sunnyfedora99 has asked for the wisdom of the Perl Monks concerning the following question:

Hi there, I have a small issue. I've written this script which will detect if any interfaces are down on my device. If it's down, give it a WARNING flag, check 4 times again, and if it's still down give it an CRITICAL flag. Could someone please look at my code and give me a heads up of how I can achieve this? 

 
sub check_interfaces {
    
    my $crit = 0;
    my $stat="";
    my $count=0;
    
    my $allInts_OID = ".1.3.6.1.4.1.3375.2.1.2.4.1.2.1.1";
    my $ltm_InBytes_Index = "1.3.6.1.4.1.3375.2.1.2.4.4.3.1.3.";
    my $ltm_OutBytes_Index = "1.3.6.1.4.1.3375.2.1.2.4.4.3.1.5.";
      
    #If $ARGV[2] = 0, then check all interfaces through $allInts_OID. 
    if ($int eq 0) {
    
        my $allInts = $session->get_table ( -baseoid => $allInts_OID )
+;
        my %int_table = %{$allInts};
        #print "\n\n";
        
    OUT:    foreach my $key (sort keys %int_table){
            
            #Convert interface name to OID string
            my @chars = unpack("C" x length($int_table{$key}),$int_tab
+le{$key});
            my $int_length = length( $int_table{$key} );
            unshift(@chars, $int_length);
            my $int_oid = join('.' , @chars);
            
            #Build OID from index & interface
            my $ltm_intBytesIn = $ltm_InBytes_Index . $int_oid;
            my $ltm_intBytesOut = $ltm_OutBytes_Index . $int_oid;
    
            #Get first instance
            my $oids_1 = $session->get_request(
                      -varbindlist =>
                      [$ltm_intBytesIn, $ltm_intBytesOut] );
            
            # Wait for second poll {Keep it 10 seconds}
            #Change after testing
            sleep 5;
    
            #Get second instance
            my $oids_2 = $session->get_request(
                      -varbindlist =>
                      [$ltm_intBytesIn, $ltm_intBytesOut] );
    
            #Calculate Rates
            my $rate_in = ($oids_2->{$ltm_intBytesIn} - $oids_1->{$ltm
+_intBytesIn})*8 / (10*1000000);
            my $rate_out = ($oids_2->{$ltm_intBytesOut} - $oids_1->{$l
+tm_intBytesOut})*8 / (10*1000000);
            my $rate_total = $rate_in + $rate_out;
            
            #Trim to 4 decimal places
            $rate_in =~s/(^\d{1,}\.\d{4})(.*$)/$1/;
            $rate_out =~s/(^\d{1,}\.\d{4})(.*$)/$1/;
            $rate_total =~s/(^\d{1,}\.\d{4})(.*$)/$1/;
    
            #Print Results
            #print "Interface $int_table{$key} rate (Mbits/sec)";
            #print "\n\n\t$rate_in (IN)\n";
            #print "\t$rate_out (OUT)\n";
            #print "\t$rate_total (TOTAL)\n";
            
            my $querystr="select * from device_iface_cache where inter
+face_name='$int_table{$key}' and hostname='$host'";
            my ($f5_ifacerow);
        
            my $query=$dbh->prepare($querystr);
            $query->execute;
            if(!($f5_ifacerow=$query->fetchrow_hashref())) {
                # no row found... insert into f5_selfip
                append_log ("IFace Stats:  No result. Creating a blank
+ record\n");
          
                my $updatestr="INSERT INTO device_iface_cache (interfa
+ce_name, interface_status, lastcheck, hostname) VALUES ('$int_table{$
+key}', '$stat', '$date', '$host');";
                append_log ("IFace Stats: SQL\n");
          
                my $update=$dbh->prepare($updatestr);
                $update->execute;
            }
            
            if($rate_total == $crit){
                #Add in flap detection, also, if an interface is down 
+check x4
                #before alarming.
                $stat = "DOWN";
                append_log ("CRITICAL: Interface $int_table{$key} is D
+OWN.\n");
                append_status("CRITICAL: Interface $int_table{$key} is
+ DOWN.\n");
                
                my $current_status = $dbh->prepare("SELECT interface_s
+tatus FROM device_iface_cache WHERE interface_name='$int_table{$key}'
+ and hostname='$host';");
                $current_status->execute;
                my ($f5_iface_status);
                $f5_iface_status=$current_status->fetchrow_hashref();
                if($f5_iface_status->{interface_status} ne $stat) {
                    
                    my $iface_result = $dbh->prepare("UPDATE device_if
+ace_cache SET interface_status='$stat', lastcheck='$date', hostname='
+$host' WHERE hostname='$host' AND interface_name='$int_table{$key}';"
+);
                    $iface_result->execute();
                    append_log ("STATUS CHANGED: Interface $int_table{
+$key} Was: $f5_iface_status->{interface_status} ------- Now: $stat\n"
+);
                }
            
                my $result = $dbh->prepare("UPDATE device_iface_cache 
+SET interface_status='$stat', lastcheck='$date', hostname='$host' WHE
+RE hostname='$host' AND interface_name='$int_table{$key}';");
                        $result->execute();
            }
            
            #If Status is OK
            if($rate_total > $crit) {
                
                $stat = "UP";   
                append_log ("OK: Interface $int_table{$key} is UP.\n")
+;
                append_status("OK: Interface $int_table{$key} is UP.\n
+");
                
                my $current_status = $dbh->prepare("SELECT interface_s
+tatus FROM device_iface_cache WHERE interface_name='$int_table{$key}'
+ and hostname='$host';");
                $current_status->execute;
                my ($f5_iface_status);
                $f5_iface_status=$current_status->fetchrow_hashref();
                if($f5_iface_status->{interface_status} ne $stat) {
                    
                    my $iface_result = $dbh->prepare("UPDATE device_if
+ace_cache SET interface_status='$stat', lastcheck='$date', hostname='
+$host' WHERE hostname='$host' AND interface_name='$int_table{$key}';"
+);
                    $iface_result->execute();
                    append_log ("STATUS CHANGED: Interface $int_table{
+$key} Was: $f5_iface_status->{interface_status} ------- Now: $stat\n"
+);
                }
                
                my $result = $dbh->prepare("UPDATE device_iface_cache 
+SET interface_status='$stat', lastcheck='$date', hostname='$host' WHE
+RE hostname='$host' AND interface_name='$int_table{$key}';");
                $result->execute();
            }
            
        }

[download]

If the interface is down, it will need to run the check again 4 times, which starts from - LABELLED BLOCK: OUT. Thanks, Sunny

Replies are listed 'Best First'.
Re: Interface flap detection in Perl
by bart (Canon) on Apr 13, 2011 at 12:46 UTC
    It would be a very sane idea to make sure you're using placeholders in all database commands that use parameters. For example, replace 
    my $iface_result = $dbh->prepare("UPDATE device_iface_cache SET interf
+ace_status='$stat', lastcheck='$date', hostname='$host' WHERE hostnam
+e='$host' AND interface_name='$int_table{$key}';");
$iface_result->execute();

    [download]
     with 
    my $iface_result = $dbh->prepare("UPDATE device_iface_cache SET interf
+ace_status=?, lastcheck=? WHERE hostname=? AND interface_name=?");
$iface_result->execute($stat, $date, $host, $int_table{$key});

    [download]
    (no need to set hostname again where you select on it) or even easier, using DBIx::Simple with SQL::Abstract: 
    $db->update('device_iface_cache',
    { interface_status => $stat, lastcheck => $date },
    { hostname => $host, interface_name => $int_table{$key} }
);

    [download]
    (DBIx::Simple uses a database handle that replaces DBI's $dbh, but is not exactly the same thing. Hence the different name $db. You get it by connecting through DBIx::Simple->connect instead of DBI->connect.)
[reply]
[d/l]
[select]

      When I do that on a select statement, i get the following error messages. Use of uninitialized value in string ne at intstatDB.pl line 452. Use of uninitialized value in concatenation (.) or string at intstatDB.pl line 456. 

                  if($rate_total == $crit){
                #Add in flap detection, also, if an interface is down 
+check x4
                #before alarming.
                
                $stat = "DOWN";
                append_log ("CRITICAL: Interface $int_table{$key} is D
+OWN.\n");
                append_status("CRITICAL: Interface $int_table{$key} is
+ DOWN.\n");
                
                my $sth = $dbh->prepare("SELECT interface_status FROM 
+device_iface_cache WHERE interface_name=? and hostname=?");
                $sth->execute($int_table{key}, $host);
                #my $current_status = $dbh->prepare("SELECT interface_
+status FROM device_iface_cache WHERE interface_name='$int_table{$key}
+' and hostname='$host';");
                #$current_status->execute;
                my ($f5_iface_status);
                $f5_iface_status=$sth->fetchrow_hashref();
                #print "$f5_iface_status->{interface_status}\n";
                if($f5_iface_status->{interface_status} ne $stat) {
                    
                    #my $iface_result = $dbh->prepare("UPDATE device_i
+face_cache SET interface_status='$stat', lastcheck='$date', hostname=
+'$host' WHERE hostname='$host' AND interface_name='$int_table{$key}';
+");
                    #$iface_result->execute();
                    my $iface_result = $dbh->prepare("UPDATE device_if
+ace_cache SET interface_status=?, lastcheck=? WHERE hostname=? AND in
+terface_name=?");
                    $iface_result->execute($stat, $date, $host, $int_t
+able{$key});
                    append_log ("STATUS CHANGED: Interface $int_table{
+$key} Was: $f5_iface_status->{interface_status} ------- Now: $stat\n"
+);
                }
            
                my $result = $dbh->prepare("UPDATE device_iface_cache 
+SET interface_status=?, lastcheck=? WHERE hostname=? AND interface_na
+me=?");
                $result->execute($stat, $date, $host, $int_table{$key}
+);
            }

      [download]

      I've used placeholders before as test, and worked fine. Do you know what's going on here.

[reply]
[d/l]
[reply]

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