From: Vinay Sajip Date: Sun, 12 Sep 2010 11:47:47 +0000 (+0000) Subject: Issue #9827: clarified LogRecord documentation. X-Git-Tag: v3.1.3rc1~243 X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=2b65fc8aedf19de1d4fb345dbdde5ee9b40e260c;p=python Issue #9827: clarified LogRecord documentation. --- diff --git a/Doc/library/logging.rst b/Doc/library/logging.rst index b5e34ff9d5..bcc1cdaa27 100644 --- a/Doc/library/logging.rst +++ b/Doc/library/logging.rst @@ -540,10 +540,10 @@ Useful Handlers In addition to the base :class:`Handler` class, many useful subclasses are provided: -#. :class:`StreamHandler` instances send error messages to streams (file-like +#. :class:`StreamHandler` instances send messages to streams (file-like objects). -#. :class:`FileHandler` instances send error messages to disk files. +#. :class:`FileHandler` instances send messages to disk files. .. module:: logging.handlers @@ -552,31 +552,31 @@ provided: directly. Instead, use :class:`RotatingFileHandler` or :class:`TimedRotatingFileHandler`. -#. :class:`RotatingFileHandler` instances send error messages to disk +#. :class:`RotatingFileHandler` instances send messages to disk files, with support for maximum log file sizes and log file rotation. -#. :class:`TimedRotatingFileHandler` instances send error messages to +#. :class:`TimedRotatingFileHandler` instances send messages to disk files, rotating the log file at certain timed intervals. -#. :class:`SocketHandler` instances send error messages to TCP/IP +#. :class:`SocketHandler` instances send messages to TCP/IP sockets. -#. :class:`DatagramHandler` instances send error messages to UDP +#. :class:`DatagramHandler` instances send messages to UDP sockets. -#. :class:`SMTPHandler` instances send error messages to a designated +#. :class:`SMTPHandler` instances send messages to a designated email address. -#. :class:`SysLogHandler` instances send error messages to a Unix +#. :class:`SysLogHandler` instances send messages to a Unix syslog daemon, possibly on a remote machine. -#. :class:`NTEventLogHandler` instances send error messages to a +#. :class:`NTEventLogHandler` instances send messages to a Windows NT/2000/XP event log. -#. :class:`MemoryHandler` instances send error messages to a buffer +#. :class:`MemoryHandler` instances send messages to a buffer in memory, which is flushed whenever specific criteria are met. -#. :class:`HTTPHandler` instances send error messages to an HTTP +#. :class:`HTTPHandler` instances send messages to an HTTP server using either ``GET`` or ``POST`` semantics. #. :class:`WatchedFileHandler` instances watch the file they are @@ -675,7 +675,7 @@ functions. d = {'clientip': '192.168.0.1', 'user': 'fbloggs'} logging.warning("Protocol problem: %s", "connection reset", extra=d) - would print something like :: + would print something like:: 2006-02-08 22:20:02,165 192.168.0.1 fbloggs Protocol problem: connection reset @@ -842,6 +842,7 @@ functions. and 2.2.x, which do not include the :mod:`logging` package in the standard library. +.. _logger: Logger Objects -------------- @@ -1441,16 +1442,16 @@ 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. +need to log to a single file from multiple processes, one 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. If you are using a recent version of Python which includes the -:mod:`multiprocessing` module, you can write your own handler which uses the +:mod:`multiprocessing` module, you could write your own handler which uses the :class:`Lock` class from this module to serialize access to the file from your processes. The existing :class:`FileHandler` and subclasses do not make use of :mod:`multiprocessing` at present, though they may do so in the future. @@ -1594,6 +1595,8 @@ these affect you, you can use an alternative serialization scheme by overriding the :meth:`makePickle` method and implementing your alternative there, as well as adapting the above script to use your alternative serialization. +.. _arbitrary-object-messages: + Using arbitrary objects as messages ----------------------------------- @@ -1957,6 +1960,11 @@ timed intervals. The extensions are date-and-time based, using the strftime format ``%Y-%m-%d_%H-%M-%S`` or a leading portion thereof, depending on the rollover interval. + + When computing the next rollover time for the first time (when the handler + is created), the last modification time of an existing log file, or else + the current time, is used to compute when the next rotation will occur. + If the *utc* argument is true, times in UTC will be used; otherwise local time is used. @@ -2452,6 +2460,8 @@ Currently, the useful mapping keys in a :class:`LogRecord` are: +-------------------------+-----------------------------------------------+ | ``%(process)d`` | Process ID (if available). | +-------------------------+-----------------------------------------------+ +| ``%(processName)s`` | Process name (if available). | ++-------------------------+-----------------------------------------------+ | ``%(message)s`` | The logged message, computed as ``msg % | | | args``. | +-------------------------+-----------------------------------------------+ @@ -2465,7 +2475,6 @@ Currently, the useful mapping keys in a :class:`LogRecord` are: specified, ``'%(message)s'`` is used. If no *datefmt* is specified, the ISO8601 date format is used. - .. method:: format(record) The record's attribute dictionary is used as the operand to a string