#!/usr/bin/perl -w
# Plugin for monitor oracle connections.
#
# Licenced under GPL v2.
#
# Usage:
#
#       Symlink into /etc/munin/plugins/ and add the monitored
#       database to the filename. e.g.:
#
#       ln -s /usr/share/munin/plugins/oracle__connections \
#         /etc/munin/plugins/oracle_<databasename>_connections
#       This should, however, be given through autoconf and suggest.
#
#       If required, give username, password and/or oracle server
#       host through environment variables.
#
#
# Parameters:
#	autoconf
#       config   (required)
#
# Config variables:
#
#       dbhost     - Which database server to use. Defaults to
#                    'localhost'.
#       dbname     - Which database to use. Defaults to orcl
#       dbuser     - A oracle user account with read permission to
#                    the v$session view. Defaults to
#                    'oracle'. Anyway, Munin must be told which user
#                    this plugin should be run as.
#       dbpass     - The corresponding password, if
#                    applicable. Default to undef.
#
#	showusers  - If set to 1 show usernames and num. of connections.
#		     Default is not show users (0).
# Magic markers
#%# family=auto
#%# capabilities=autoconf

use strict;
use DBI;

my $dbhost = $ENV{'dbhost'} || '127.0.0.1';
my $dbname = $ENV{'dbname'} || 'orcl';
my $dbuser = $ENV{'dbuser'} || 'oracle';
my $dbport = $ENV{'dbport'} || '1521';
my $dbpass = $ENV{'dbpass'} || '';
my $showusers = $ENV{'showusers'} || '0';

# Check for DBD::Oracle
if (! eval "require DBD::Oracle;") {
     exit 1;
}

my $dsn = "DBI:Oracle:dbname=$dbname;host=$dbhost;port=$dbport;sid=$dbname";
#print "$dsn\n";
my $dbh = DBI->connect ($dsn, $dbuser,
			$dbpass,
			{RaiseError =>1}) || die "";



if (exists $ARGV[0]) {
    if ($ARGV[0] eq 'autoconf') {
	# Check for DBD::Oracle
	if (! eval "require DBD::Oracle;") {
	     print "no (DBD::Oracle not found)";
	     exit 1;
	}
        if ($dbh) {
            print "yes\n";
            exit 0;
        } else {
            print "no Unable to access Database $dbname on host $dbhost as user $dbuser.\nError returned was: ". $DBI::errstr;
            exit 1;
	}
    }

    if ($ARGV[0] eq "config") {
        my $sql_max = "select value from v\$parameter where name = 'sessions'";
        my $sth_max = $dbh->prepare($sql_max);
        $sth_max->execute();
        my ($max_connections) = $sth_max->fetchrow();
        my $warning = int ($max_connections * 0.7);
        my $critical = int ($max_connections * 0.8);
        print "graph_title Oracle active connections from $dbname\n";
        print "graph_args -l 0 --base 1000\n";
        print "graph_vlabel Connections\n";
        print "graph_category db\n";
        print "graph_info Shows active oracle connections from $dbname\n";
        print "graph_scale no\n";
	if ( $showusers ) {
		my $sql = "select username, count(username) from v\$session where username  is not null group by username";
		my $sth = $dbh->prepare($sql);
		$sth->execute();
		my $setarea = "yes";
		while ( my ($datname,$curr_conn) = $sth->fetchrow_array ) {
	       		print "$datname.label $datname active connections\n";
       			print "$datname.info $datname active connections\n";
        		print "$datname.type GAUGE\n";
			if ($setarea eq "yes") {
        			print "$datname.draw AREA\n";
				$setarea="";
        		} else {
				print "$datname.draw STACK\n";
			}
		}
	} else {
	       	print "connections.label active connections\n";
       		print "connections.info active connections\n";
        	print "connections.type GAUGE\n";
        	print "connections.warning $warning\n";
        	print "connections.critical $critical\n";
	}
	print "total.label active connections\n";
       	print "total.info active connections\n";
        print "total.type GAUGE\n";
        print "total.warning $warning\n";
        print "total.critical $critical\n";
        print "max_connections.label Max. connections\n";
        print "max_connections.info Max. connections\n";
        print "max_connections.type GAUGE\n";
	exit 0;
    }
}


my $sql_max = "select value from v\$parameter where name = 'sessions'";
my $sth_max = $dbh->prepare($sql_max);
$sth_max->execute();
my ($max_connections) = $sth_max->fetchrow();

if ( $showusers ) {
	my $sql = "select username, count(username) from v\$session where username  is not null group by username";
	my $sth = $dbh->prepare($sql);
	$sth->execute();
	my $total = 0;
	while ( my ($datname,$curr_conn) = $sth->fetchrow_array ) {
		print "$datname.value $curr_conn\n";
		$total = $total+$curr_conn;
	}
	print "total.value $total\n";
} else {
	my $sql = "select count(username) from v\$session where username  is not null";
	my $sth = $dbh->prepare($sql);
	$sth->execute();
	my ($curr_conn) = $sth->fetchrow_array;
	print "connections.value $curr_conn\n";
}

print "max_connections.value $max_connections\n";