=head1 NAME

B<check_mysql> - spong-network module to check MySQL servers

=head1 DESCRIPTION

This is a plugin module for the Spong L<spong-network> program.  The
B<check_mysql> module checks the status of MySQL servers by querying
them using the mysqladmin command.

It not only alerts you to a problem if it can't connect, but it also
returns some potentially interesting numbers.  These numbers can be
graphed using L<spong-rrd>.

=cut

# Register the routine with the plugin registry
$PLUGINS{'mysql'} = \&check_mysql;

sub check_mysql {
   my( $host ) = @_;
   my( $dbuser ) = $HOSTS{$host}{'mysql'}{'dbuser'}
                   || $HOSTS_DEFAULTS{'mysql'}{'dbuser'};
   my( $dbpass ) = $HOSTS{$host}{'mysql'}{'dbpass'}
                   || $HOSTS_DEFAULTS{'mysql'}{'dbpass'};
   my( $color, $summary, $message ) = ( "green", "MySQL Ok", "" );

   open (MYSQL,"$MYSQLADMIN $host status -u$dbuser -p$dbpass 2>&1 |") || warn "Could not exec $MYSQLADMIN for status info.";
   while (<MYSQL>) {
      $message .= $_;
      if (/Can\'t connect/) {
         $color = "red"; $summary = "Server is unreachable.";
      }
      if (/Access denied/) {
             $color = "yellow"; $summary = "Server is up, but access is denied.";
      }
   }
  
   &debug( "mysql - $host - $color, $summary" );
   return( $color, $summary, $message );
}

1;

__END__

=head2 Output Returned

=over 4

=item Status

If there is nothing degraded or failed on the MySQL server then 'green'
status is returned.  Otherwise 'yellow' is returned if we don't have access
or 'red' is returned if the connection fails.

This could be extended in the future to check and see if a minimum number
of tables are present.

=item Summary Field

If there are no problems, 'MySQL Ok' is returned. Otherwise the summary field
will have a short description of what the problem or anamoly is.

=item Detail Message Field

If the MySQL process is contactable, then the detail message will have
some interesting numbers from the MySQL server.

=back

=head2 Configuration

It is necessary to add the following to L<spong.conf>:

$MYSQLADMIN = "/usr/bin/mysqladmin -h";

Where C</usr/bin> is replaced with the path that leads to C<mysqladmin>.

It is possible to set configuration details both for as a a default and
then for specific hosts.  An example is given in L<EXAMPLES>.

=back

=head1 EXAMPLES

 %HOSTS_DEFAULTS = (
   'mysql' => {
     'dbuser' => 'spong',
     'dbpass' => 'default-password'
   }
 )

 %HOSTS = (
   'mysql.server.com' => {
     'services' => 'mysql',
     'mysql'    => {
       'dbpass' => 'host-specific-password'
     }
   }

=head1 SEE ALSO

L<spong-network>, L<check_insight>,
L<spong-network Modules Template|spong-network-mod-template>,
L<Spong Developer's Guide|developer-guide>

=head1 RESTRICTIONS

B<check_mysql> uses mysqladmin, hence it is necessary to have some basic
client utilities installed from MySQL.

=head1 AUTHOR

Miles Lott <milos@insync.net>

Support for %HOSTS and %HOSTS_DEFAULTS and POD documentation added by
Andrew Ruthven <andrew@etc.gen.nz> - 2002/06/13.