diff --git a/Doc/library/logging.handlers.rst b/Doc/library/logging.handlers.rst index a0129279f4d..f3b26e726aa 100644 --- a/Doc/library/logging.handlers.rst +++ b/Doc/library/logging.handlers.rst @@ -1060,6 +1060,20 @@ possible, while any potentially slow operations (such as sending an email via the record to a dict or JSON string, or send a modified copy of the record while leaving the original intact. + .. note:: The base implementation formats the message with arguments, sets + the ``message`` and ``msg`` attributes to the formatted message and + sets the ``args`` and ``exc_text`` attributes to ``None`` to allow + pickling and to prevent further attempts at formatting. This means + that a handler on the :class:`QueueListener` side won't have the + information to do custom formatting, e.g. of exceptions. You may wish + to subclass ``QueueHandler`` and override this method to e.g. avoid + setting ``exc_text`` to ``None``. Note that the ``message`` / ``msg`` + / ``args`` changes are related to ensuring the record is pickleable, + and you might or might not be able to avoid doing that depending on + whether your ``args`` are pickleable. (Note that you may have to + consider not only your own code but also code in any libraries that + you use.) + .. method:: enqueue(record) Enqueues the record on the queue using ``put_nowait()``; you may