Async handle adaptor (#143)

* Add AnatoliB to CodeOwners

* Create an async handler and deprecate the old

* DeprecationWarning is a builtin

* fix flake8 violations

Co-authored-by: Hanzhang Zeng <48038149+Hazhzeng@users.noreply.github.com>
Co-authored-by: AzureFunctionsPython <funcdisc@microsoft.com>
Co-authored-by: Varad <varad.meru@gmail.com>

Author: 4 people

azure/functions/_http_asgi.py

@@ -4,6 +4,7 @@
 from typing import Dict, List, Tuple, Optional, Any, Union
 import logging
 import asyncio
+from warnings import warn
 from wsgiref.headers import Headers
 
 from ._abc import Context
@@ -149,18 +150,20 @@ def __init__(self, app):
         self.main = self._handle
 
     def handle(self, req: HttpRequest, context: Optional[Context] = None):
-        """Method to convert an Azure Functions HTTP request into a ASGI
-        Python object. Example on handling ASGI app in a HTTP trigger by
-        calling .handle() in .main() method:
+        """Deprecated. Please use handle_async instead:
 
         import azure.functions as func
 
         from FastapiApp import app
 
-        def main(req, context):
-            return func.AsgiMiddleware(app).handle(req, context)
+        async def main(req, context):
+            return await func.AsgiMiddleware(app).handle_async(req, context)
         """
+        warn("handle() is deprecated. Please use handle_async() instead.",
+             DeprecationWarning, stacklevel=2)
         self._logger.debug(f"Handling {req.url} as an ASGI request.")
+        self._logger.warning(
+            "handle() is deprecated. Please `await .handle_async()` instead.")
         return self._handle(req, context)
 
     def _handle(self, req, context):
@@ -172,3 +175,29 @@ def _handle(self, req, context):
         )
 
         return asgi_response.to_func_response()
+
+    async def handle_async(self,
+                           req: HttpRequest,
+                           context: Optional[Context] = None):
+        """Method to convert an Azure Functions HTTP request into a ASGI
+        Python object. Example on handling ASGI app in a HTTP trigger by
+        calling .handle_async() in .main() method:
+
+            import azure.functions as func
+
+            from FastapiApp import app
+
+            async def main(req, context):
+                return await func.AsgiMiddleware(app).handle_async(req,
+                                                                   context)
+        """
+        self._logger.debug(f"Awaiting {req.url} as an ASGI request.")
+        return await self._handle_async(req, context)
+
+    async def _handle_async(self, req, context):
+        asgi_request = AsgiRequest(req, context)
+        scope = asgi_request.to_asgi_http_scope()
+        asgi_response = await AsgiResponse.from_app(self._app,
+                                                    scope,
+                                                    req.get_body())
+        return asgi_response.to_func_response()

tests/test_http_asgi.py

@@ -1,6 +1,7 @@
 # Copyright (c) Microsoft Corporation. All rights reserved.
 # Licensed under the MIT License.
 
+import asyncio
 import unittest
 
 import azure.functions as func
@@ -194,3 +195,22 @@ def test_middleware_wrapper(self):
         # Verify asserted
         self.assertEqual(response.status_code, 200)
         self.assertEqual(response.get_body(), test_body)
+
+    def test_middleware_async_calls_app_with_context(self):
+        """Test the middleware with the awaitable handle_async() method
+        async def main(req, context):
+            return await AsgiMiddleware(app).handle_async(req, context)
+        """
+        app = MockAsgiApplication()
+        test_body = b'Hello world!'
+        app.response_body = test_body
+        app.response_code = 200
+        req = self._generate_func_request()
+        ctx = self._generate_func_context()
+        response = asyncio.get_event_loop().run_until_complete(
+            AsgiMiddleware(app).handle_async(req, ctx)
+        )
+
+        # Verify asserted
+        self.assertEqual(response.status_code, 200)
+        self.assertEqual(response.get_body(), test_body)