diff options
| -rw-r--r-- | changelog.d/16314.misc | 1 | ||||
| -rw-r--r-- | synapse/metrics/background_process_metrics.py | 21 |
2 files changed, 21 insertions, 1 deletions
diff --git a/changelog.d/16314.misc b/changelog.d/16314.misc new file mode 100644 index 0000000000..a32b07112a --- /dev/null +++ b/changelog.d/16314.misc @@ -0,0 +1 @@ +Remove a reference cycle for in background processes. diff --git a/synapse/metrics/background_process_metrics.py b/synapse/metrics/background_process_metrics.py index 9ea4e23b31..f1f1f0cdf9 100644 --- a/synapse/metrics/background_process_metrics.py +++ b/synapse/metrics/background_process_metrics.py @@ -322,13 +322,21 @@ class BackgroundProcessLoggingContext(LoggingContext): if instance_id is None: instance_id = id(self) super().__init__("%s-%s" % (name, instance_id)) - self._proc = _BackgroundProcess(name, self) + self._proc: Optional[_BackgroundProcess] = _BackgroundProcess(name, self) def start(self, rusage: "Optional[resource.struct_rusage]") -> None: """Log context has started running (again).""" super().start(rusage) + if self._proc is None: + logger.error( + "Background process re-entered without a proc: %s", + self.name, + stack_info=True, + ) + return + # We've become active again so we make sure we're in the list of active # procs. (Note that "start" here means we've become active, as opposed # to starting for the first time.) @@ -345,6 +353,14 @@ class BackgroundProcessLoggingContext(LoggingContext): super().__exit__(type, value, traceback) + if self._proc is None: + logger.error( + "Background process exited without a proc: %s", + self.name, + stack_info=True, + ) + return + # The background process has finished. We explicitly remove and manually # update the metrics here so that if nothing is scraping metrics the set # doesn't infinitely grow. @@ -352,3 +368,6 @@ class BackgroundProcessLoggingContext(LoggingContext): _background_processes_active_since_last_scrape.discard(self._proc) self._proc.update_metrics() + + # Set proc to None to break the reference cycle. + self._proc = None |