Reduce INFO logging (#8050)

c.f. #8021 

A lot of the code here is to change the `Completed 200 OK` logging to include the request URI so that we can drop the `Sending request...` log line.

Some notes:

1. We won't log retries, which may be confusing considering the time taken log line includes retries and sleeps.
2. The `_send_request_with_optional_trailing_slash` will always be logged *without* the forward slash, even if it succeeded only with the forward slash.

4 files changed, 74 insertions, 25 deletions

diff --git a/changelog.d/8050.misc b/changelog.d/8050.misc
new file mode 100644
index 0000000000..cc8d1af7fa
--- /dev/null
+++ b/changelog.d/8050.misc
@@ -0,0 +1 @@
+Reduce amount of outbound request logging at INFO level.
diff --git a/synapse/http/client.py b/synapse/http/client.py
index 529532a063..8aeb70cdec 100644
--- a/synapse/http/client.py
+++ b/synapse/http/client.py
@@ -297,7 +297,7 @@ class SimpleHttpClient(object):
         outgoing_requests_counter.labels(method).inc()
 
         # log request but strip `access_token` (AS requests for example include this)
-        logger.info("Sending request %s %s", method, redact_uri(uri))
+        logger.debug("Sending request %s %s", method, redact_uri(uri))
 
         with start_active_span(
             "outgoing-client-request",
diff --git a/synapse/http/federation/matrix_federation_agent.py b/synapse/http/federation/matrix_federation_agent.py
index 0c02648015..369bf9c2fc 100644
--- a/synapse/http/federation/matrix_federation_agent.py
+++ b/synapse/http/federation/matrix_federation_agent.py
@@ -247,7 +247,7 @@ class MatrixHostnameEndpoint(object):
             port = server.port
 
             try:
-                logger.info("Connecting to %s:%i", host.decode("ascii"), port)
+                logger.debug("Connecting to %s:%i", host.decode("ascii"), port)
                 endpoint = HostnameEndpoint(self._reactor, host, port)
                 if self._tls_options:
                     endpoint = wrapClientTLS(self._tls_options, endpoint)
diff --git a/synapse/http/matrixfederationclient.py b/synapse/http/matrixfederationclient.py
index 2a6373937a..738be43f46 100644
--- a/synapse/http/matrixfederationclient.py
+++ b/synapse/http/matrixfederationclient.py
@@ -29,10 +29,11 @@ from zope.interface import implementer
 
 from twisted.internet import defer, protocol
 from twisted.internet.error import DNSLookupError
-from twisted.internet.interfaces import IReactorPluggableNameResolver
+from twisted.internet.interfaces import IReactorPluggableNameResolver, IReactorTime
 from twisted.internet.task import _EPSILON, Cooperator
 from twisted.web._newclient import ResponseDone
 from twisted.web.http_headers import Headers
+from twisted.web.iweb import IResponse
 
 import synapse.metrics
 import synapse.util.retryutils
@@ -74,7 +75,7 @@ MAXINT = sys.maxsize
 _next_id = 1
 
 
-@attr.s
+@attr.s(frozen=True)
 class MatrixFederationRequest(object):
     method = attr.ib()
     """HTTP method
@@ -110,26 +111,52 @@ class MatrixFederationRequest(object):
     :type: str|None
     """
 
+    uri = attr.ib(init=False, type=bytes)
+    """The URI of this request
+    """
+
     def __attrs_post_init__(self):
         global _next_id
-        self.txn_id = "%s-O-%s" % (self.method, _next_id)
+        txn_id = "%s-O-%s" % (self.method, _next_id)
         _next_id = (_next_id + 1) % (MAXINT - 1)
 
+        object.__setattr__(self, "txn_id", txn_id)
+
+        destination_bytes = self.destination.encode("ascii")
+        path_bytes = self.path.encode("ascii")
+        if self.query:
+            query_bytes = encode_query_args(self.query)
+        else:
+            query_bytes = b""
+
+        # The object is frozen so we can pre-compute this.
+        uri = urllib.parse.urlunparse(
+            (b"matrix", destination_bytes, path_bytes, None, query_bytes, b"")
+        )
+        object.__setattr__(self, "uri", uri)
+
     def get_json(self):
         if self.json_callback:
             return self.json_callback()
         return self.json
 
 
-async def _handle_json_response(reactor, timeout_sec, request, response):
+async def _handle_json_response(
+    reactor: IReactorTime,
+    timeout_sec: float,
+    request: MatrixFederationRequest,
+    response: IResponse,
+    start_ms: int,
+):
     """
     Reads the JSON body of a response, with a timeout
 
     Args:
-        reactor (IReactor): twisted reactor, for the timeout
-        timeout_sec (float): number of seconds to wait for response to complete
-        request (MatrixFederationRequest): the request that triggered the response
-        response (IResponse): response to the request
+        reactor: twisted reactor, for the timeout
+        timeout_sec: number of seconds to wait for response to complete
+        request: the request that triggered the response
+        response: response to the request
+        start_ms: Timestamp when request was made
 
     Returns:
         dict: parsed JSON response
@@ -143,23 +170,35 @@ async def _handle_json_response(reactor, timeout_sec, request, response):
         body = await make_deferred_yieldable(d)
     except TimeoutError as e:
         logger.warning(
-            "{%s} [%s] Timed out reading response", request.txn_id, request.destination,
+            "{%s} [%s] Timed out reading response - %s %s",
+            request.txn_id,
+            request.destination,
+            request.method,
+            request.uri.decode("ascii"),
         )
         raise RequestSendFailed(e, can_retry=True) from e
     except Exception as e:
         logger.warning(
-            "{%s} [%s] Error reading response: %s",
+            "{%s} [%s] Error reading response %s %s: %s",
             request.txn_id,
             request.destination,
+            request.method,
+            request.uri.decode("ascii"),
             e,
         )
         raise
+
+    time_taken_secs = reactor.seconds() - start_ms / 1000
+
     logger.info(
-        "{%s} [%s] Completed: %d %s",
+        "{%s} [%s] Completed request: %d %s in %.2f secs - %s %s",
         request.txn_id,
         request.destination,
         response.code,
         response.phrase.decode("ascii", errors="replace"),
+        time_taken_secs,
+        request.method,
+        request.uri.decode("ascii"),
     )
     return body
 
@@ -261,7 +300,9 @@ class MatrixFederationHttpClient(object):
             # 'M_UNRECOGNIZED' which some endpoints can return when omitting a
             # trailing slash on Synapse <= v0.99.3.
             logger.info("Retrying request with trailing slash")
-            request.path += "/"
+
+            # Request is frozen so we create a new instance
+            request = attr.evolve(request, path=request.path + "/")
 
             response = await self._send_request(request, **send_request_args)
 
@@ -373,9 +414,7 @@ class MatrixFederationHttpClient(object):
             else:
                 retries_left = MAX_SHORT_RETRIES
 
-            url_bytes = urllib.parse.urlunparse(
-                (b"matrix", destination_bytes, path_bytes, None, query_bytes, b"")
-            )
+            url_bytes = request.uri
             url_str = url_bytes.decode("ascii")
 
             url_to_sign_bytes = urllib.parse.urlunparse(
@@ -402,7 +441,7 @@ class MatrixFederationHttpClient(object):
 
                     headers_dict[b"Authorization"] = auth_headers
 
-                    logger.info(
+                    logger.debug(
                         "{%s} [%s] Sending request: %s %s; timeout %fs",
                         request.txn_id,
                         request.destination,
@@ -436,7 +475,6 @@ class MatrixFederationHttpClient(object):
                     except DNSLookupError as e:
                         raise RequestSendFailed(e, can_retry=retry_on_dns_fail) from e
                     except Exception as e:
-                        logger.info("Failed to send request: %s", e)
                         raise RequestSendFailed(e, can_retry=True) from e
 
                     incoming_responses_counter.labels(
@@ -496,7 +534,7 @@ class MatrixFederationHttpClient(object):
 
                     break
                 except RequestSendFailed as e:
-                    logger.warning(
+                    logger.info(
                         "{%s} [%s] Request failed: %s %s: %s",
                         request.txn_id,
                         request.destination,
@@ -654,6 +692,8 @@ class MatrixFederationHttpClient(object):
             json=data,
         )
 
+        start_ms = self.clock.time_msec()
+
         response = await self._send_request_with_optional_trailing_slash(
             request,
             try_trailing_slash_on_400,
@@ -664,7 +704,7 @@ class MatrixFederationHttpClient(object):
         )
 
         body = await _handle_json_response(
-            self.reactor, self.default_timeout, request, response
+            self.reactor, self.default_timeout, request, response, start_ms
         )
 
         return body
@@ -720,6 +760,8 @@ class MatrixFederationHttpClient(object):
             method="POST", destination=destination, path=path, query=args, json=data
         )
 
+        start_ms = self.clock.time_msec()
+
         response = await self._send_request(
             request,
             long_retries=long_retries,
@@ -733,7 +775,7 @@ class MatrixFederationHttpClient(object):
             _sec_timeout = self.default_timeout
 
         body = await _handle_json_response(
-            self.reactor, _sec_timeout, request, response
+            self.reactor, _sec_timeout, request, response, start_ms,
         )
         return body
 
@@ -786,6 +828,8 @@ class MatrixFederationHttpClient(object):
             method="GET", destination=destination, path=path, query=args
         )
 
+        start_ms = self.clock.time_msec()
+
         response = await self._send_request_with_optional_trailing_slash(
             request,
             try_trailing_slash_on_400,
@@ -796,7 +840,7 @@ class MatrixFederationHttpClient(object):
         )
 
         body = await _handle_json_response(
-            self.reactor, self.default_timeout, request, response
+            self.reactor, self.default_timeout, request, response, start_ms
         )
 
         return body
@@ -846,6 +890,8 @@ class MatrixFederationHttpClient(object):
             method="DELETE", destination=destination, path=path, query=args
         )
 
+        start_ms = self.clock.time_msec()
+
         response = await self._send_request(
             request,
             long_retries=long_retries,
@@ -854,7 +900,7 @@ class MatrixFederationHttpClient(object):
         )
 
         body = await _handle_json_response(
-            self.reactor, self.default_timeout, request, response
+            self.reactor, self.default_timeout, request, response, start_ms
         )
         return body
 
@@ -914,12 +960,14 @@ class MatrixFederationHttpClient(object):
             )
             raise
         logger.info(
-            "{%s} [%s] Completed: %d %s [%d bytes]",
+            "{%s} [%s] Completed: %d %s [%d bytes] %s %s",
             request.txn_id,
             request.destination,
             response.code,
             response.phrase.decode("ascii", errors="replace"),
             length,
+            request.method,
+            request.uri.decode("ascii"),
         )
         return (length, headers)