Add a default script_file for function.json without scriptFile (#893)

Author: vrdmr

azure_functions_worker/loader.py

@@ -11,13 +11,14 @@
 import pathlib
 import sys
 import typing
+from os import PathLike, fspath
 
 from .constants import MODULE_NOT_FOUND_TS_URL
 from .utils.wrappers import attach_message_to_exception
-from os import PathLike, fspath
-
 
 _AZURE_NAMESPACE = '__app__'
+_DEFAULT_SCRIPT_FILENAME = '__init__.py'
+_DEFAULT_ENTRY_POINT = 'main'
 
 _submodule_dirs = []
 
@@ -50,9 +51,10 @@ def uninstall() -> None:
 def load_function(name: str, directory: str, script_file: str,
                   entry_point: typing.Optional[str]):
     dir_path = pathlib.Path(directory)
-    script_path = pathlib.Path(script_file)
+    script_path = pathlib.Path(script_file) if script_file else pathlib.Path(
+        _DEFAULT_SCRIPT_FILENAME)
     if not entry_point:
-        entry_point = 'main'
+        entry_point = _DEFAULT_ENTRY_POINT
 
     register_function_dir(dir_path.parent)
 

tests/unittests/load_functions/no_script_file/function.json

@@ -0,0 +1,14 @@
+{
+  "bindings": [
+    {
+      "type": "httpTrigger",
+      "direction": "in",
+      "name": "req"
+    },
+    {
+      "type": "http",
+      "direction": "out",
+      "name": "$return"
+    }
+  ]
+}

tests/unittests/load_functions/no_script_file/main.py

@@ -0,0 +1,6 @@
+# Copyright (c) Microsoft Corporation. All rights reserved.
+# Licensed under the MIT License.
+
+
+def main(req) -> str:
+    return __name__

tests/unittests/test_loader.py

@@ -25,6 +25,11 @@ def test_loader_custom_entrypoint(self):
         self.assertEqual(r.status_code, 200)
         self.assertEqual(r.text, '__app__.entrypoint.main')
 
+    def test_loader_no_script_file(self):
+        r = self.webhost.request('GET', 'no_script_file')
+        self.assertEqual(r.status_code, 200)
+        self.assertEqual(r.text, '__app__.no_script_file.main')
+
     def test_loader_subdir(self):
         r = self.webhost.request('GET', 'subdir')
         self.assertEqual(r.status_code, 200)