/ 
SNMP-Effective-1.07
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/ SNMP::Effective

NAME

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

VERSION

1.07

Replacement

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

SYNOPSIS

use SNMP::Effective;

my $snmp = SNMP::Effective->new(
    max_sessions   => $NUM_POLLERS,
    master_timeout => $TIMEOUT_SECONDS,
);

$snmp->add(
    dest_host => $ip,
    callback  => sub { store_data() },
    get       => [ '1.3.6.1.2.1.1.3.0', 'sysDescr' ],
);
# lather, rinse, repeat

# retrieve data from all hosts
$snmp->execute;

DESCRIPTION

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

It is a wrapper around the facilities of SNMP.pm, 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 threads.

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.

METHODS ARGUMENTS

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

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

METHODS

new

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

Arguments

max_sessions

Maximum number of simultaneous SNMP sessions.

mastertimeout

Maximum number of seconds before killing execute.

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

add

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

Arguments

dest_host

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

arg

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

callback

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

heap

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.

set

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 method.

execute

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.

master_timeout

Get/Set the master timeout

max_sessions

Get/Set the number of max session

log

This returns the Log4perl object that is used for logging:

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

hostlist

Returns a list containing all the hosts.

arg

Returns a hash with the default args

callback

Returns a ref to the default callback sub-routine.

FUNCTIONS

make_name_oid

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

make_name_oid("1.3.6.1.2.1.1.1"); # return sysDescr

make_numeric_oid

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

make_numeric_oid("sysDescr"); # return .1.3.6.1.2.1.1.1

match_oid

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

match_oid("1.3.6.10",   "1.3.6");    # return 10
match_oid("1.3.6.10.1", "1.3.6");    # return 10.1
match_oid("1.3.6.10",   "1.3.6.11"); # 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"
        return;
    }

    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

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.

NOTES

walk

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.

set

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 );

TODO

Improve debugging support

DEPENDENCIES

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

Log::Log4perl

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

SNMP

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

Time::HiRes

Perl versions greater than 5.7.3 are supplied with this module.

Tie::Array

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.

AUTHOR

Jan Henning Thorsen, <pm at flodhest.net>

BUGS

Please report any bugs or feature requests to bug-snmp-effective at rt.cpan.org, or through the web interface at http://rt.cpan.org/NoAuth/ReportBug.html?Queue=SNMP-Effective. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.

SUPPORT

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

perldoc SNMP::Effective

You can also look for information at:

ACKNOWLEDGEMENTS

Various contributions by Oliver Gorwits.

Sigurd Weisteen Larsen contributed with a better locking mechanism.

COPYRIGHT & LICENSE

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.