An effective SNMP-information-gathering module for perl
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    SNMP::Effective - An effective SNMP-information-gathering module

    This document refers to version 1.06_002 of SNMP::Effective.

    This module will be replace by SNMP::Parallel. Please try it out.

     use SNMP::Effective;
 my $snmp = SNMP::Effective->new(
         max_sessions   => $NUM_POLLERS,
         master_timeout => $TIMEOUT_SECONDS,
         dest_host => $ip,
         callback  => sub { store_data() },
         get       => [ '', 'sysDescr' ],
     # lather, rinse, repeat
 # retrieve data from all hosts

    This module collects information, over SNMP, from many hosts and many
    OIDs, really fast.

    It is a wrapper around the facilities of "", which is the Perl
    interface to the C libraries in the "SNMP" package. Advantages of using
    this module include:

    Simple configuration
        The data structures required by "SNMP" are complex to set up before
        polling, and parse for results afterwards. This module provides a
        simpler interface to that configuration by accepting just a list of
        SNMP OIDs or leaf names.

    Parallel execution
        Many users are not aware that "SNMP" can poll devices asynchronously
        using a callback system. By specifying your callback routine as in
        the "SYNOPSIS" section above, many network devices can be polled in
        parallel, making operations far quicker. Note that this does not use

    It's fast
        To give one example, "SNMP::Effective" can walk, say, eight indexed
        OIDs (port status, errors, traffic, etc) for around 300 devices
        (that's 8500 ports) in under 30 seconds. Storage of that data might
        take an additional 10 seconds (depending on whether it's to RAM or
        disk). This makes polling/monitoring your network every five minutes
        (or less) no problem at all.

    The interface to this module is simple, with few options. The sections
    below detail everything you need to know.

    The method arguments are very flexible. Any of the below acts as the

     $obj->method(MyKey   => $value);
     $obj->method(my_key  => $value);
     $obj->method(My_Key  => $value);
     $obj->method(mYK__EY => $value);

    This is the object constructor, and returns an SNMP::Effective object.

        Maximum number of simultaneous SNMP sessions.

        Maximum number of seconds before killing execute.

    All other arguments are passed on to $snmp_effective->add( ... ).

    Adding information about what SNMP data to get and where to get it.

        Either a single host, or an array-ref that holds a list of hosts.
        The format is whatever "SNMP" can handle.

        A hash-ref of options, passed on to SNMP::Session.

        A reference to a sub which is called after each time a request is

        This can hold anything you want. By default it's an empty hash-ref.

    "get" / "getnext" / "walk"
        Either "oid object", "numeric oid", SNMP::Varbind SNMP::VarList or
        an array-ref containing any combination of the above.

        Either a single SNMP::Varbind or a SNMP::VarList or an array-ref of
        any of the above.

    This can be called with many different combinations, such as:

    "dest_host" / any other argument
        This will make changes per dest_host specified. You can use this to
        change arg, callback or add OIDs on a per-host basis.

    "get" / "getnext" / "walk" / "set"
        The OID list submitted to "add()" will be added to all dest_host, if
        no dest_host is specified.

    "arg" / "callback"
        This can be used to alter all hosts' SNMP arguments or callback

    This method starts setting and/or getting data. It will run as long as
    necessary, or until "master_timeout" seconds has passed. Every time some
    data is set and/or retrieved, it will call the callback-method, as
    defined globally or per host.

     Get/Set the master timeout

     Get/Set the number of max session

    This returns the Log4perl object that is used for logging:

     $self->log->warn("log this message!");

     Returns a list containing all the hosts.

     Returns a hash with the default args

     Returns a ref to the default callback sub-routine.

    Takes a list of numeric OIDs and turns them into an mib-object string.

     make_name_oid(""); # return sysDescr

    Inverse of make_numeric_oid: Takes a list of mib-object strings, and
    turns them into numeric format.

     make_numeric_oid("sysDescr"); # return .

    Takes two arguments: One OID to match against, and the OID to match.

     match_oid("",   "1.3.6");    # return 10
     match_oid("", "1.3.6");    # return 10.1
     match_oid("",   ""); # return undef

The callback method
    When "SNMP" is done collecting data from a host, it calls a callback
    method, provided by the "Callback => sub{}" argument. Here is an example
    of a callback method:

     sub my_callback {
         my($host, $error) = @_
     if($error) {
             warn "$host failed with this error: $error"
     my $data = $host->data;
     for my $oid (keys %$data) {
             print "$host returned oid $oid with this data:\n";
         print join "\n\t",
                   map { "$_ => $data->{$oid}{$_}" }
                       keys %{ $data->{$oid}{$_} };
             print "\n";

    Debugging is enabled through Log::Log4perl. If nothing else is
    spesified, it will default to "error" level, and print to STDERR. The
    component-name you want to change is "SNMP::Effective", inless this
    module ins inherited.

        SNMP::Effective doesn't really do a SNMP native "walk". It makes a
        series of "getnext", which is almost the same as SNMP's walk.

        If you want to use SNMP SET, you have to build your own varbind:

         $varbind = SNMP::VarBind($oid, $iid, $value, $type);
         $effective->add( set => $varbind );

    Improve debugging support

    In addition to the contents of the standard Perl distribution, this
    module requires the following:

        By default the level of reporting is set to "error" and will be
        directed to "STDERR".

        Note that this is not the same as "Net::SNMP" on the CPAN. You want
        the "SNMP" CPAN distribution or the "SNMP" distribution.

        Perl versions greater than 5.7.3 are supplied with this module.

        Perl versions greater than 5.5.0 are supplied with this module.

    "constant" and "overload"
        Perl versions greater than 5.4.0 will have these modules.

    Jan Henning Thorsen, "<pm at>"

    Please report any bugs or feature requests to "bug-snmp-effective at", or through the web interface at
    <>. I will
    be notified, and then you'll automatically be notified of progress on
    your bug as I make changes.

    You can find documentation for this module with the perldoc command.

        perldoc SNMP::Effective

    You can also look for information at:

    *   AnnoCPAN: Annotated CPAN documentation


    *   CPAN Ratings


    *   RT: CPAN's request tracker


    *   Search CPAN


    Various contributions by Oliver Gorwits.

    Sigurd Weisteen Larsen contributed with a better locking mechanism.

    Copyright 2007 Jan Henning Thorsen, all rights reserved.

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