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FOREACH Variables

by tx_sailor (Initiate)
on Aug 11, 2009 at 00:35 UTC ( #787452=perlquestion: print w/ replies, xml ) Need Help??
tx_sailor has asked for the wisdom of the Perl Monks concerning the following question:

Greeting Monks,

I am new to PERL so forgive me if this is a trival question. I am building a script to be run via Openview to query an SNMP MIB for get status of an indexed interface. Based on the description of the interface and status, I want to formulate a custom trap.

At this point, I am using Net::SNMP to gain the information from the network device using SNMPv1 (only support by device). Where I am running into trouble is exacting the variables from the FOREACH loop so I can utilize them in a if/else loop. I started from a well know bit of code and modified it.

Here is the code so far:
#!/usr/local/bin/perl # use strict; use Net::SNMP '5.0' || die("Cannot Load SNMP Module\n"); ############################## CONFIGURATION ######################### +######### $snmpnotify = "nnmsnmpnotify.ovpl"; $trap3 = ".1.3.6.1.4.1.13169.9999.0.5"; #Context trap with informatio +n(used by the Pairwise correlation) #$snmp_target = '10.180.89.81'; $snmp_target = ''; $snmp_community = '$@g3on'; ########### Check to see that the number of args is correct ########## +######### if (!($#ARGV == 0)){ exit 1; } $snmp_target = $ARGV[0]; ################################### OIDs ############################# +######### my $oid_ifIndex = '.1.3.6.1.4.1.13169.1.2.10.4.1.1'; my $oid_ifDescr = '.1.3.6.1.4.1.13169.1.2.11.5.1.3'; my $oid_ifOperStatus = '.1.3.6.1.4.1.13169.1.2.10.4.1.2'; my @interfaceList = [$oid_ifDescr, $oid_ifOperStatus]; ################################### CODE ############################# +######### my ($session, $error, $result, @ifindex, $key); my %alarmpoint_status = ( 1 => 'off', 2 => 'on', 3 => 'unknown'); ###################################################################### +######### ## Creation Session ($session, $error) = Net::SNMP->session( -hostname => shift || $snmp_target, -community => shift || $snmp_community, -port => shift || 161, -version => 'snmpv1' ); if (!defined($session)) { printf("ERROR: %s.\n", $error); exit 1; } ## Get AlarmPoint Indexes $result = $session->get_table( -baseoid => $oid_ifIndex ); printf("%s\n", $result ); if (!defined($result)) { printf("ERROR: %s.\n", $session->error); $session->close; exit 1; } foreach $key ($session->var_bind_names) { push(@ifindex, $result->{$key}); } ## Get AlarmPoint Details $result = $session->get_entries( -columns => @interfaceList); printf("%s\n", $result ); if (!defined($result)) { printf("ERROR: %s.\n", $session->error); $session->close; exit 1; } ## Loop through indexes and Output Interface Description and Status foreach $key (@ifindex) { my $alarmd = $result->{$oid_ifDescr.'.'.$key}; my $alarms = $alarmpoint_status{ $result->{$oid_ifOperStatus.'.'. +$key} }; printf("%s : %s\n", $alarmd, $alarms ); } ### Here is where I want to take the value $alarmd and $alarms and uti +lize them in an if state like below: if ($alarms = "off") { $cmd = `$snmpnotify -v 2c -a $snmp_target 10.180.52.58 $trap3 1.3. +6.1.4.1.13169.9999.5.1 OCTETSTRINGASCII $alarmd "Alarm" 1.3.6.1.4.1.1 +3169.9999.5.2 OCTETSTRINGASCII $snmp_target 1.3.6.1.4.1.13169.9999.5. +3 OCTETSTRINGASCII $alarms`; } else {} $session->close;
Any thoughts would be greatly appreciated as I cannot seem to figure this out. Since it is SNMPv1 the getbulk and other options do not work.

Thanks

Rick

Comment on FOREACH Variables
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Re: FOREACH Variables
by NetWallah (Abbot) on Aug 11, 2009 at 01:17 UTC
    Couldn't you just move the "if ($alarms.." inside the "foreach $key.." loop ?

    BTW - why is "use strict;" commented out ?

    You should probably change "foreach $key ..." to "foreach my $key...", and "my $cmd=..." instead of $cmd=..." .. but then you do not use $cmd, so just use the backtick without assigning it to anything.

         Potentia vobiscum ! (Si hoc legere scis nimium eruditionis habes)

Re: FOREACH Variables
by jbt (Chaplain) on Aug 11, 2009 at 03:17 UTC
Re: FOREACH Variables
by snoopy (Deacon) on Aug 11, 2009 at 03:18 UTC
    Also,
    if ($alarms = "off") { #... }
    should be:
    if ($alarms eq "off") { # ... }

      which the OP would have caught with use warnings of course.


      True laziness is hard work
Re: FOREACH Variables
by snoopy (Deacon) on Aug 11, 2009 at 04:43 UTC
    Another catch:
    use Net::SNMP '5.0' || die("Cannot Load SNMP Module\n");
    is interpreted as:
    use Net::SNMP ('5.0' || die("Cannot Load SNMP Module\n"));
    Just stick to:
    use Net::SNMP '5.0';
    Perl will die anyway, if it can't find and load the module.
Re: FOREACH Variables
by cdarke (Prior) on Aug 11, 2009 at 07:41 UTC
    To clarify, $alarms = "off" is an assignment. Use == to test for numeric equality or eq to test for textual equality.

    Always
    use strict; use warnings;
    Although not related to your question, you are over-using printf, which is (allegedly) slower than print. Perl, and several other languages, has interpolation - when a scalar or array variable is enclosed inside double-quotes it translates to its value. This is one of the advantages of the $ and @ prefixes. So:
    printf("%s : %s\n", $alarmd, $alarms );
    is better written as:
    print "$alarmd : $alarms\n";
    and error messages should really be routed to stderr:
    print STDERR "ERROR: $error.\n";

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