root / lib / utils / log.py @ 1ae4c5a1
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# Copyright (C) 2006, 2007, 2010, 2011 Google Inc.
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful, but
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# WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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# General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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# 02110-1301, USA.
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"""Utility functions for logging.
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"""
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import logging |
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import logging.handlers |
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from ganeti import constants |
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class LogFileHandler(logging.FileHandler): |
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"""Log handler that doesn't fallback to stderr.
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When an error occurs while writing on the logfile, logging.FileHandler tries
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to log on stderr. This doesn't work in ganeti since stderr is redirected to
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the logfile. This class avoids failures reporting errors to /dev/console.
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"""
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def __init__(self, filename, mode="a", encoding=None): |
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"""Open the specified file and use it as the stream for logging.
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Also open /dev/console to report errors while logging.
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"""
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logging.FileHandler.__init__(self, filename, mode, encoding)
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self.console = open(constants.DEV_CONSOLE, "a") |
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def handleError(self, record): # pylint: disable-msg=C0103 |
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"""Handle errors which occur during an emit() call.
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Try to handle errors with FileHandler method, if it fails write to
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/dev/console.
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"""
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try:
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logging.FileHandler.handleError(self, record)
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except Exception: # pylint: disable-msg=W0703 |
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try:
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self.console.write("Cannot log message:\n%s\n" % self.format(record)) |
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except Exception: # pylint: disable-msg=W0703 |
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# Log handler tried everything it could, now just give up
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pass
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def SetupLogging(logfile, debug=0, stderr_logging=False, program="", |
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multithreaded=False, syslog=constants.SYSLOG_USAGE,
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console_logging=False):
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"""Configures the logging module.
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@type logfile: str
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@param logfile: the filename to which we should log
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@type debug: integer
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@param debug: if greater than zero, enable debug messages, otherwise
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only those at C{INFO} and above level
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@type stderr_logging: boolean
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@param stderr_logging: whether we should also log to the standard error
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@type program: str
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@param program: the name under which we should log messages
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@type multithreaded: boolean
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@param multithreaded: if True, will add the thread name to the log file
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@type syslog: string
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@param syslog: one of 'no', 'yes', 'only':
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- if no, syslog is not used
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- if yes, syslog is used (in addition to file-logging)
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- if only, only syslog is used
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@type console_logging: boolean
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@param console_logging: if True, will use a FileHandler which falls back to
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the system console if logging fails
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@raise EnvironmentError: if we can't open the log file and
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syslog/stderr logging is disabled
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"""
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fmt = "%(asctime)s: " + program + " pid=%(process)d" |
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sft = program + "[%(process)d]:"
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if multithreaded:
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fmt += "/%(threadName)s"
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sft += " (%(threadName)s)"
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if debug:
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fmt += " %(module)s:%(lineno)s"
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# no debug info for syslog loggers
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fmt += " %(levelname)s %(message)s"
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# yes, we do want the textual level, as remote syslog will probably
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# lose the error level, and it's easier to grep for it
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sft += " %(levelname)s %(message)s"
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formatter = logging.Formatter(fmt) |
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sys_fmt = logging.Formatter(sft) |
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root_logger = logging.getLogger("")
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root_logger.setLevel(logging.NOTSET) |
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# Remove all previously setup handlers
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for handler in root_logger.handlers: |
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handler.close() |
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root_logger.removeHandler(handler) |
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if stderr_logging:
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stderr_handler = logging.StreamHandler() |
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stderr_handler.setFormatter(formatter) |
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if debug:
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stderr_handler.setLevel(logging.NOTSET) |
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else:
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stderr_handler.setLevel(logging.CRITICAL) |
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root_logger.addHandler(stderr_handler) |
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if syslog in (constants.SYSLOG_YES, constants.SYSLOG_ONLY): |
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facility = logging.handlers.SysLogHandler.LOG_DAEMON |
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syslog_handler = logging.handlers.SysLogHandler(constants.SYSLOG_SOCKET, |
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facility) |
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syslog_handler.setFormatter(sys_fmt) |
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# Never enable debug over syslog
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syslog_handler.setLevel(logging.INFO) |
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root_logger.addHandler(syslog_handler) |
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if syslog != constants.SYSLOG_ONLY:
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# this can fail, if the logging directories are not setup or we have
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# a permisssion problem; in this case, it's best to log but ignore
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# the error if stderr_logging is True, and if false we re-raise the
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# exception since otherwise we could run but without any logs at all
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try:
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if console_logging:
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logfile_handler = LogFileHandler(logfile) |
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else:
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logfile_handler = logging.FileHandler(logfile) |
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logfile_handler.setFormatter(formatter) |
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if debug:
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logfile_handler.setLevel(logging.DEBUG) |
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else:
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logfile_handler.setLevel(logging.INFO) |
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root_logger.addHandler(logfile_handler) |
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except EnvironmentError: |
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if stderr_logging or syslog == constants.SYSLOG_YES: |
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logging.exception("Failed to enable logging to file '%s'", logfile)
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else:
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# we need to re-raise the exception
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raise
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