Hello, i asked this question before but didn't get much progress on it. can you see what is wrong here?

i am using snmp and alarm together to timeout a snmp query( to printer ) in mod_perl environment. however, once a timeout happens with an alarm, the next snmp query with a different snmp session always inherit the previous failed snmp query result.

i also use the timeout property in snmp, but it doesn't seem to do anything.

anyway here is code.

{
    foreach $pr_section_name (values %{$config}) {

        my $pr_name = $pr_section_name->{pr_name};
        next unless $pr_name;
        $pr_names{$pr_name}="";
        
        next if $get_pr_names == 1;

        my $cmnt = $pr_section_name->{cmnt};
        my $ip = $pr_section_name->{ip};
        my $lcd_mib_1 = $pr_section_name->{lcd_mib_1};
        my $lcd_mib_2 = $pr_section_name->{lcd_mib_2};

        my ($session, $error) = Net::SNMP->session(
              -hostname  => $ip,
              -community => chomp($cmnt),
              -port      => 161,
              -timeout   => 5,
        );

        if (!defined($session)) {
              print STDERR $error;
              next;
        }

        my $pr_status = &_snmp_query($session,$status_mib) if 
$status_mib;
        my $pr_lcd_msg = &_snmp_query($session,$lcd_msg_mib) if 
$lcd_msg_mib;
        my $lcd_msg_1 = &_snmp_query($session,$lcd_mib_1) if 
$lcd_mib_1;
        my $lcd_msg_2 = &_snmp_query($session,$lcd_mib_2) if 
$lcd_mib_2;
     }
}

# snmp query
sub _snmp_query {
   my ($s,$mib) = @_;
   my $result;

   # printer status
   eval {
        local $SIG{ALRM} = sub { die "alarm\n" };
        alarm 2;
        $result = $s->get_request(
              -varbindlist => [$mib]
        );
        alarm 0;
   };

   if ($@) { 
        return unless $@ eq "alarm\n";
   } else {
        return lc($result->{$mib});
   }
}

[download]

regards,

Qiang

In reply to alarm problem with snmp query by Qiang

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.