Make PeriodicallyFlushingMemoryHandler (buffered logging handler which periodically flushes itself) the default logging handler.

changelog.d/10518.feature

@@ -0,0 +1 @@
+The default logging handler for new installations is now `PeriodicallyFlushingMemoryHandler`, a buffered logging handler which periodically flushes itself.

docker/conf/log.config

@@ -22,14 +22,17 @@ handlers:
   # there will be a delay for INFO/DEBUG logs to get written, but WARNING/ERROR
   # logs will still be flushed immediately.
   buffer:
-    class: logging.handlers.MemoryHandler
+    class: synapse.logging.handlers.PeriodicallyFlushingMemoryHandler
     target: file
     # The capacity is the number of log lines that are buffered before
     # being written to disk. Increasing this will lead to better
     # performance, at the expensive of it taking longer for log lines to
     # be written to disk.
     capacity: 10
     flushLevel: 30  # Flush for WARNING logs as well
+    # The period of time, in seconds, between forced flushes.
+    # Messages will not be delayed for longer than this time.
+    period: 5
 {% endif %}
 
   console:

docs/sample_log_config.yaml

@@ -28,14 +28,17 @@ handlers:
     # will be a delay for INFO/DEBUG logs to get written, but WARNING/ERROR
     # logs will still be flushed immediately.
     buffer:
-        class: logging.handlers.MemoryHandler
+        class: synapse.logging.handlers.PeriodicallyFlushingMemoryHandler
         target: file
         # The capacity is the number of log lines that are buffered before
         # being written to disk. Increasing this will lead to better
         # performance, at the expensive of it taking longer for log lines to
         # be written to disk.
         capacity: 10
         flushLevel: 30  # Flush for WARNING logs as well
+        # The period of time, in seconds, between forced flushes.
+        # Messages will not be delayed for longer than this time.
+        period: 5
 
     # A handler that writes logs to stderr. Unused by default, but can be used
     # instead of "buffer" and "file" in the logger handlers.

synapse/config/logger.py

@@ -71,14 +71,17 @@
     # will be a delay for INFO/DEBUG logs to get written, but WARNING/ERROR
     # logs will still be flushed immediately.
     buffer:
-        class: logging.handlers.MemoryHandler
+        class: synapse.logging.handlers.PeriodicallyFlushingMemoryHandler
         target: file
         # The capacity is the number of log lines that are buffered before
         # being written to disk. Increasing this will lead to better
         # performance, at the expensive of it taking longer for log lines to
         # be written to disk.
         capacity: 10
         flushLevel: 30  # Flush for WARNING logs as well
+        # The period of time, in seconds, between forced flushes.
+        # Messages will not be delayed for longer than this time.
+        period: 5
 
     # A handler that writes logs to stderr. Unused by default, but can be used
     # instead of "buffer" and "file" in the logger handlers.