nagext.tmpl.py

# Copyright 2010 Alexander Duryagin
#
# This file is part of NagExt.
#
# NagExt is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# NagExt is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with NagExt.  If not, see <http://www.gnu.org/licenses/>.
#

"""
This module provides python interface to Nagios external commands
"""

import os
import stat

from time import time

class ExecError(Exception):
    """
    Errors while executing command (writing external command to command file)
    """
    pass

class NagExt(object):
    """
    Deal with nagios command file for executing external commands.
    Writes commands to Nagios command_file in following format:
    [time] command_id;command_arguments

    """

    def __init__(self, command_file):
        self.command_file = command_file
        self._cmd_f = None
        self.open()

    def __del__(self):
        self.close()

    def open(self):
        """Open Nagios command file

        Raises:
          ExecError: if the file 'command_file' doesn't exist, can't be open
          or is not a pipe (fifo)
        """
        try:
            st = os.stat(self.command_file)
            if not stat.S_ISFIFO(st.st_mode):
                raise IOError('The command file "%s" is not a pipe' %
                              self.command_file)
            self._cmd_f = open(self.command_file, 'w')
        except (OSError, IOError) as e:
            raise ExecError(str(e))

    def close(self):
        """
        Close Nagios command file
        """
        self._cmd_f.close()

    def run(self, cmd, *args):
        """
        Run Nagios external command with given arguments,
        converting bool to int.
        """
        def normalize_args(a):
            if isinstance(a, bool):
                a = int(a)
            return str(a)

        try:
            str_args = ';'.join([normalize_args(a) for a in args])
            self._cmd_f.write("[%lu] %s;%s\n" % (time(), cmd, str_args))
            self._cmd_f.flush()
        except Exception as e:
            raise ExecError(str(e))

    # next follow automatically generated methods from nagios developer documentation
    # for external commands