Dear Monks,

Here goes:

We have around 3000 routers and a configuration database with entries created when the devices are commissioned. In order to ensure the integrity and accuracy of the recorded data I have a bash shell script that grabs the list of all devices and a few config variables (such as community strings, device type, line speed etc) and then double checks the validity of the config against the live device settings.

I am in the process of converting to Perl (from the original, and very slow bash script).

(Obviously, "perl -w" and "use strict" are used!)

So, I grab the list using LWP: 

my $browser     = LWP::UserAgent->new();
my $source_data = $browser->get( $config{source_file} );
die( "Couldn't GET $config{source_file}\n" ) unless defined $source_da
+ta;
print "Got source data\n";
my $results_table;

my @all_results = split /\n/, $source_data->{_content};

for ( @all_results ) {
 next if $_ =~ m/^\#/;
 my ( $site_name, $line_speed, $mgmt_ip, $switch_port, $ro_community, 
+$group,
      $site_code )
   = split /\|/;

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I then populate a HoH: 
$results_table->{$group}->{$site_name} = {
                                            line_speed   => $line_spee
+d,
                                            mgmt_ip      => $mgmt_ip,
                                            switch_port  => $switch_po
+rt,
                                            ro_community => $ro_commun
+ity,
                                            site_code    => $site_code
+,
                                            oss_device   => $oss_devic
+e,
                                            snmp_status => '',
                                            sysobjid => '',
                                          };

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At this point I set up non-blocking Net::SNMP sessions and use callback to launch a subfunction to, in this example, add the mib2 sysobjid to the HoH: 

   my ($session, $error) = Net::SNMP->session(
      -community => $results_table->{$group}->{$site_name}->{ro_commun
+ity},
      -hostname    => $results_table->{$group}->{$site_name}->{mgmt_ip
+},
      -nonblocking => 0x1,   # Create non-blocking objects
                         );
   if (!defined($session)) {
      printf("ERROR: %s.\n", $error);
      exit 1;
   }

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And: 
   $session->get_request(

       -varbindlist => [ $oids{sysobjid} ],
       -callback    => [ \&store_sysobjid, \$group, \$site_name ]
   );

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Now, close the for loop and get the ball rolling: 
}
snmp_dispatcher();

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The subfunction: 
sub store_sysobjid
{
my ($session, $group, $site_name ) = @_;
   if (!defined($session->var_bind_list)) {
   $results_table->{$$group}}->{$$site_name} = {
                                                sysobjid => "unknown",
                                                snmp_status => "NOT OK
+",
                                            };

   printf("%-15s  ERROR: %s\n", $session->hostname, $session->error);

   } else {
   $results_table->{$$group}->{$$site_name} = {
                                                sysobjid => ${$session
+->var_bind_list}{$oids{sysobjid}},
                                                snmp_status => "OK"};
    }
}

[download]

Now, it has taken me a little while to get the referencing / dereferencing syntax working correctly but this seems OK now.

My questions:

1. When I use Data::Dumper to get the contents of \$results_table the sysbojid and snmp_status variables seem to have zapped the rest of the data on the HoH for that site out of existence. Is the syntax incorrect? If I remove the sysobjid => unknown code then any site that is down (i.e. has its snmp allowed managers configured incorrectly) retains the line_speed / mgmt_ip data correctly.

2. Is using a HoH an appropriate approach? My thoughts were to use a HoH so that when I have all of the data I can chuck out all of the relevant HTML pages quite easily.

FYI - Using non-blocking Net::SNMP has reduced the runtime of this from around 20-30 minutes for the shell script (which ran serially) to around 24 seconds (WoooHooo!)

Any comments / suggestions / criticisms are more than welcome.

I am here to learn.

Thanks

smullis

In reply to Hash of Hashes, referencing, dereferencing and Net::SNMP by smullis

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