logger.py

import os
import sys
import syslog

"""
Logging functionality for SONiC Python applications
"""


class Logger(object):
    """
    Logger class for SONiC Python applications
    """
    LOG_FACILITY_DAEMON = syslog.LOG_DAEMON
    LOG_FACILITY_USER = syslog.LOG_USER

    LOG_OPTION_NDELAY = syslog.LOG_NDELAY
    LOG_OPTION_PID = syslog.LOG_PID

    LOG_PRIORITY_ERROR = syslog.LOG_ERR
    LOG_PRIORITY_WARNING = syslog.LOG_WARNING
    LOG_PRIORITY_NOTICE = syslog.LOG_NOTICE
    LOG_PRIORITY_INFO = syslog.LOG_INFO
    LOG_PRIORITY_DEBUG = syslog.LOG_DEBUG

    DEFAULT_LOG_FACILITY = LOG_FACILITY_USER
    DEFAULT_LOG_OPTION = LOG_OPTION_NDELAY

    def __init__(self, log_identifier=None, log_facility=DEFAULT_LOG_FACILITY, log_option=DEFAULT_LOG_OPTION):
        self._syslog = syslog

        if log_identifier is None:
            log_identifier = os.path.basename(sys.argv[0])

        # Initialize syslog
        self._syslog.openlog(ident=log_identifier, logoption=log_option, facility=log_facility)

        # Set the default minimum log priority to LOG_PRIORITY_NOTICE
        self.set_min_log_priority(self.LOG_PRIORITY_NOTICE)

    def __del__(self):
        self._syslog.closelog()

    #
    # Methods for setting minimum log priority
    #

    def set_min_log_priority(self, priority):
        """
        Sets the minimum log priority level to <priority>. All log messages
        with a priority lower than <priority> will not be logged

        Args:
            priority: The minimum priority at which to log messages
        """
        self._min_log_priority = priority

    def set_min_log_priority_error(self):
        """
        Convenience function to set minimum log priority to LOG_PRIORITY_ERROR
        """
        self.set_min_log_priority(self.LOG_PRIORITY_ERROR)

    def set_min_log_priority_warning(self):
        """
        Convenience function to set minimum log priority to LOG_PRIORITY_WARNING
        """
        self.set_min_log_priority(self.LOG_PRIORITY_WARNING)

    def set_min_log_priority_notice(self):
        """
        Convenience function to set minimum log priority to LOG_PRIORITY_NOTICE
        """
        self.set_min_log_priority(self.LOG_PRIORITY_NOTICE)

    def set_min_log_priority_info(self):
        """
        Convenience function to set minimum log priority to LOG_PRIORITY_INFO
        """
        self.set_min_log_priority(self.LOG_PRIORITY_INFO)

    def set_min_log_priority_debug(self):
        """
        Convenience function to set minimum log priority to LOG_PRIORITY_DEBUG
        """
        self.set_min_log_priority(self.LOG_PRIORITY_DEBUG)

    #
    # Methods for logging messages
    #

    def log(self, priority, msg, also_print_to_console=False):
        if self._min_log_priority >= priority:
            # Send message to syslog
            self._syslog.syslog(priority, msg)

            # Send message to console
            if also_print_to_console:
                print(msg)

    def log_error(self, msg, also_print_to_console=False):
        self.log(self.LOG_PRIORITY_ERROR, msg, also_print_to_console)

    def log_warning(self, msg, also_print_to_console=False):
        self.log(self.LOG_PRIORITY_WARNING, msg, also_print_to_console)

    def log_notice(self, msg, also_print_to_console=False):
        self.log(self.LOG_PRIORITY_NOTICE, msg, also_print_to_console)

    def log_info(self, msg, also_print_to_console=False):
        self.log(self.LOG_PRIORITY_INFO, msg, also_print_to_console)

    def log_debug(self, msg, also_print_to_console=False):
        self.log(self.LOG_PRIORITY_DEBUG, msg, also_print_to_console)