Munin contributed plugins

#!/usr/bin/perl -w

=head1 NAME

nginx_hitmiss - Munin plugin to show hit rate of nginx proxy cache

=head1 APPLICABLE SYSTEMS

nginx caching proxy

=head1 CONFIGURATION

File::ReadBackwards is used and must be installed.

You can override the log file location.

  [nginx*]

      env.logfile /var/log/nginx/cache-access.log

Nginx must be configured to include "cs=$upstream_cache_status" in the

log file. Example format:

log_format cache '$remote_addr - $host [$time_local] "$request" $status '

                 '$body_bytes_sent "$http_referer" '

                 'rt=$request_time ut="$upstream_response_time" '

                 'cs=$upstream_cache_status';

By default the last 1000 log lines are read, you may want to change this.

=head1 MAGIC MARKERS

  #%# family=auto

  #%# capabilities=autoconf

=head1 LICENSE

BSD

=cut

use File::ReadBackwards;

my $line_counter=1000;

my $LOG = exists $ENV{'logfile'} ? $ENV{'logfile'}

                                 : "/var/log/nginx/cache-access.log";

if ( exists $ARGV[0] and $ARGV[0] eq "autoconf" ) {

    unless (-r $LOG) {

    print "$LOG not readable\n";

    exit 0;

    } else {

    print "yes\n";

    exit 0;

    }

}

if ( exists $ARGV[0] and $ARGV[0] eq "config" ) {

    print "graph_title NGINX hit rates\n";

    print "graph_args -l 0 -u 100 --rigid\n";

    print "graph_category nginx\n";

    print "graph_vlabel %\n";

    print "hit.label Hits\n";

    print "hit.draw AREA\n";

    print "hit.min 0\n";

    print "hit.cdef hit,$line_counter,/,100,*\n";

    print "miss.label Misses\n";

    print "miss.draw STACK\n";

    print "miss.min 0\n";

    print "miss.cdef miss,$line_counter,/,100,*\n";

    print "expired.label Expired Objects\n";

    print "expired.draw STACK\n";

    print "expired.min 0\n";

    print "expired.cdef expired,$line_counter,/,100,*\n";

    exit 0;

}

my ($e,$h,$m) = (0,0,0);

my $file_counter=0;

FILE: while ($line_counter > 0) {

    my $file_extension = $file_counter==0? "" : ".$file_counter";

    my $lh= File::ReadBackwards->new( "$LOG$file_extension" )

     or ( warn "$line_counter lines to read, but $LOG$file_extension: $!"

          and last FILE);

    $file_counter++;

    while (defined ($_= $lh->readline)) {

        $line_counter--;

        /cs=HIT/     and $h++;

        /cs=MISS/    and $m++;

        /cs=EXPIRED/ and $e++;

        last FILE if $line_counter==0;

    }

    $lh->close();

}

print "hit.value $h\n";

print "miss.value $m\n";

print "expired.value $e\n";