#!/usr/bin/perl
# -*-  perl -*-
#
# $Id: haproxy_errors 79237 2010-01-17 01:18:14Z bvdschans $
# Plugin to monitor haproxy error responses
#
# Author: Bart van der Schans <bart@vanderschans.nl>
#
# Parameters understood:
#
#       config   (required)
#       autoconf (optional - used by munin-config)
#       dump      dump hastats to stdout
#
# Configuration:
# - Make sure the check user can read and write to the unix socket of haproxy
# - Configure the location of the unix socket of haproxy
# - Backends to skip (optional)
#
# Configuration example:
# [haproxy*]
# user haproxy 
# env.socket /var/run/haproxy.sock
# env.skip_backends stats hidden
#
# Magic markers:
#%# family=auto
#%# capabilities=autoconf

use strict;
use Munin::Plugin;
use IO::Socket::UNIX;

my $socketfile = $ENV{'socket'} || '/var/run/haproxy/haproxy.sock';
my @skip_backends = exists $ENV{'skip_backends'} ? split(' ', $ENV{'skip_backends'}) : qw(stats public-http);

# stats hash
my %haproxy;

# parse cmd line
if ( $ARGV[0] eq "autoconf" ) {
    print_autoconf();
    exit 1;
} elsif ( $ARGV[0] eq "config" ) {
    print_config();
    exit 1;
} elsif ( $ARGV[0] eq "dump" ) {
    dump_stats();
    exit 1;
} else {
    print_values();
    exit 1;
}

sub print_values() {
    read_stats();
    for my $pxname (sort keys %haproxy) {
        next if (grep {m|^$pxname?$|} @skip_backends); 
        my $field = clean_fieldname($pxname);
        print "$field.value " . $haproxy{$pxname}{"BACKEND"}{"hrsp_5xx"} . "\n";
    }
}

sub print_config() {
    read_stats();
    print "graph_title errors per backend\n";
    print "graph_args --base 1000\n";
    print "graph_vlabel errors per \${graph_period}\n";
    print "graph_category haproxy\n";
    print "graph_info errors, responses with a 5xx status code, per haproxy backend. This is the sum of the individual backend servers.\n";
    for my $pxname (sort keys %haproxy) {
        next if (grep {m|^$pxname?$|} @skip_backends); 
        my $field = clean_fieldname($pxname);
        print "$field.label $pxname\n";
        print "$field.info number of error responses (5xx) per \${graph_period} per backend.\n";
        print "$field.type DERIVE\n";
        print "$field.min 0\n";
    }
}

sub print_autoconf() {
    if (`/usr/bin/perl $0` eq "" ) {
        print "no\n";
        exit 1;
    } else {
        if ( -S $socketfile ) {
            print "yes\n";
            exit 0;
        } else {
            print "no\n";
            exit 1;
        }
    }
}

sub dump_stats() {
    read_stats();
    foreach my $pxname (sort keys %haproxy) {
        my @svnames = sort keys %{ $haproxy{$pxname} };
        foreach my $svname (@svnames) {
            my %stats = %{ $haproxy{$pxname}{$svname} };
            for my $field (sort keys %stats) {
                print $pxname . "." . $svname . "." . $field . "=" . $stats{$field} .  "\n" if $field;
            }
        }
        print "\n";
    }
}

sub read_stats() {
    unless ( -S $socketfile ) {
        die "Socket not found: $socketfile"
    }
    my $socket = IO::Socket::UNIX->new(Peer  => $socketfile,
                                   Type      => SOCK_STREAM ) or die $!;
    print $socket "show stat\n";
    my @headers;
    while (<$socket>) {
        # skip empty lines
        next if /^\s*$/;
 
        # find headers
        if ( /^\# (.+)/ ) {
            @headers = split(",", $1);
        } else { 
            # build stats hash
            my $i = 0;
            my %stats;
            my @values = split(",");
            my $pxname = @values[0];
            my $svname = @values[1];
            foreach my $value (@values) {
                $stats{@headers[$i]} = $value;
                $i++;
            }
            %{ $haproxy{$pxname}{$svname} } = %stats;
        }
    }
    # cleanup
    $socket->flush;
    $socket->close;
}

# should not be reached
exit -1;