diff --git a/Doc/library/logging.rst b/Doc/library/logging.rst index c78aeb8dcff..58bda370479 100644 --- a/Doc/library/logging.rst +++ b/Doc/library/logging.rst @@ -1316,6 +1316,21 @@ When this script is run, the output should look something like this:: 2008-01-18 14:49:54,033 d.e.f WARNING IP: 127.0.0.1 User: jim A message at WARNING level with 2 parameters +Logging to a single file from multiple processes +------------------------------------------------ + +Although logging is thread-safe, and logging to a single file from multiple +threads in a single process *is* supported, logging to a single file from +*multiple processes* is *not* supported, because there is no standard way to +serialize access to a single file across multiple processes in Python. If you +need to log to a single file from multiple processes, the best way of doing +this is to have all the processes log to a :class:`SocketHandler`, and have a +separate process which implements a socket server which reads from the socket +and logs to file. (If you prefer, you can dedicate one thread in one of the +existing processes to perform this function.) The following section documents +this approach in more detail and includes a working socket receiver which can +be used as a starting point for you to adapt in your own applications. + .. _network-logging: Sending and receiving logging events across a network