycontext import RetryPolicy
+from .utils.common import get_app_setting
 from .constants import MODULE_NOT_FOUND_TS_URL, SCRIPT_FILE_NAME, \
-    PYTHON_LANGUAGE_RUNTIME, RETRY_POLICY, CUSTOMER_PACKAGES_PATH
+    SCRIPT_FILE_NAME_DEFAULT, PYTHON_LANGUAGE_RUNTIME, \
+    CUSTOMER_PACKAGES_PATH, RETRY_POLICY
 from .logging import logger
 from .utils.wrappers import attach_message_to_exception
 
@@ -225,7 +227,9 @@ def index_function_app(function_path: str):
                     f"level function app instances are defined.")
 
     if not app:
+        script_file_name = get_app_setting(setting=SCRIPT_FILE_NAME,
+                                           default=SCRIPT_FILE_NAME_DEFAULT)
         raise ValueError("Could not find top level function app instances in "
-                         f"{SCRIPT_FILE_NAME}.")
+                         f"{script_file_name}.")
 
     return app.get_functions()

tests/unittests/test_dispatcher.py

@@ -12,7 +12,9 @@
 from tests.utils import testutils
 from azure_functions_worker.constants import PYTHON_THREADPOOL_THREAD_COUNT, \
     PYTHON_THREADPOOL_THREAD_COUNT_DEFAULT, \
-    PYTHON_THREADPOOL_THREAD_COUNT_MAX_37, PYTHON_THREADPOOL_THREAD_COUNT_MIN
+    PYTHON_THREADPOOL_THREAD_COUNT_MAX_37, \
+    PYTHON_THREADPOOL_THREAD_COUNT_MIN,  \
+    SCRIPT_FILE_NAME, SCRIPT_FILE_NAME_DEFAULT
 
 SysVersionInfo = col.namedtuple("VersionInfo", ["major", "minor", "micro",
                                                 "releaselevel", "serial"])
@@ -618,3 +620,41 @@ async def test_dispatcher_load_azfunc_in_init(self):
                 1
             )
         self.assertIn("azure.functions", sys.modules)
+
+
+class TestConfigurableFileName(testutils.AsyncTestCase):
+
+    def setUp(self):
+        self._ctrl = testutils.start_mockhost(
+            script_root=DISPATCHER_FUNCTIONS_DIR)
+        self._default_file_name: Optional[str] = SCRIPT_FILE_NAME_DEFAULT
+        self._new_file_name: str = 'test.py'
+        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_default_file_name(self):
+        """
+        Test the default file name
+        """
+        os.environ.update({SCRIPT_FILE_NAME: self._default_file_name})
+        self.assertIsNotNone(os.environ.get(SCRIPT_FILE_NAME))
+        self.assertEqual(os.environ.get(SCRIPT_FILE_NAME),
+                         self._default_file_name)
+
+    # test changing value
+    async def test_dispatcher_new_file_name(self):
+        """
+        Test the updated file name
+        """
+        os.environ.update({SCRIPT_FILE_NAME: self._new_file_name})
+        self.assertIsNotNone(os.environ.get(SCRIPT_FILE_NAME))
+        self.assertEqual(os.environ.get(SCRIPT_FILE_NAME),
+                         self._new_file_name)