#!/usr/bin/perl

# (Temporary) source: http://munin.projects.linpro.no/ticket/63
# Written by Bjørn Ruberg (bjorn@linpro.no) 2006
# Rewritten by Moses Moore 2006-04-08  moc.iazom@sesom
# Licenced under GPL

# Magic markers
#%# family=auto
#%# capabilities=autoconf suggest

use strict;
use DBI;
use vars qw ( $debug $suggest $configure $dbh );

# Package maintainers should provide an environment
# file for the /etc/munin/plugin-conf.d/ directory
# to override these values if necessary.
# NOTE: The plugin (also when auto configured) should
# be run by the postgresql user account.

# Need these variables at an early stage to enable
# autoconf and suggest
my $dbhost = $ENV{'dbhost'} || ''; # Connect to localhost by default
my $dbname = $ENV{'dbname'} || 'template1';
my $dbuser = $ENV{'dbuser'} || 'postgres';
my $dbpass = $ENV{'dbpass'} || '';

if (exists $ARGV[0]) {
    if ($ARGV[0] eq 'autoconf') {
        # Check for DBD::Pg
        if (! eval "require DBD::Pg;") {
            print "no (DBD::Pg not found)";
            exit 0;
        }
        # Then we try to detect Postgres presence by connecting to
        # 'template1'.
        my $dsn = "dbi:Pg:dbname=template1";
        $dsn .= ";host=$dbhost" if $dbhost;
        my $tempdbh = DBI->connect ($dsn, $dbuser, $dbpass);
        if ($tempdbh) {
            print "yes\n";
            exit 0;
        } else {
            print "no (Can't connect to given host, please check environment settings)\n";
            exit 0;
        }
    } elsif ($ARGV[0] and $ARGV[0] eq 'debug') {
        # Set config flag
        $debug = 1;
    } elsif ($ARGV[0] and $ARGV[0] eq 'config') {
        # Set config flag
        $configure = 1;
    } elsif ($ARGV[0] eq 'suggest') {
        # doesn't always work
        my @datasources = DBI->data_sources ('Pg');
        foreach my $dsn (grep !/\=template\d$/, @datasources) {
            (my $db = $dsn) =~ s/^.*=//;
            print "$db\n";
        }
        exit 0;
    }
}

# Must do this here, after checking for autoconf/suggest/etc, because the
# plugin must be able to run before it is linked to the databases.
my (undef, undef, $dbname) = split (/_/, $0, 3);
die "No dbname configured (did you make the proper symlink?)" unless $dbname;

my $dsn = "DBI:Pg:dbname=$dbname";
$dsn .= ";host=$dbhost" if $dbhost;
print "#$dsn\n" if $debug;
my $dbh = DBI->connect ($dsn, $dbuser, $dbpass, {RaiseError =>1});
unless($dbh) {
    die("Database $dbname\@$dbhost (". $DBI::errstr .")\n");
}

if ($configure) {
    print <<_EOM;
graph_title Postgres database $dbname
graph_args -l 0 --base 1024
graph_vlabel bytes
graph_category db
graph_info Size
size.label Database size (bytes)
size.info Database size
size.type GAUGE
size.draw AREA
indexsize.label Index size (bytes)
indexsize.info Index size
indexsize.type GAUGE
indexsize.draw STACK
metasize.label Meta database size (bytes)
metasize.info Meta database size
metasize.type GAUGE
metasize.draw STACK
metaindexsize.label Meta index size (bytes)
metaindexsize.info Meta index size
metaindexsize.type GAUGE
metaindexsize.draw STACK
_EOM
} else {
    my $database_pages = 0;
    my $database_indexes = 0;
    my $metadatabase_pages = 0;
    my $metadatabase_indexes = 0;
    my @names = $dbh->tables;

    # Find relfilenode and relpages from the given table
    my $q_ind = "SELECT relkind, relfilenode, relpages FROM pg_class
                     WHERE relname = ?
                     UNION
                     SELECT relkind, relfilenode, relpages FROM pg_class
                     WHERE relfilenode IN (SELECT indexrelid FROM pg_index
                     WHERE indrelid IN (SELECT relfilenode FROM pg_class
                     WHERE relname = ?))";
    my $sth = $dbh->prepare ($q_ind) or die $dbh->errstr;

    # Iterate over the tables in the database
    foreach my $table (@names) {
        my $meta = 1;
        print "#TABLE: $table\n" if $debug;
        my $table_pages = 0;
        my $table_indexes = 0;
        my $metatable_pages = 0;
        my $metatable_indexes = 0;
        # "public" tables are the user data
        $meta = 0 if $table =~ /^public\./;
        $table =~ s/^.*\.//;

        # Call the query with $table twice for each side of the UNION
        $sth->execute ($table, $table) or die $dbh->errstr;
        while (my ($relkind, $relfilenode, $relpages) = $sth->fetchrow_array) {
            if ($relkind eq 'r') {
                $table_pages     += $relpages if $meta == 0;
                $metatable_pages += $relpages if $meta == 1;
            } elsif ($relkind eq 'i') {
                $table_indexes     += $relpages if $meta == 0;
                $metatable_indexes += $relpages if $meta == 1;
            }
            # Define the query
            my $q2 = "SELECT SUM(relpages)
                      FROM pg_class
                      WHERE relname IN (?, ?)";
            my $sth2 = $dbh->prepare ($q2);
            $sth2->execute ("pg_toast_${relfilenode}",
                            "pg_toast_${relfilenode}_index");
            my $relpages = $sth2->fetchrow_array;
            if ($relkind eq 'r') {
                $table_pages     += $relpages if $meta == 0;
                $metatable_pages += $relpages if $meta == 1;
            } elsif ($relkind eq 'i') {
                $table_indexes     += $relpages if $meta == 0;
                $metatable_indexes += $relpages if $meta == 1;
            }
            print "#\tR:$relfilenode\tP:$table_pages\tI:$table_indexes\n" if $debug;
        }
        $database_pages       += $table_pages;
        $database_indexes     += $table_indexes;
        $metadatabase_pages   += $metatable_pages;
        $metadatabase_indexes += $metatable_indexes;
    }
    $sth->finish;
    $dbh->disconnect;
    print "size\.value " . $database_pages * 8192 . "\n";
    print "indexsize\.value " . $database_indexes * 8192 . "\n";
    print "metasize\.value " . $metadatabase_pages * 8192 . "\n";
    print "metaindexsize\.value " . $metadatabase_indexes * 8192 . "\n";
}