added warning log

Author: Victoria Hall

azure_functions_worker/functions.py

@@ -3,6 +3,7 @@
 import inspect
 import operator
 import pathlib
+import re
 import typing
 import uuid
 
@@ -11,6 +12,7 @@
 from ._thirdparty import typing_inspect
 from .constants import HTTP_TRIGGER
 from .protos import BindingInfo
+from .logging import logger
 
 
 class ParamTypeInfo(typing.NamedTuple):
@@ -130,6 +132,15 @@ def is_context_required(params, bound_params: dict,
                         f'{ctx_anno!r}')
         return requires_context
 
+    @staticmethod
+    def validate_arg_name(params: dict):
+        pattern = r'(^\d|\b\w*__\w*|\w{129,})'
+        for arg_name in params:
+            if re.search(pattern, arg_name):
+                logger.warning("Argument name %s is invalid. Please "
+                               "ensure it does not contain '__', start with a digit, "
+                               "or exceed 128 characters.", arg_name)
+
     @staticmethod
     def validate_function_params(params: dict, bound_params: dict,
                                  annotations: dict, func_name: str):
@@ -389,6 +400,8 @@ def add_function(self, function_id: str,
                                                     annotations,
                                                     func_name)
 
+        self.validate_arg_name(params)
+
         input_types, output_types, _ = self.validate_function_params(
             params, bound_params, annotations, func_name)
 

tests/unittests/broken_functions/double_underscore_arg_name/function.json

@@ -0,0 +1,15 @@
+{
+  "scriptFile": "main.py",
+  "bindings": [
+    {
+      "type": "httpTrigger",
+      "direction": "in",
+      "name": "__req"
+    },
+    {
+      "type": "http",
+      "direction": "out",
+      "name": "$return"
+    }
+  ]
+}

tests/unittests/broken_functions/double_underscore_arg_name/main.py

@@ -0,0 +1,8 @@
+# Copyright (c) Microsoft Corporation. All rights reserved.
+# Licensed under the MIT License.
+import azure.functions as azf
+
+
+def main(__req: azf.HttpRequest):
+    return azf.HttpResponse('<h1>Hello World™</h1>',
+                            mimetype='text/html')

tests/unittests/test_broken_functions.py

@@ -297,3 +297,24 @@ async def test_import_module_troubleshooting_url(self):
             self.assertRegex(
                 r.response.result.exception.message,
                 r'.*ModuleNotFoundError')
+
+    async def test_double_underscore_arg_name(self):
+        async with testutils.start_mockhost(
+                script_root=self.broken_funcs_dir) as host:
+            await host.init_worker()
+            func_id, r = await host.load_function('double_underscore_arg_name')
+
+            self.assertEqual(r.response.function_id, func_id)
+            # Indexing does not fail here
+            self.assertEqual(r.response.result.status,
+                             protos.StatusResult.Success)
+
+            message_present = False
+            warning_log = ("Argument name __req is invalid. "
+                           "Please ensure it does not contain "
+                           "\'__\', start with a digit, or exceed 128 characters.")
+            for log in r.logs:
+                if warning_log in log.message:
+                    message_present = True
+                    break
+            self.assertTrue(message_present)