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author | Vinay Sajip <vinay_sajip@yahoo.co.uk> | 2013-01-07 14:16:52 +0000 |
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committer | Vinay Sajip <vinay_sajip@yahoo.co.uk> | 2013-01-07 14:16:52 +0000 |
commit | e1d00f1d9aed88b910e2fef41d8a270821365e96 (patch) | |
tree | b65f098b72d59caa54a71aadd95b6bb456c7af74 /Doc/library/logging.rst | |
parent | 2ad04c97ffd24a0a9acc856f7910ac565f982644 (diff) | |
download | cpython-e1d00f1d9aed88b910e2fef41d8a270821365e96.tar.gz |
Issue #16884: updated logging documentation to include lastResort and use 'note' directives where appropriate.
Diffstat (limited to 'Doc/library/logging.rst')
-rw-r--r-- | Doc/library/logging.rst | 43 |
1 files changed, 29 insertions, 14 deletions
diff --git a/Doc/library/logging.rst b/Doc/library/logging.rst index b6622e3ead..7a9db728fb 100644 --- a/Doc/library/logging.rst +++ b/Doc/library/logging.rst @@ -928,14 +928,14 @@ functions. Logs a message with level *level* on the root logger. The other arguments are interpreted as for :func:`debug`. - PLEASE NOTE: The above module-level functions which delegate to the root - logger should *not* be used in threads, in versions of Python earlier than - 2.7.1 and 3.2, unless at least one handler has been added to the root - logger *before* the threads are started. These convenience functions call - :func:`basicConfig` to ensure that at least one handler is available; in - earlier versions of Python, this can (under rare circumstances) lead to - handlers being added multiple times to the root logger, which can in turn - lead to multiple messages for the same event. + .. note:: The above module-level functions which delegate to the root + logger should *not* be used in threads, in versions of Python earlier + than 2.7.1 and 3.2, unless at least one handler has been added to the + root logger *before* the threads are started. These convenience functions + call :func:`basicConfig` to ensure that at least one handler is + available; in earlier versions of Python, this can (under rare + circumstances) lead to handlers being added multiple times to the root + logger, which can in turn lead to multiple messages for the same event. .. function:: disable(lvl) @@ -991,12 +991,12 @@ functions. This function does nothing if the root logger already has handlers configured for it. - PLEASE NOTE: This function should be called from the main thread - before other threads are started. In versions of Python prior to - 2.7.1 and 3.2, if this function is called from multiple threads, - it is possible (in rare circumstances) that a handler will be added - to the root logger more than once, leading to unexpected results - such as messages being duplicated in the log. + .. note:: This function should be called from the main thread + before other threads are started. In versions of Python prior to + 2.7.1 and 3.2, if this function is called from multiple threads, + it is possible (in rare circumstances) that a handler will be added + to the root logger more than once, leading to unexpected results + such as messages being duplicated in the log. The following keyword arguments are supported. @@ -1080,6 +1080,21 @@ functions. :kwargs: Additional keyword arguments. +Module-Level Attributes +----------------------- + +.. attribute:: lastResort + + A "handler of last resort" is available through this attribute. This + is a :class:`StreamHandler` writing to ``sys.stderr`` with a level of + ``WARNING``, and is used to handle logging events in the absence of any + logging configuration. The end result is to just print the message to + ``sys.stderr``. This replaces the earlier error message saying that + "no handlers could be found for logger XYZ". If you need the earlier + behaviour for some reason, ``lastResort`` can be set to ``None``. + + .. versionadded:: 3.2 + Integration with the warnings module ------------------------------------ |