Client signals get rid of trace_request_ctx as signal kw (#2560)

* Client signals get rid of trace_request_ctx as signal kw

* Fix typo in documentation

* Renamed trace_config_ctx_class to trace_config_ctx_factory

aiohttp/client.py

@@ -226,9 +226,11 @@ async def _request(self, method, url, *,
 
         traces = [
             Trace(
-                trace_config,
                 self,
-                trace_request_ctx=trace_request_ctx)
+                trace_config,
+                trace_config.trace_config_ctx(
+                    trace_request_ctx=trace_request_ctx)
+            )
             for trace_config in self._trace_configs
         ]
 

aiohttp/tracing.py

@@ -10,7 +10,7 @@ class TraceConfig:
     """First-class used to trace requests launched via ClientSession
     objects."""
 
-    def __init__(self, trace_config_ctx_class=SimpleNamespace):
+    def __init__(self, trace_config_ctx_factory=SimpleNamespace):
         self._on_request_start = Signal(self)
         self._on_request_end = Signal(self)
         self._on_request_exception = Signal(self)
@@ -25,11 +25,12 @@ def __init__(self, trace_config_ctx_class=SimpleNamespace):
         self._on_dns_cache_hit = Signal(self)
         self._on_dns_cache_miss = Signal(self)
 
-        self._trace_config_ctx_class = trace_config_ctx_class
+        self._trace_config_ctx_factory = trace_config_ctx_factory
 
-    def trace_config_ctx(self):
+    def trace_config_ctx(self, trace_request_ctx=None):
         """ Return a new trace_config_ctx instance """
-        return self._trace_config_ctx_class()
+        return self._trace_config_ctx_factory(
+            trace_request_ctx=trace_request_ctx)
 
     def freeze(self):
         self._on_request_start.freeze()
@@ -103,18 +104,16 @@ class Trace:
     """ Internal class used to keep together the main dependencies used
     at the moment of send a signal."""
 
-    def __init__(self, trace_config, session, trace_request_ctx=None):
+    def __init__(self, session, trace_config, trace_config_ctx):
         self._trace_config = trace_config
-        self._trace_config_ctx = self._trace_config.trace_config_ctx()
-        self._trace_request_ctx = trace_request_ctx
+        self._trace_config_ctx = trace_config_ctx
         self._session = session
 
     async def send_request_start(self, *args, **kwargs):
         return await self._trace_config.on_request_start.send(
             self._session,
             self._trace_config_ctx,
             *args,
-            trace_request_ctx=self._trace_request_ctx,
             **kwargs
         )
 
@@ -123,7 +122,6 @@ async def send_request_end(self, *args, **kwargs):
             self._session,
             self._trace_config_ctx,
             *args,
-            trace_request_ctx=self._trace_request_ctx,
             **kwargs
         )
 
@@ -132,7 +130,6 @@ async def send_request_exception(self, *args, **kwargs):
             self._session,
             self._trace_config_ctx,
             *args,
-            trace_request_ctx=self._trace_request_ctx,
             **kwargs
         )
 
@@ -141,7 +138,6 @@ async def send_request_redirect(self, *args, **kwargs):
             self._session,
             self._trace_config_ctx,
             *args,
-            trace_request_ctx=self._trace_request_ctx,
             **kwargs
         )
 
@@ -150,7 +146,6 @@ async def send_connection_queued_start(self, *args, **kwargs):
             self._session,
             self._trace_config_ctx,
             *args,
-            trace_request_ctx=self._trace_request_ctx,
             **kwargs
         )
 
@@ -159,7 +154,6 @@ async def send_connection_queued_end(self, *args, **kwargs):
             self._session,
             self._trace_config_ctx,
             *args,
-            trace_request_ctx=self._trace_request_ctx,
             **kwargs
         )
 
@@ -168,7 +162,6 @@ async def send_connection_create_start(self, *args, **kwargs):
             self._session,
             self._trace_config_ctx,
             *args,
-            trace_request_ctx=self._trace_request_ctx,
             **kwargs
         )
 
@@ -177,7 +170,6 @@ async def send_connection_create_end(self, *args, **kwargs):
             self._session,
             self._trace_config_ctx,
             *args,
-            trace_request_ctx=self._trace_request_ctx,
             **kwargs
         )
 
@@ -186,7 +178,6 @@ async def send_connection_reuseconn(self, *args, **kwargs):
             self._session,
             self._trace_config_ctx,
             *args,
-            trace_request_ctx=self._trace_request_ctx,
             **kwargs
         )
 
@@ -195,7 +186,6 @@ async def send_dns_resolvehost_start(self, *args, **kwargs):
             self._session,
             self._trace_config_ctx,
             *args,
-            trace_request_ctx=self._trace_request_ctx,
             **kwargs
         )
 
@@ -204,7 +194,6 @@ async def send_dns_resolvehost_end(self, *args, **kwargs):
             self._session,
             self._trace_config_ctx,
             *args,
-            trace_request_ctx=self._trace_request_ctx,
             **kwargs
         )
 
@@ -213,7 +202,6 @@ async def send_dns_cache_hit(self, *args, **kwargs):
             self._session,
             self._trace_config_ctx,
             *args,
-            trace_request_ctx=self._trace_request_ctx,
             **kwargs
         )
 
@@ -222,6 +210,5 @@ async def send_dns_cache_miss(self, *args, **kwargs):
             self._session,
             self._trace_config_ctx,
             *args,
-            trace_request_ctx=self._trace_request_ctx,
             **kwargs
         )

docs/client_advanced.rst

@@ -217,12 +217,10 @@ disabled. The following snippet shows how the start and the end
 signals of a request flow can be followed::
 
     async def on_request_start(
-            session, trace_config_ctx, method,
-            host, port, headers, request_trace_config_ctx=None):
+            session, trace_config_ctx, method, host, port, headers):
         print("Starting request")
 
-    async def on_request_end(session, trace_config_ctx, resp,
-                             request_trace_config_ctx=None):
+    async def on_request_end(session, trace_config_ctx, resp):
         print("Ending request")
 
     trace_config = aiohttp.TraceConfig()
@@ -253,25 +251,30 @@ share the state through to the different signals that belong to the
 same request and to the same :class:`TraceConfig` class, perhaps::
 
     async def on_request_start(
-            session, trace_config_ctx, method, host, port, headers,
-            trace_request_ctx=None):
+            session, trace_config_ctx, method, host, port, headers):
         trace_config_ctx.start = session.loop.time()
 
-    async def on_request_end(
-            session, trace_config_ctx, resp, trace_request_ctx=None):
+    async def on_request_end(session, trace_config_ctx, resp):
         elapsed = session.loop.time() - trace_config_ctx.start
         print("Request took {}".format(elapsed))
 
 
 The ``trace_config_ctx`` param is by default a
 :class:`SimpleNampespace` that is initialized at the beginning of the
 request flow. However, the factory used to create this object can be
-overwritten using the ``trace_config_ctx_class`` constructor param of
+overwritten using the ``trace_config_ctx_factory`` constructor param of
 the :class:`TraceConfig` class.
 
 The ``trace_request_ctx`` param can given at the beginning of the
-request execution and will be passed as a keyword argument for all of
-the signals, as the following snippet shows::
+request execution, accepted by all of the HTTP verbs,  and will be
+passed as a keyword argument for the ``trace_config_ctx_factory``
+factory. This param is useful to pass data that is only available at
+request time, perhaps::
+
+    async def on_request_start(
+            session, trace_config_ctx, method, host, port, headers):
+        print(trace_config_ctx.trace_request_ctx)
+
 
     session.get('http://example.com/some/redirect/',
                 trace_request_ctx={'foo': 'bar'})

docs/client_reference.rst

@@ -294,9 +294,9 @@ The client session supports the context manager protocol for self closing.
 
          .. versionadded:: 2.3
 
-      :param trace_request_ctx: Object used to give as a kw param for the all
-        signals triggered by the ongoing request and for all :class:`TraceConfig`
-        configured. Default passes a None value.
+      :param trace_request_ctx: Object used to give as a kw param for each new
+        :class:`TraceConfig` object instantiated, used to give information to the
+        tracers that is only available at request time.
 
          .. versionadded:: 3.0
 

docs/tracing_reference.rst

@@ -14,12 +14,15 @@ Trace config is the configuration object used to trace requests launched by
 a Client session object using different events related to different parts of
 the request flow.
 
-.. class:: TraceConfig(trace_config_ctx_class=SimpleNamespace)
+.. class:: TraceConfig(trace_config_ctx_factory=SimpleNamespace)
 
-   :param trace_config_ctx_class: factory used to create trace contexts,
+   :param trace_config_ctx_factory: factory used to create trace contexts,
       default class used :class:`SimpleNamespace`
 
-   .. method:: trace_config_ctx()
+   .. method:: trace_config_ctx(trace_request_ctx=None)
+
+      :param trace_request_ctx: Will be used to pass as a kw for the
+        ``trace_config_ctx_factory``.
 
       Return a new trace context.
 

tests/test_client_session.py

@@ -462,7 +462,7 @@ async def test_request_tracing(loop):
     on_request_end = mock.Mock(side_effect=asyncio.coroutine(mock.Mock()))
 
     trace_config = aiohttp.TraceConfig(
-        trace_config_ctx_class=mock.Mock(return_value=trace_config_ctx)
+        trace_config_ctx_factory=mock.Mock(return_value=trace_config_ctx)
     )
     trace_config.on_request_start.append(on_request_start)
     trace_config.on_request_end.append(on_request_end)
@@ -480,8 +480,7 @@ async def test_request_tracing(loop):
         trace_config_ctx,
         hdrs.METH_GET,
         URL("http://example.com"),
-        CIMultiDict(),
-        trace_request_ctx=trace_request_ctx
+        CIMultiDict()
     )
 
     on_request_end.assert_called_once_with(
@@ -490,8 +489,7 @@ async def test_request_tracing(loop):
         hdrs.METH_GET,
         URL("http://example.com"),
         CIMultiDict(),
-        resp,
-        trace_request_ctx=trace_request_ctx
+        resp
     )
     assert not on_request_redirect.called
 
@@ -528,8 +526,7 @@ async def test_request_tracing_exception(loop):
             hdrs.METH_GET,
             URL("http://example.com"),
             CIMultiDict(),
-            error,
-            trace_request_ctx=mock.ANY
+            error
         )
         assert not on_request_end.called