Hacky attempt at catching SIGHUP and rotating the logfile around

synapse/config/logger.py

@@ -21,6 +21,7 @@ import logging.config
 import yaml
 from string import Template
 import os
+import signal
 
 
 DEFAULT_LOG_CONFIG = Template("""
@@ -142,6 +143,19 @@ class LoggingConfig(Config):
                 handler = logging.handlers.RotatingFileHandler(
                     self.log_file, maxBytes=(1000 * 1000 * 100), backupCount=3
                 )
+
+                def sighup(signum, stack):
+                    logger.info("Closing log file due to SIGHUP")
+                    handler.doRollover()
+                    logger.info("Opened new log file due to SIGHUP")
+
+                # TODO(paul): obviously this is a terrible mechanism for
+                #   stealing SIGHUP, because it means no other part of synapse
+                #   can use it instead. If we want to catch SIGHUP anywhere
+                #   else as well, I'd suggest we find a nicer way to broadcast
+                #   it around.
+                if getattr(signal, "SIGHUP"):
+                    signal.signal(signal.SIGHUP, sighup)
             else:
                 handler = logging.StreamHandler()
             handler.setFormatter(formatter)