http://www.perlmonks.org?node_id=1043802

skunix has asked for the wisdom of the Perl Monks concerning the following question:

I am polling SNMP data from a list of devices using the SNMP module based off of the Net-SNMP library.

Everything works fine when I make a new SNMP::Session with an IP address that is reachable however if the IP is unreachable the program crashes when I try to get the SNMP data like so...

my $vars = new SNMP::VarList(['sysDescr',0]['sysUpTime',0]);  
my ($descr,$uptime) = $snmp->get($vars);

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Which will crash with the follow error...

Can't call method "get" on an undefined value at...

Is there a way to handle this error without crashing?

Replies are listed 'Best First'.
Re: Perl SNMP Error Handling
by hippo (Bishop) on Jul 11, 2013 at 19:08 UTC

    Of course. Simply test the defined nature of your object before trying to call the method.

    if (defined $snmp) {
  ($descr,$uptime) = $snmp->get($vars);
} else {
  die 'Horrors! My $snmp object is undefined!';
}

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    ... or similar.

[reply]
[d/l]
      Man... I feel like an idiot -_-
[reply]
Re: Perl SNMP Error Handling
by choroba (Cardinal) on Jul 11, 2013 at 19:01 UTC
    You can use eval or Try::Tiny. 
    my ($descr, $uptime);
if (eval { ($descr, $uptime) = $snmp->get($vars); 1 }) {
    ...
} else {
    warn $@;
}

    [download]
    لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ
[reply]
[d/l]

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