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diff --git a/Doc/library/logging.rst b/Doc/library/logging.rst index 8092c0e..7f513c4 100644 --- a/Doc/library/logging.rst +++ b/Doc/library/logging.rst @@ -1193,6 +1193,28 @@ are sent to both destinations. This example uses console and file handlers, but you can use any number and combination of handlers you choose. +.. _logging-exceptions: + +Exceptions raised during logging +-------------------------------- + +The logging package is designed to swallow exceptions which occur while logging +in production. This is so that errors which occur while handling logging events +- such as logging misconfiguration, network or other similar errors - do not +cause the application using logging to terminate prematurely. + +:class:`SystemExit` and :class:`KeyboardInterrupt` exceptions are never +swallowed. Other exceptions which occur during the :meth:`emit` method of a +:class:`Handler` subclass are passed to its :meth:`handleError` method. + +The default implementation of :meth:`handleError` in :class:`Handler` checks +to see if a module-level variable, `raiseExceptions`, is set. If set, a +traceback is printed to `sys.stderr`. If not set, the exception is swallowed. + +**Note:** The default value of `raiseExceptions` is `True`. This is because +during development, you typically want to be notified of any exceptions that +occur. It's advised that you set `raiseExceptions` to `False` for production +usage. .. _context-info: |