Add web_application_options setting to configure the web application (#551)

faust/types/settings/settings.py

@@ -158,6 +158,7 @@ def __init__(
         canonical_url: URLArg = None,
         web: URLArg = None,
         web_bind: Optional[str] = None,
+        web_application_options: typing.Mapping[str, typing.Any] = None,
         web_cors_options: typing.Mapping[str, ResourceOptions] = None,
         web_enabled: Optional[bool] = None,
         web_host: Optional[str] = None,
@@ -1857,6 +1858,34 @@ def web_bind(self) -> str:
         not by passing it as a keyword argument to :class:`app`.
         """
 
+    @sections.WebServer.setting(
+        params.Dict[Any],
+        version_introduced="0.11.4",
+    )
+    def web_application_options(self) -> Mapping[str, Any]:
+        """Extra keyword arguments passed to the web framework's application.
+
+        Use this to configure the underlying web application object that the
+        web driver creates.  For the default :pypi:`aiohttp` driver these are
+        forwarded straight to :class:`aiohttp.web.Application`, so you can set
+        things like ``client_max_size`` or install middlewares:
+
+        .. sourcecode:: python
+
+            from aiohttp.web import middleware
+
+            @middleware
+            async def error_middleware(request, handler):
+                ...
+
+            app = App(..., web_application_options={
+                'client_max_size': 1024 ** 2 * 20,
+                'middlewares': [error_middleware],
+            })
+
+        The accepted keys depend on the configured web driver.
+        """
+
     @sections.WebServer.setting(
         params.Dict[ResourceOptions],
         version_introduced="1.5",

faust/web/drivers/aiohttp.py

@@ -89,7 +89,9 @@ class Web(base.Web):
 
     def __init__(self, app: AppT, **kwargs: Any) -> None:
         super().__init__(app, **kwargs)
-        self.web_app: Application = Application()
+        self.web_app: Application = Application(
+            **(app.conf.web_application_options or {})
+        )
         self.cors_options = _prepare_cors_options(app.conf.web_cors_options or {})
         self._runner: AppRunner = AppRunner(self.web_app, access_log=None)
         self._transport_handlers = {

tests/functional/test_app.py

@@ -552,6 +552,7 @@ def test_defaults(self):
         assert conf.web_bind == "0.0.0.0"
         assert conf.web_port == 6066
         assert conf.web_transport == Settings.web_transport.default
+        assert conf.web_application_options is None
         assert conf.web_cors_options is None
         assert conf.worker_redirect_stdouts
         assert conf.worker_redirect_stdouts_level == "WARN"
@@ -666,6 +667,7 @@ def assert_config_equivalent(
         web_host="localhost",
         web_transport="udp://",
         web_in_thread=True,
+        web_application_options={"client_max_size": 1024},  # noqa: B006
         web_cors_options={  # noqa: B006
             "http://example.com": ResourceOptions(  # noqa: B008
                 allow_credentials=True,
@@ -742,6 +744,7 @@ def assert_config_equivalent(
             web_host=web_host,
             web_transport=web_transport,
             web_in_thread=web_in_thread,
+            web_application_options=web_application_options,
             web_cors_options=web_cors_options,
             worker_redirect_stdouts=worker_redirect_stdouts,
             worker_redirect_stdouts_level=worker_redirect_stdouts_level,
@@ -806,6 +809,7 @@ def assert_config_equivalent(
         assert conf.web_port == web_port
         assert conf.web_host == web_host
         assert conf.web_transport == URL(web_transport)
+        assert conf.web_application_options == web_application_options
         assert conf.web_cors_options == web_cors_options
         assert conf.worker_redirect_stdouts == worker_redirect_stdouts
         assert conf.worker_redirect_stdouts_level == worker_redirect_stdouts_level

tests/unit/web/drivers/test_aiohttp.py

@@ -14,6 +14,7 @@
     NON_OPTIONS_METHODS,
     Server,
     ServerThread,
+    Web,
     _prepare_cors_options,
 )
 from tests.helpers import AsyncMock
@@ -127,6 +128,25 @@ async def test_on_stop(self, *, server, web):
 
 
 class Test_Web:
+    @pytest.mark.conf(web_application_options={"client_max_size": 1234})
+    def test_web_application_options(self, *, app):
+        # web_application_options are forwarded to aiohttp.web.Application.
+        # See issue #551.
+        with (
+            patch("faust.web.drivers.aiohttp.Application") as Application,
+            patch("faust.web.drivers.aiohttp.AppRunner"),
+        ):
+            Web(app)
+            Application.assert_called_once_with(client_max_size=1234)
+
+    def test_web_application_options__default(self, *, app):
+        with (
+            patch("faust.web.drivers.aiohttp.Application") as Application,
+            patch("faust.web.drivers.aiohttp.AppRunner"),
+        ):
+            Web(app)
+            Application.assert_called_once_with()
+
     def test_cors(self, *, web):
         assert web.cors is web.cors
         assert isinstance(web.cors, aiohttp_cors.CorsConfig)