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Diffstat (limited to 'Doc/library')
| -rw-r--r-- | Doc/library/multiprocessing.rst | 58 |
1 files changed, 51 insertions, 7 deletions
diff --git a/Doc/library/multiprocessing.rst b/Doc/library/multiprocessing.rst index 6178851..f3dd23e 100644 --- a/Doc/library/multiprocessing.rst +++ b/Doc/library/multiprocessing.rst @@ -1857,30 +1857,74 @@ handler type) for messages from different processes to get mixed up. Returns the logger used by :mod:`multiprocessing`. If necessary, a new one will be created. - When first created the logger has level :data:`logging.NOTSET` and has a - handler which sends output to :data:`sys.stderr` using format - ``'[%(levelname)s/%(processName)s] %(message)s'``. (The logger allows use of - the non-standard ``'%(processName)s'`` format.) Message sent to this logger - will not by default propagate to the root logger. + When first created the logger has level :data:`logging.NOTSET` and no + default handler. Messages sent to this logger will not by default propagate + to the root logger. Note that on Windows child processes will only inherit the level of the parent process's logger -- any other customization of the logger will not be inherited. +.. currentmodule:: multiprocessing +.. function:: log_to_stderr() + + This function performs a call to :func:`get_logger` but in addition to + returning the logger created by get_logger, it adds a handler which sends + output to :data:`sys.stderr` using format + ``'[%(levelname)s/%(processName)s] %(message)s'``. + Below is an example session with logging turned on:: >>> import multiprocessing, logging - >>> logger = multiprocessing.get_logger() + >>> logger = multiprocessing.log_to_stderr() >>> logger.setLevel(logging.INFO) >>> logger.warning('doomed') [WARNING/MainProcess] doomed >>> m = multiprocessing.Manager() [INFO/SyncManager-1] child process calling self.run() - [INFO/SyncManager-1] manager bound to '\\\\.\\pipe\\pyc-2776-0-lj0tfa' + [INFO/SyncManager-1] created temp directory /.../pymp-Wh47O_ + [INFO/SyncManager-1] manager serving at '/.../listener-lWsERs' >>> del m [INFO/MainProcess] sending shutdown message to manager [INFO/SyncManager-1] manager exiting with exitcode 0 +In addition to having these two logging functions, the multiprocessing also +exposes two additional logging level attributes. These are :const:`SUBWARNING` +and :const:`SUBDEBUG`. The table below illustrates where theses fit in the +normal level hierarchy. + ++----------------+----------------+ +| Level | Numeric value | ++================+================+ +| ``SUBWARNING`` | 25 | ++----------------+----------------+ +| ``SUBDEBUG`` | 5 | ++----------------+----------------+ + +For a full table of logging levels, see the :mod:`logging` module. + +These additional logging levels are used primarily for certain debug messages +within the multiprocessing module. Below is the same example as above, except +with :const:`SUBDEBUG` enabled:: + + >>> import multiprocessing, logging + >>> logger = multiprocessing.log_to_stderr() + >>> logger.setLevel(multiprocessing.SUBDEBUG) + >>> logger.warning('doomed') + [WARNING/MainProcess] doomed + >>> m = multiprocessing.Manager() + [INFO/SyncManager-1] child process calling self.run() + [INFO/SyncManager-1] created temp directory /.../pymp-djGBXN + [INFO/SyncManager-1] manager serving at '/.../pymp-djGBXN/listener-knBYGe' + >>> del m + [SUBDEBUG/MainProcess] finalizer calling ... + [INFO/MainProcess] sending shutdown message to manager + [DEBUG/SyncManager-1] manager received shutdown message + [SUBDEBUG/SyncManager-1] calling <Finalize object, callback=unlink, ... + [SUBDEBUG/SyncManager-1] finalizer calling <built-in function unlink> ... + [SUBDEBUG/SyncManager-1] calling <Finalize object, dead> + [SUBDEBUG/SyncManager-1] finalizer calling <function rmtree at 0x5aa730> ... + [INFO/SyncManager-1] manager exiting with exitcode 0 The :mod:`multiprocessing.dummy` module ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |