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Sven Nierlein
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Monitoring::Plugin::Functions - functions to simplify the creation of Nagios plugins


    # Constants OK, WARNING, CRITICAL, and UNKNOWN exported by default
    use Monitoring::Plugin::Functions;

    # plugin_exit( CODE, $message ) - exit with error code CODE,
    # and message "PLUGIN CODE - $message"
    plugin_exit( CRITICAL, $critical_error ) if $critical_error;
    plugin_exit( WARNING, $warning_error )   if $warning_error;
    plugin_exit( OK, $result );

    # plugin_die( $message, [$CODE] ) - just like plugin_exit(),
    # but CODE is optional, defaulting to UNKNOWN
      or plugin_die("do_something() failed horribly");
      or plugin_die("do_something_critical() failed", CRITICAL);

    # check_messages - check a set of message arrays, returning a
    # CODE and/or a result message
    $code = check_messages(critical => \@crit, warning => \@warn);
    ($code, $message) = check_messages(
      critical => \@crit, warning => \@warn,
      ok => \@ok );

    # get_shortname - return the default short name for this plugin
    #   (as used by plugin_exit/die; not exported by default)
    $shortname = get_shortname();


This module is part of the Monitoring::Plugin family, a set of modules for simplifying the creation of Nagios plugins. This module exports convenience functions for the class methods provided by Monitoring::Plugin. It is intended for those who prefer a simpler functional interface, and who do not need the additional functionality of Monitoring::Plugin.


Nagios status code constants are exported by default:


as are the following functions:


The following variables and functions are exported only on request:



The following functions are supported:

plugin_exit( <CODE>, $message )

Exit with return code CODE, and a standard nagios message of the form "PLUGIN CODE - $message".

plugin_die( $message, [CODE] )

Same as plugin_exit(), except that CODE is optional, defaulting to UNKNOWN. NOTE: exceptions are not raised by default to calling code. Set $_use_die flag if this functionality is required (see test code).

check_messages( critical => \@crit, warning => \@warn )

Convenience function to check a set of message arrays and return an appropriate nagios return code and/or a result message. Returns only a return code in scalar context; returns a return code and an error message in list context i.e.

    # Scalar context
    $code = check_messages(critical => \@crit, warning => \@warn);
    # List context
    ($code, $msg) = check_messages(critical => \@crit, warning => \@warn);

check_messages() accepts the following named arguments:

critical => ARRAYREF

An arrayref of critical error messages - check_messages() returns CRITICAL if this arrayref is non-empty. Mandatory.

warning => ARRAYREF

An arrayref of warning error messages - check_messages() returns WARNING if this arrayref is non-empty ('critical' is checked first). Mandatory.


An arrayref of informational messages (or a single scalar message), used in list context if both the 'critical' and 'warning' arrayrefs are empty. Optional.

join => SCALAR

A string used to join the relevant array to generate the message string returned in list context i.e. if the 'critical' array @crit is non-empty, check_messages would return:

    join( $join, @crit )

as the result message. Optional; default: ' ' (space).

join_all => SCALAR

By default, only one set of messages are joined and returned in the result message i.e. if the result is CRITICAL, only the 'critical' messages are included in the result; if WARNING, only the 'warning' messages are included; if OK, the 'ok' messages are included (if supplied) i.e. the default is to return an 'errors-only' type message.

If join_all is supplied, however, it will be used as a string to join the resultant critical, warning, and ok messages together i.e. all messages are joined and returned.


Return the default shortname used for this plugin i.e. the first token reported by plugin_exit/plugin_die. The default is basically

    uc basename( $ENV{PLUGIN_NAME} || $ENV{NAGIOS_PLUGIN} || $0 )

with any leading 'CHECK_' and trailing file suffixes removed.

get_shortname is not exported by default, so must be explicitly imported.


Returns the worst state in the array. Order is: CRITICAL, WARNING, OK, UNKNOWN, DEPENDENT

The typical usage of max_state is to initialise the state as UNKNOWN and use it on the result of various test. If no test were performed successfully the state will still be UNKNOWN.


Returns the worst state in the array. Order is: CRITICAL, WARNING, UNKNOWN, DEPENDENT, OK

This is a true definition of a max state (OK last) and should be used if the internal tests performed can return UNKNOWN.


Monitoring::Plugin; the nagios plugin developer guidelines at https://www.monitoring-plugins.org/doc/guidelines.html.


This code is maintained by the Monitoring Plugin Development Team: see https://monitoring-plugins.org


Copyright (C) 2014 by Monitoring Plugin Team Copyright (C) 2006-2014 by Nagios Plugin Development Team

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.