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Diffstat (limited to 'cxmanage_api/loggers.py')
| -rw-r--r-- | cxmanage_api/loggers.py | 398 |
1 files changed, 398 insertions, 0 deletions
diff --git a/cxmanage_api/loggers.py b/cxmanage_api/loggers.py new file mode 100644 index 0000000..1e4f4ab --- /dev/null +++ b/cxmanage_api/loggers.py @@ -0,0 +1,398 @@ +# Copyright (c) 2012-2013, Calxeda Inc. +# +# All rights reserved. +# +# Redistribution and use in source and binary forms, with or without +# modification, are permitted provided that the following conditions are +# met: +# +# * Redistributions of source code must retain the above copyright +# notice, this list of conditions and the following disclaimer. +# * Redistributions in binary form must reproduce the above copyright +# notice, this list of conditions and the following disclaimer in the +# documentation and/or other materials provided with the distribution. +# * Neither the name of Calxeda Inc. nor the names of its contributors +# may be used to endorse or promote products derived from this software +# without specific prior written permission. +# +# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS +# FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE +# COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, +# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, +# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS +# OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND +# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR +# TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF +# THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH +# DAMAGE. + + +"""Loggers is a set of Logging classes used to capture output. + +The most commonly used loggers are StandardOutLogger and FileLogger. +Additionally, these loggers can be combined to write output to more than one +target. + +""" + + +import os +import datetime +import traceback + + +# +# Log Level Definitions +# +LL_DEBUG = 4 +LL_INFO = 3 +LL_WARN = 2 +LL_ERROR = 1 +LL_NONE = 0 +DEFAULT_LL = LL_INFO + + +class Logger(object): + """Base class for all loggers. + + To create a custom logger, inherit from this class, and implement + the write() method so that it writes message in the appropriate manner. + + >>> # To use this class for inheritance ... + >>> from cx_automation.loggers import Logger + >>> + + :param log_level: Verbosity level of logging for this logger. + :type log_level: integer + :param time_stamp: Flag to determine toggle time_stamping each log entry. + :type time_stamp: boolean + :param component: Component tag for the log entry. + :type component: string + + .. note:: + * This class is not intended to be used as a logger itself. + * Only the **write()** method needs to be implemeneted for your custom + logger. + * Log Levels: DEBUG=4, INFO=3, WARN=2, ERROR=1, NONE=0 + * You can turn OFF entry time_stamping by initializing a logger with: + **time_stamp=False** + + """ + + def __init__(self, log_level=DEFAULT_LL, time_stamp=True, component=None): + """Default constructor for the Logger class.""" + self.log_level = log_level + self.time_stamp = time_stamp + + if (component): + self.component = '| ' + component + else: + self.component = '' + + def _get_log(self, msg, level_tag): + """Used internally to create an appropriate log message string. + + :param msg: The message to write. + :type msg: string + :param level_tag: The log level string, e.g. INFO, DEBUG, WARN, etc. + :type level_tag: string + + """ + lines = msg.split('\n') + result = [] + for line in lines: + if (self.time_stamp): + ts_now = str(datetime.datetime.now()) + result.append( + '%s %s | %s : %s' % + (ts_now, self.component, level_tag, line) + ) + else: + result.append( + '%s %s : %s' % + (self.component, level_tag, line) + ) + + return '\n'.join(result) + + # pylint: disable=R0201 + def write(self, message): + """Writes a log message. + + .. warning:: + * This method is to be intentionally overridden. + * Implemented by subclasses. + + :param message: The message to write.. + :type message: string + + :raises NotImplementedError: If write() is not overridden. + + """ + del message # For function signature only! + raise NotImplementedError + + def debug(self, message): + """Log a message at DEBUG level. LL_DEBUG = 4 + + >>> logger.debug('This is debug.') + 2012-12-19 11:13:04.329046 | DEBUG | This is debug. + + :param message: The message to write. + :type message: string + + """ + if (self.log_level >= LL_DEBUG): + self.write(self._get_log(message, "DEBUG")) + + def info(self, message): + """Log a message at the INFO level. LL_INFO = 3 + + >>> logger.info('This is informational.') + 2012-12-19 11:11:47.225859 | INFO | This is informational. + + :param message: The message to write. + :type message: string + + """ + if (self.log_level >= LL_INFO): + self.write(self._get_log(msg=message, level_tag="INFO")) + + def warn(self, message): + """Log a message at WARN level. LL_WARN = 2 + + >>> logger.warn('This is a warning') + 2012-12-19 11:11:12.257814 | WARN | This is a warning + + :param message: The message to write. + :type message: string + + """ + if (self.log_level >= LL_WARN): + self.write(self._get_log(msg=message, level_tag="WARN")) + + def error(self, message): + """Log a message at ERROR level. LL_ERROR = 1 + + >>> logger.error('This is an error.') + 2012-12-19 11:14:11.352735 | ERROR | This is an error. + + :param message: The message to write. + :type message: string + + """ + if (self.log_level >= LL_ERROR): + self.write(self._get_log(msg=message, level_tag="ERROR")) + + +class StandardOutLogger(Logger): + """A Logger class that writes to Standard Out (stdout). + + Only the write method has to be implemented. + + >>> # Typical instantiation ... + >>> from cx_automation.loggers import StandardOutLogger + >>> logger = StandardOutLogger() + + + :param log_level: Level of logging for this logger. + :type log_level: integer + :param time_stamp: Flag to determine toggle time_stamping each log entry. + :type time_stamp: boolean + + """ + + def __init__(self, log_level=DEFAULT_LL, time_stamp=True, component=None): + """Default constructor for a StandardOutLogger.""" + self.log_level = log_level + self.time_stamp = time_stamp + self.component = component + super(StandardOutLogger, self).__init__( + log_level=self.log_level, + time_stamp=self.time_stamp, + component=self.component + ) + + def write(self, message): + """Writes a log message to standard out. + + >>> # It simply prints ... + >>> logger.write('This function is called by the Base Class') + This function is called by the Base Class + >>> + + :param message: The message to write. + :type message: string + + """ + print message + + +class FileLogger(Logger): + """A logger that writes to a file. + + >>> # Typical instantiation ... + >>> flogger = FileLogger(abs_path='/home/logfile.out') + + :param log_level: Level of logging for this logger. + :type log_level: integer + :param time_stamp: Flag to determine toggle time_stamping each log entry. + :type time_stamp: boolean + :param name: Name of this logger. + :type name: string + + """ + + def __init__(self, abs_path, time_stamp=True, component=None, + log_level=DEFAULT_LL): + """Default constructor for the FileLogger class.""" + super(FileLogger, self).__init__( + log_level=log_level, + time_stamp=time_stamp, + component=component + ) + self.path = abs_path + try: + if not (os.path.exists(self.path)): + file(self.path, 'w').close() + + except Exception: + raise + + def write(self, message): + """Writes a log message to a log file. + + :param message: The message to write. + :type message: string + + """ + try: + old_umask = os.umask(0000) + with open(self.path, 'a') as file_d: + file_d.write(message + "\n") + file_d.close() + + except Exception: + self.error(traceback.format_exc()) + raise + + finally: + os.umask(old_umask) + if (file_d): + file_d.close() + + +class CompositeLogger(object): + """Takes a list of loggers and writes the same output to them all. + + >>> from cx_automation.loggers import StandardOutLogger, FileLogger + >>> # Let's say you want to log to a file while also seeing the output. + >>> # Create a StandardOutLogger to 'see' output. + >>> slogger = StandarOutLogger(...) + >>> # Create a FileLogger to log to a file. + >>> flogger = FileLogger(...) + >>> from cx_automation.loggers import CompositeLogger + >>> # Create a composite logger and you can log to both simultaneously! + >>> logger = CompositeLogger(loggers=[slogger, flogger]) + + :param loggers: A list of loggers to output to + :type loggers: list + :param log_level: The level to log at. DEFAULT: LL_INFO + :type log_level: integer + + """ + + def __init__(self, loggers, log_level=DEFAULT_LL): + """Default constructor for the CompositeLogger class.""" + self.loggers = loggers + self._log_level = log_level + # + # Set the log level to the same for all loggers ... + # + for logger in self.loggers: + logger.log_level = log_level + + @property + def log_level(self): + """Returns the log_level for ALL loggers. + + >>> logger.log_level + >>> 3 + + :returns: The log_level for ALL loggers. + :rtype: integer + + """ + return self._log_level + + @log_level.setter + def log_level(self, value): + """Sets the log_level for ALL loggers. + + :param value: The value to set the log_level to. + :type value: integer + + """ + self._log_level = value + if (not self._log_level): + return + + for logger in self.loggers: + logger.log_level = value + + def info(self, message): + """Loga a message at the INFO level: LL_INFO = 3 for all loggers. + + >>> logger.info('This is informational.') + 2012-12-19 11:37:17.462879 | INFO | This is informational. + + :param message: The message to write. + :type message: string + + """ + for logger in self.loggers: + logger.info(message) + + def warn(self, message): + """Log a message at WARN level: LL_WARN = 2 for all loggers. + + >>> logger.warn('This is a warning.') + 2012-12-19 11:37:50.614862 | WARN | This is a warning. + + :param message: The message to write. + :type message: string + + """ + for logger in self.loggers: + logger.warn(message) + + def error(self, message): + """Log a message at ERROR level. LL_ERROR = 1 for all loggers. + + >>> logger.error('This is an ERROR!') + 2012-12-19 11:41:18.181123 | ERROR | This is an ERROR! + + :param message: The message to write. + :type message: string + + """ + for logger in self.loggers: + logger.error(message) + + def debug(self, message): + """ + Log a message at DEBUG level. LL_DEBUG = 4 for all loggers. + + >>> logger.debug('This is a DEBUG log entry. Message goes here') + + :param message: The message to write. + :type message: string + + """ + for logger in self.loggers: + logger.debug(message) + + +# End of File: cx_automation/utilites/loggers.py |