Various clean-ups to the logging context code (#8935)

11 files changed, 20 insertions, 39 deletions

diff --git a/changelog.d/8916.misc b/changelog.d/8916.misc
index c71ef480e6..bf94135fd5 100644
--- a/changelog.d/8916.misc
+++ b/changelog.d/8916.misc
@@ -1 +1 @@
-Improve structured logging tests.
+Various clean-ups to the structured logging and logging context code.
diff --git a/changelog.d/8935.misc b/changelog.d/8935.misc
new file mode 100644
index 0000000000..bf94135fd5
--- /dev/null
+++ b/changelog.d/8935.misc
@@ -0,0 +1 @@
+Various clean-ups to the structured logging and logging context code.
diff --git a/synapse/config/logger.py b/synapse/config/logger.py
index d4e887a3e0..4df3f93c1c 100644
--- a/synapse/config/logger.py
+++ b/synapse/config/logger.py
@@ -206,7 +206,7 @@ def _setup_stdlib_logging(config, log_config_path, logBeginner: LogBeginner) ->
     # filter options, but care must when using e.g. MemoryHandler to buffer
     # writes.
 
-    log_context_filter = LoggingContextFilter(request="")
+    log_context_filter = LoggingContextFilter()
     log_metadata_filter = MetadataFilter({"server_name": config.server_name})
     old_factory = logging.getLogRecordFactory()
 
diff --git a/synapse/http/site.py b/synapse/http/site.py
index 5f0581dc3f..5a5790831b 100644
--- a/synapse/http/site.py
+++ b/synapse/http/site.py
@@ -128,8 +128,7 @@ class SynapseRequest(Request):
 
         # create a LogContext for this request
         request_id = self.get_request_id()
-        logcontext = self.logcontext = LoggingContext(request_id)
-        logcontext.request = request_id
+        self.logcontext = LoggingContext(request_id, request=request_id)
 
         # override the Server header which is set by twisted
         self.setHeader("Server", self.site.server_version_string)
diff --git a/synapse/logging/context.py b/synapse/logging/context.py
index ca0c774cc5..a507a83e93 100644
--- a/synapse/logging/context.py
+++ b/synapse/logging/context.py
@@ -203,10 +203,6 @@ class _Sentinel:
     def copy_to(self, record):
         pass
 
-    def copy_to_twisted_log_entry(self, record):
-        record["request"] = None
-        record["scope"] = None
-
     def start(self, rusage: "Optional[resource._RUsage]"):
         pass
 
@@ -372,13 +368,6 @@ class LoggingContext:
         # we also track the current scope:
         record.scope = self.scope
 
-    def copy_to_twisted_log_entry(self, record) -> None:
-        """
-        Copy logging fields from this context to a Twisted log record.
-        """
-        record["request"] = self.request
-        record["scope"] = self.scope
-
     def start(self, rusage: "Optional[resource._RUsage]") -> None:
         """
         Record that this logcontext is currently running.
@@ -542,13 +531,10 @@ class LoggingContext:
 class LoggingContextFilter(logging.Filter):
     """Logging filter that adds values from the current logging context to each
     record.
-    Args:
-        **defaults: Default values to avoid formatters complaining about
-            missing fields
     """
 
-    def __init__(self, **defaults) -> None:
-        self.defaults = defaults
+    def __init__(self, request: str = ""):
+        self._default_request = request
 
     def filter(self, record) -> Literal[True]:
         """Add each fields from the logging contexts to the record.
@@ -556,14 +542,14 @@ class LoggingContextFilter(logging.Filter):
             True to include the record in the log output.
         """
         context = current_context()
-        for key, value in self.defaults.items():
-            setattr(record, key, value)
+        record.request = self._default_request
 
         # context should never be None, but if it somehow ends up being, then
         # we end up in a death spiral of infinite loops, so let's check, for
         # robustness' sake.
         if context is not None:
-            context.copy_to(record)
+            # Logging is interested in the request.
+            record.request = context.request
 
         return True
 
diff --git a/synapse/metrics/background_process_metrics.py b/synapse/metrics/background_process_metrics.py
index 76b7decf26..70e0fa45d9 100644
--- a/synapse/metrics/background_process_metrics.py
+++ b/synapse/metrics/background_process_metrics.py
@@ -199,8 +199,7 @@ def run_as_background_process(desc: str, func, *args, bg_start_span=True, **kwar
         _background_process_start_count.labels(desc).inc()
         _background_process_in_flight_count.labels(desc).inc()
 
-        with BackgroundProcessLoggingContext(desc) as context:
-            context.request = "%s-%i" % (desc, count)
+        with BackgroundProcessLoggingContext(desc, "%s-%i" % (desc, count)) as context:
             try:
                 ctx = noop_context_manager()
                 if bg_start_span:
@@ -244,8 +243,8 @@ class BackgroundProcessLoggingContext(LoggingContext):
 
     __slots__ = ["_proc"]
 
-    def __init__(self, name: str):
-        super().__init__(name)
+    def __init__(self, name: str, request: Optional[str] = None):
+        super().__init__(name, request=request)
 
         self._proc = _BackgroundProcess(name, self)
 
diff --git a/synapse/replication/tcp/protocol.py b/synapse/replication/tcp/protocol.py
index a509e599c2..804da994ea 100644
--- a/synapse/replication/tcp/protocol.py
+++ b/synapse/replication/tcp/protocol.py
@@ -172,8 +172,7 @@ class BaseReplicationStreamProtocol(LineOnlyReceiver):
         # a logcontext which we use for processing incoming commands. We declare it as a
         # background process so that the CPU stats get reported to prometheus.
         ctx_name = "replication-conn-%s" % self.conn_id
-        self._logging_context = BackgroundProcessLoggingContext(ctx_name)
-        self._logging_context.request = ctx_name
+        self._logging_context = BackgroundProcessLoggingContext(ctx_name, ctx_name)
 
     def connectionMade(self):
         logger.info("[%s] Connection established", self.id())
diff --git a/tests/handlers/test_federation.py b/tests/handlers/test_federation.py
index d0452e1490..0b24b89a2e 100644
--- a/tests/handlers/test_federation.py
+++ b/tests/handlers/test_federation.py
@@ -126,7 +126,7 @@ class FederationTestCase(unittest.HomeserverTestCase):
             room_version,
         )
 
-        with LoggingContext(request="send_rejected"):
+        with LoggingContext("send_rejected"):
             d = run_in_background(self.handler.on_receive_pdu, OTHER_SERVER, ev)
         self.get_success(d)
 
@@ -178,7 +178,7 @@ class FederationTestCase(unittest.HomeserverTestCase):
             room_version,
         )
 
-        with LoggingContext(request="send_rejected"):
+        with LoggingContext("send_rejected"):
             d = run_in_background(self.handler.on_receive_pdu, OTHER_SERVER, ev)
         self.get_success(d)
 
@@ -198,7 +198,7 @@ class FederationTestCase(unittest.HomeserverTestCase):
         # the auth code requires that a signature exists, but doesn't check that
         # signature... go figure.
         join_event.signatures[other_server] = {"x": "y"}
-        with LoggingContext(request="send_join"):
+        with LoggingContext("send_join"):
             d = run_in_background(
                 self.handler.on_send_join_request, other_server, join_event
             )
diff --git a/tests/logging/test_terse_json.py b/tests/logging/test_terse_json.py
index f6e7e5fdaa..48a74e2eee 100644
--- a/tests/logging/test_terse_json.py
+++ b/tests/logging/test_terse_json.py
@@ -117,11 +117,10 @@ class TerseJsonTestCase(LoggerCleanupMixin, TestCase):
         """
         handler = logging.StreamHandler(self.output)
         handler.setFormatter(JsonFormatter())
-        handler.addFilter(LoggingContextFilter(request=""))
+        handler.addFilter(LoggingContextFilter())
         logger = self.get_logger(handler)
 
-        with LoggingContext() as context_one:
-            context_one.request = "test"
+        with LoggingContext(request="test"):
             logger.info("Hello there, %s!", "wally")
 
         log = self.get_log_line()
@@ -132,9 +131,7 @@ class TerseJsonTestCase(LoggerCleanupMixin, TestCase):
             "level",
             "namespace",
             "request",
-            "scope",
         ]
         self.assertCountEqual(log.keys(), expected_log_keys)
         self.assertEqual(log["log"], "Hello there, wally!")
         self.assertEqual(log["request"], "test")
-        self.assertIsNone(log["scope"])
diff --git a/tests/test_federation.py b/tests/test_federation.py
index fa45f8b3b7..fc9aab32d0 100644
--- a/tests/test_federation.py
+++ b/tests/test_federation.py
@@ -134,7 +134,7 @@ class MessageAcceptTests(unittest.HomeserverTestCase):
             }
         )
 
-        with LoggingContext(request="lying_event"):
+        with LoggingContext():
             failure = self.get_failure(
                 self.handler.on_receive_pdu(
                     "test.serv", lying_event, sent_to_us_directly=True
diff --git a/tests/test_utils/logging_setup.py b/tests/test_utils/logging_setup.py
index fdfb840b62..52ae5c5713 100644
--- a/tests/test_utils/logging_setup.py
+++ b/tests/test_utils/logging_setup.py
@@ -48,7 +48,7 @@ def setup_logging():
     handler = ToTwistedHandler()
     formatter = logging.Formatter(log_format)
     handler.setFormatter(formatter)
-    handler.addFilter(LoggingContextFilter(request=""))
+    handler.addFilter(LoggingContextFilter())
     root_logger.addHandler(handler)
 
     log_level = os.environ.get("SYNAPSE_TEST_LOG_LEVEL", "ERROR")