#!/usr/bin/perl -w

=head CONFIGURATION

    Based on Redis module code v0.08 2009/from http://svn.rot13.org/index.cgi/Redis

    Installation process:

    1. Download the plugin to your plugins directory (e.g. /usr/share/munin/plugins)
    2. Symlink it to your configuration directory (e.g. ln -s /usr/share/munin/plugins/redis /etc/munin/plugins/redis)
    3. Edit plugin-conf.d/munin-node with the options to connect to your redis instances (see below for an example)
    4. Restart munin-node service

    Example config
    [redis]
    env.host1 127.0.0.1
    env.port1 6379
    env.password1 password
    env.title_prefix1 redis-1
    env.host2 /run/redis.sock
    env.title_prefix2 redis-2

    Each host should be specified with at least a host or unixsocket variable suffixed with
    a number, the first being 1, the second being 2 etc. They must be in sequence.
    Other options are:
    * port - the redis port to connect to
    * password - the password to use with the AUTH command
    * title_prefix - a prefix to put before the title of the graph, this is strongly recommended for multiple instances

    Graphs:
    This generates multigraphs for:
    * Connected clients
    * Key Hit vs Miss ratio
    * Keys per second, hits/misses/expirations/evictions
    * Replication backlog
    * Replication lag
    * Request per second
    * Total number of keys and keys with expires
    * Used memory

=head COPYRIGHT

    Copyright (C) 2020 Rowan Wookey <https://www.rwky.net/>
    Copyright (C) 2009 Gleb Voronich <http://stanly.net.ua/>

=head LICENSE

    This program is free software; you can redistribute it and/or
    modify it under the terms of the GNU General Public License
    as published by the Free Software Foundation; version 2 dated June,
    1991.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

=head MAGIC MARKERS

    #%# family=auto
    #%# capabilities=autoconf

=cut

use strict;
use IO::Socket::INET;
use IO::Socket::UNIX;

my %INSTANCES;
my $HOST;
my $PORT;
my $PASSWORD;

for (my $i = 1; $ENV{"host$i"}; $i++)
{
    $HOST = exists $ENV{"host$i"} ? $ENV{"host$i"} : "127.0.0.1";
    $PORT = exists $ENV{"port$i"} ? $ENV{"port$i"} : 6379;
    $PASSWORD = exists $ENV{"password$i"} ? $ENV{"password$i"} : undef;
    my $TITLE_PREFIX = exists $ENV{"title_prefix$i"} ? $ENV{"title_prefix$i"} . ": " : "";
    my $SOCK = &get_conn();
    $INSTANCES{"instance$i"} = {
        HOST => $HOST,
        PORT => $PORT,
        PASSWORD => $PASSWORD,
        TITLE_PREFIX => $TITLE_PREFIX,
        SOCK => $SOCK
    };
}


my $config = ( defined $ARGV[0] and $ARGV[0] eq "config" );
my $autoconf = ( defined $ARGV[0] and $ARGV[0] eq "autoconf" );
if ( $autoconf ) {
    if (!%INSTANCES) {
        print "no (no redis instances configured)\n";
        exit 0;
    }
    my $err = '';
    for my $INSTANCE (keys %INSTANCES) {
        if (! defined( $INSTANCES{$INSTANCE}{'SOCK'} ) ) {
            $err = "no (unable to connect to ".$INSTANCES{$INSTANCE}{'HOST'}."\[:". $INSTANCES{$INSTANCE}{'PORT'}."\])\n";
        }
    }
    if ($err) {
        print $err;
    } else {
        print "yes\n";
    }
    exit 0;
}

my $total = 0;

my $multi_graph_output = '';
my $instance_graph_output = '';

my $connected_clients = 0;
my $keyspace_hits = 0;
my $keyspace_misses = 0;
my $expired_keys = 0;
my $evicted_keys = 0;
my $total_commands_processed = 0;
my $total_connections_received = 0;
my $repl_backlog_size = 0;
my $used_memory = 0;
my $used_memory_rss = 0;
my $used_memory_peak = 0;
my $total_keys = 0;
my $total_expires = 0;
foreach my $INSTANCE (keys %INSTANCES) {

    my $sock = $INSTANCES{$INSTANCE}{'SOCK'};
    my $TITLE_PREFIX = $INSTANCES{$INSTANCE}{'TITLE_PREFIX'};
    my $hash = get_info($sock);

    my $dbs;
    foreach my $key (keys %{$hash}) {
        if ( $key =~ /^db\d+$/ && $hash->{$key} =~ /keys=(\d+),expires=(\d+)/ ) {
            $total_keys += $1;
            $total_expires += $2;
            $dbs->{$key} = [ $1, $2 ];
        }
    }

    if ( $config ) {
        my $ret = get_config("maxclients", $sock);
        # if the CONFIG command is disabled we don't show the max clients
        my $maxclients = defined $ret ? $ret->{"maxclients"} : 0;
        $instance_graph_output .=  "multigraph redis_connected_clients.$INSTANCE\n";
        $instance_graph_output .=  "graph_title ${TITLE_PREFIX}Connected clients\n";
        $instance_graph_output .=  "graph_vlabel Connected clients\n";
        $instance_graph_output .=  "graph_category db\n";
        $instance_graph_output .=  "graph_args -l 0\n";
        if ($maxclients) {
            $instance_graph_output .=  "connected_clients.line $maxclients:ff0000:Limit\n";
        }
        $instance_graph_output .=  "connected_clients.label connected clients\n";
        $instance_graph_output .=  "multigraph keys_per_sec.$INSTANCE\n";
        $instance_graph_output .=  "graph_title ${TITLE_PREFIX}Keys Per Second\n";
        $instance_graph_output .=  "graph_vlabel per \${graph_period}\n";
        $instance_graph_output .=  "graph_category db\n";
        $instance_graph_output .=  "graph_args -l 0\n";
        $instance_graph_output .=  "hits.label hits\n";
        $instance_graph_output .=  "hits.type COUNTER\n";
        $instance_graph_output .=  "misses.label misses\n";
        $instance_graph_output .=  "misses.type COUNTER\n";
        $instance_graph_output .=  "expired.label expirations\n";
        $instance_graph_output .=  "expired.type COUNTER\n";
        $instance_graph_output .=  "evicted_keys.label evictions\n";
        $instance_graph_output .=  "evicted_keys.type COUNTER\n";
        $instance_graph_output .=  "multigraph redis_key_ratio.$INSTANCE\n";
        $instance_graph_output .=  "graph_title ${TITLE_PREFIX}Key Hit vs Miss Ratio\n";
        $instance_graph_output .=  "graph_vlabel per \${graph_period}\n";
        $instance_graph_output .=  "graph_category db\n";
        $instance_graph_output .=  "graph_args -u 100 -l 0 -r --base 1000\n";
        $instance_graph_output .=  "hitratio.label hit ratio\n";
        $instance_graph_output .=  "hitratio.type GAUGE\n";
        $instance_graph_output .=  "hitratio.draw AREA\n";
        $instance_graph_output .=  "missratio.label miss ratio\n";
        $instance_graph_output .=  "missratio.type GAUGE\n";
        $instance_graph_output .=  "missratio.draw STACK\n";
        $instance_graph_output .=  "multigraph redis_per_sec.$INSTANCE\n";
        $instance_graph_output .=  "graph_title ${TITLE_PREFIX}Requests Per second\n";
        $instance_graph_output .=  "graph_vlabel per \${graph_period}\n";
        $instance_graph_output .=  "graph_category db\n";
        $instance_graph_output .=  "graph_args -l 0\n";
        $instance_graph_output .=  "requests.label requests\n";
        $instance_graph_output .=  "requests.type COUNTER\n";
        $instance_graph_output .=  "connections.label connections\n";
        $instance_graph_output .=  "connections.type COUNTER\n";
        $instance_graph_output .=  "multigraph redis_repl_backlog_size.$INSTANCE\n";
        $instance_graph_output .=  "graph_title ${TITLE_PREFIX}replication backlog\n";
        $instance_graph_output .=  "graph_vlabel replication backlog\n";
        $instance_graph_output .=  "graph_category db\n";
        $instance_graph_output .=  "graph_args -l 0\n";
        $instance_graph_output .=  "repl_backlog_size.label bytes behind master\n";
        $instance_graph_output .=  "multigraph redis_repl_lag.$INSTANCE\n";
        $instance_graph_output .=  "graph_title ${TITLE_PREFIX}replication lag\n";
        $instance_graph_output .=  "graph_vlabel replication lag\n";
        $instance_graph_output .=  "graph_category db\n";
        $instance_graph_output .=  "graph_args -l 0\n";
        $instance_graph_output .=  "repl_backlog_size.label amount behind master\n";
        # if the CONFIG command is disabled we don't show maxmemory
        $ret = get_config("maxmemory", $sock);
        my $maxmemory = defined $ret ? $ret->{"maxmemory"} : 0;
        $instance_graph_output .=  "multigraph redis_used_memory.$INSTANCE\n";
        $instance_graph_output .=  "graph_title ${TITLE_PREFIX}Used memory\n";
        $instance_graph_output .=  "graph_vlabel Used memory\n";
        $instance_graph_output .=  "graph_category db\n";
        $instance_graph_output .=  "graph_args -l 0 --base 1024\n";
        if ($maxmemory) {
            $instance_graph_output .=  "used_memory.line $maxmemory:ff0000:Limit\n";
        }
        $instance_graph_output .=  "used_memory.label used memory\n";
        $instance_graph_output .=  "used_memory_peak.label used memory in peak\n";
        $instance_graph_output .=  "used_memory_rss.label Resident set size memory usage\n";
        $instance_graph_output .=  "multigraph redis_used_keys.$INSTANCE\n";
        $instance_graph_output .=  "graph_title ${TITLE_PREFIX}Used keys\n";
        $instance_graph_output .=  "graph_vlabel Used keys\n";
        $instance_graph_output .=  "graph_category db\n";
        $instance_graph_output .=  "graph_args -l 0\n";

        foreach my $db (keys %{$dbs}) {
            $instance_graph_output .= sprintf "%s_keys.label %s keys\n", $db, $db;
            $instance_graph_output .= sprintf "%s_expires.label %s expires\n", $db, $db;
        }

        next;
    }

    $instance_graph_output .=  "multigraph redis_connected_clients.$INSTANCE\n";
    $instance_graph_output .=  "connected_clients.value " . $hash->{'connected_clients'} . "\n";
    $connected_clients += $hash->{'connected_clients'};
    $instance_graph_output .=  "multigraph keys_per_sec.$INSTANCE\n";
    $instance_graph_output .=  "hits.value " . $hash->{'keyspace_hits'} . "\n";
    $keyspace_hits += $hash->{'keyspace_hits'};
    $instance_graph_output .=  "misses.value " . $hash->{'keyspace_misses'} . "\n";
    $keyspace_misses += $hash->{'keyspace_misses'};
    $instance_graph_output .=  "expired.value " . $hash->{'expired_keys'} . "\n";
    $expired_keys += $hash->{'expired_keys'};
    $instance_graph_output .=  "evicted_keys.value " . $hash->{'evicted_keys'} . "\n";
    $evicted_keys += $hash->{'evicted_keys'};
    $instance_graph_output .=  "multigraph redis_key_ratio.$INSTANCE\n";
    my $total = $hash->{'keyspace_hits'} + $hash->{'keyspace_misses'};
    my $hitratio = 0;
    my $missratio = 0;
    if ($total > 0) {
        $hitratio = $hash->{'keyspace_hits'} / $total * 100;
        $missratio = $hash->{'keyspace_misses'} / $total * 100;
    }
    $instance_graph_output .= sprintf("hitratio.value %.2f\n", $hitratio);
    $instance_graph_output .= sprintf("missratio.value %.2f\n", $missratio);
    $instance_graph_output .=  "multigraph redis_per_sec.$INSTANCE\n";
    $instance_graph_output .=  "requests.value ". $hash->{'total_commands_processed'} ."\n";
    $total_commands_processed += $hash->{'total_commands_processed'};
    $instance_graph_output .=  "connections.value ". $hash->{'total_connections_received'} ."\n";
    $total_connections_received += $hash->{'total_connections_received'};
    $instance_graph_output .=  "multigraph redis_repl_backlog_size.$INSTANCE\n";
    $instance_graph_output .=  "repl_backlog_size.value " . $hash->{'repl_backlog_size'} . "\n";
    $repl_backlog_size += $hash->{'repl_backlog_size'};

    $instance_graph_output .=  "multigraph redis_repl_lag.$INSTANCE\n";
    if (exists $hash->{slave0} && $hash->{slave0} =~ /lag=(\d+)/) {
        $repl_backlog_size += $1;
        $instance_graph_output .=  "repl_backlog_size.value " . $1 . "\n";
    } else {
        $instance_graph_output .=  "repl_backlog_size.value 0\n";
    }


    $instance_graph_output .=  "multigraph redis_used_memory.$INSTANCE\n";
    $instance_graph_output .=  "used_memory.value ". $hash->{'used_memory'}  ."\n";

    $used_memory += $hash->{'used_memory'};
    $instance_graph_output .=  "used_memory_rss.value ". $hash->{'used_memory_rss'}  ."\n";
    $used_memory_rss += $hash->{'used_memory_rss'};
    $instance_graph_output .=  "used_memory_peak.value ". $hash->{'used_memory_peak'}  ."\n";
    $used_memory_peak += $hash->{'used_memory_peak'};

    $instance_graph_output .=  "multigraph redis_used_keys.$INSTANCE\n";
    foreach my $db (keys %{$dbs}) {
        $instance_graph_output .= sprintf "%s_keys.value %d\n", $db, $dbs->{$db}[0];
        $instance_graph_output .= sprintf "%s_expires.value %d\n", $db, $dbs->{$db}[1];
    }
    close ($sock);
}

# multigraph output
if ($config) {
    $multi_graph_output .=  "multigraph redis_connected_clients\n";
    $multi_graph_output .=  "graph_title Connected clients\n";
    $multi_graph_output .=  "graph_vlabel Connected clients\n";
    $multi_graph_output .=  "graph_category db\n";
    $multi_graph_output .=  "graph_args -l 0\n";
    $multi_graph_output .=  "connected_clients.label connected clients\n";
    $multi_graph_output .=  "multigraph keys_per_sec\n";
    $multi_graph_output .=  "graph_title Keys Per Second\n";
    $multi_graph_output .=  "graph_vlabel per \${graph_period}\n";
    $multi_graph_output .=  "graph_category db\n";
    $multi_graph_output .=  "graph_args -l 0\n";
    $multi_graph_output .=  "hits.label hits\n";
    $multi_graph_output .=  "hits.type COUNTER\n";
    $multi_graph_output .=  "misses.label misses\n";
    $multi_graph_output .=  "misses.type COUNTER\n";
    $multi_graph_output .=  "expired.label expirations\n";
    $multi_graph_output .=  "expired.type COUNTER\n";
    $multi_graph_output .=  "evicted_keys.label evictions\n";
    $multi_graph_output .=  "evicted_keys.type COUNTER\n";
    $multi_graph_output .=  "multigraph redis_key_ratio\n";
    $multi_graph_output .=  "graph_title Key Hit vs Miss Ratio\n";
    $multi_graph_output .=  "graph_vlabel per \${graph_period}\n";
    $multi_graph_output .=  "graph_category db\n";
    $multi_graph_output .=  "graph_args -u 100 -l 0 -r --base 1000\n";
    $multi_graph_output .=  "hitratio.label hit ratio\n";
    $multi_graph_output .=  "hitratio.type GAUGE\n";
    $multi_graph_output .=  "hitratio.draw AREA\n";
    $multi_graph_output .=  "missratio.label miss ratio\n";
    $multi_graph_output .=  "missratio.type GAUGE\n";
    $multi_graph_output .=  "missratio.draw STACK\n";
    $multi_graph_output .=  "multigraph redis_per_sec\n";
    $multi_graph_output .=  "graph_title Requests Per second\n";
    $multi_graph_output .=  "graph_vlabel per \${graph_period}\n";
    $multi_graph_output .=  "graph_category db\n";
    $multi_graph_output .=  "graph_args -l 0\n";
    $multi_graph_output .=  "requests.label requests\n";
    $multi_graph_output .=  "requests.type COUNTER\n";
    $multi_graph_output .=  "connections.label connections\n";
    $multi_graph_output .=  "connections.type COUNTER\n";
    $multi_graph_output .=  "multigraph redis_repl_backlog_size\n";
    $multi_graph_output .=  "graph_title replication backlog\n";
    $multi_graph_output .=  "graph_vlabel replication backlog\n";
    $multi_graph_output .=  "graph_category db\n";
    $multi_graph_output .=  "graph_args -l 0\n";
    $multi_graph_output .=  "repl_backlog_size.label bytes behind master\n";
    $multi_graph_output .=  "multigraph redis_repl_lag\n";
    $multi_graph_output .=  "graph_title replication lag\n";
    $multi_graph_output .=  "graph_vlabel replication lag\n";
    $multi_graph_output .=  "graph_category db\n";
    $multi_graph_output .=  "graph_args -l 0\n";
    $multi_graph_output .=  "repl_backlog_size.label amount behind master\n";
    $multi_graph_output .=  "multigraph redis_used_memory\n";
    $multi_graph_output .=  "graph_title Used memory\n";
    $multi_graph_output .=  "graph_vlabel Used memory\n";
    $multi_graph_output .=  "graph_category db\n";
    $multi_graph_output .=  "graph_args -l 0 --base 1024\n";
    $multi_graph_output .=  "used_memory.label used memory\n";
    $multi_graph_output .=  "used_memory_peak.label used memory in peak\n";
    $multi_graph_output .=  "used_memory_rss.label Resident set size memory usage\n";
    $multi_graph_output .=  "multigraph redis_used_keys\n";
    $multi_graph_output .=  "graph_title Used keys\n";
    $multi_graph_output .=  "graph_vlabel Used keys\n";
    $multi_graph_output .=  "graph_category db\n";
    $multi_graph_output .=  "graph_args -l 0\n";
    $multi_graph_output .=  "total_keys.label Total keys\n";
    $multi_graph_output .=  "total_expires.label Total expires\n";
} else {

    $multi_graph_output .=  "multigraph redis_connected_clients\n";
    $multi_graph_output .=  "connected_clients.value " . $connected_clients . "\n";
    $multi_graph_output .=  "multigraph keys_per_sec\n";
    $multi_graph_output .=  "hits.value " . $keyspace_hits . "\n";
    $multi_graph_output .=  "misses.value " . $keyspace_misses . "\n";
    $multi_graph_output .=  "expired.value " . $expired_keys . "\n";
    $multi_graph_output .=  "evicted_keys.value " . $evicted_keys . "\n";
    $multi_graph_output .=  "multigraph redis_key_ratio\n";
    my $total = $keyspace_hits + $keyspace_misses;
    my $hitratio = 0;
    my $missratio = 0;
    if ($total > 0) {
        $hitratio = $keyspace_hits / $total * 100;
        $missratio = $keyspace_misses / $total * 100;
    }
    $multi_graph_output .= sprintf("hitratio.value %.2f\n", $hitratio);
    $multi_graph_output .= sprintf("missratio.value %.2f\n", $missratio);
    $multi_graph_output .=  "multigraph redis_per_sec\n";
    $multi_graph_output .=  "requests.value ". $total_commands_processed ."\n";
    $multi_graph_output .=  "connections.value ". $total_connections_received ."\n";
    $multi_graph_output .=  "multigraph redis_repl_backlog_size\n";
    $multi_graph_output .=  "repl_backlog_size.value " . $repl_backlog_size . "\n";

    $multi_graph_output .=  "multigraph redis_repl_lag\n";
    $multi_graph_output .=  "repl_backlog_size.value " . $repl_backlog_size  . "\n";


    $multi_graph_output .=  "multigraph redis_used_memory\n";
    $multi_graph_output .=  "used_memory.value ". $used_memory  ."\n";

    $multi_graph_output .=  "used_memory_rss.value ". $used_memory_rss  ."\n";
    $multi_graph_output .=  "used_memory_peak.value ". $used_memory_peak  ."\n";

    $multi_graph_output .=  "multigraph redis_used_keys\n";
    $multi_graph_output .=  "total_keys.value $total_keys\n";
    $multi_graph_output .=  "total_expires.value $total_expires\n";

}
print $multi_graph_output;
print $instance_graph_output;

sub get_conn {

    my $sock;

    if(-S $HOST ){

        $sock = IO::Socket::UNIX->new(
            Type => SOCK_STREAM(),
            Peer => $HOST,
        );
    }else{

        $sock = IO::Socket::INET->new(
            PeerAddr => $HOST,
            PeerPort => $PORT,
            Timeout => 10,
            Proto => 'tcp'
        );
    }

	if (! defined($sock)) {
         die "can't read socket: $!";
	}

    if ( defined( $PASSWORD )  ) {
        print $sock "AUTH ", $PASSWORD, "\r\n";
        my $result = <$sock> || die "can't read socket: $!";
    }

    return $sock;
}

sub get_info{
    my $sock = $_[0];
    print $sock "INFO\r\n";
    my $result = <$sock> || die "can't read socket: $!";

    my $rep;
    # +2 characters for \r\n at end of the data block
    read($sock, $rep, substr($result,1)+2) || die "can't read from socket: $!";

    my $hash;
    foreach (split(/\r\n/, substr($rep, 0, -2))) {
        my ($key,$val) = split(/:/, $_, 2);
        if (defined($key)) {
            $hash->{$key} = $val;
        }
    }
    return $hash;
}

# This subroutine returns configuration matched to supplied as object
sub get_config{
    my $sock = $_[1];
    print $sock "*3\r\n\$6\r\nCONFIG\r\n\$3\r\nGET\r\n\$".length($_[0])."\r\n".$_[0]."\r\n";
    # Response will look like like
    # *2\r\n$9\r\nmaxmemory\r\n$10\r\n3221225472\r\n

    my $type = <$sock> || die "can't read socket: $!";
    my $conf;
    if( substr($type,0,1) ne "*" ) {
        return $conf;
    }

    my $count=substr($type,1);

    my ( $namesize, $name, $valuesize, $value );
    while ( $count > 1 ){
        $count=$count-2;

        $namesize=<$sock>;
        read($sock, $name, substr($namesize,1)+2) || die "can't read from socket: $!";

        $valuesize=<$sock>;
        read($sock, $value, substr($valuesize,1)+2) || die "can't read from socket: $!";

        $conf->{substr($name, 0, -2)}=substr($value, 0, -2);
    }

    return $conf;
}

# vim: ft=perl ai ts=4 sw=4 et: