#!/bin/sh

# ########################################################################
# This program is part of $PROJECT_NAME$
# License: GPL License (see COPYING)
# Authors:
#  Baron Schwartz
# Depends-on: pt-deadlock-logger
# ########################################################################

# ########################################################################
# Redirect STDERR to STDOUT; Nagios doesn't handle STDERR.
# ########################################################################
exec 2>&1

# ########################################################################
# Set up constants, etc.
# ########################################################################
STATE_OK=0
STATE_OK=0
STATE_WARNING=1
STATE_CRITICAL=2
STATE_UNKNOWN=3
STATE_DEPENDENT=4

# ########################################################################
# Run the program.
# ########################################################################
main() {
   # Get options
   for o; do
      case "${o}" in
         -c)              shift; OPT_CRIT="${1}"; shift; ;;
         --defaults-file) shift; OPT_DEFT="${1}"; shift; ;;
         -H)              shift; OPT_HOST="${1}"; shift; ;;
         -i)              shift; OPT_INTERVAL="${1}"; shift; ;;
         -l)              shift; OPT_USER="${1}"; shift; ;;
         -L)              shift; OPT_LOPA="${1}"; shift; ;;
         -p)              shift; OPT_PASS="${1}"; shift; ;;
         -P)              shift; OPT_PORT="${1}"; shift; ;;
         -S)              shift; OPT_SOCK="${1}"; shift; ;;
         -T)              shift; OPT_TABLE="${1}";  shift; ;;
         -w)              shift; OPT_WARN="${1}"; shift; ;;
         --version)       grep -A2 '^=head1 VERSION' "$0" | tail -n1; exit 0 ;;
         --help)          perl -00 -ne 'm/^  Usage:/ && print' "$0"; exit 0 ;;
         -*)              echo "Unknown option ${o}.  Try --help."; exit 1; ;;
      esac
   done
   OPT_WARN=${OPT_WARN:-12}
   OPT_CRIT=${OPT_CRIT:-60}
   OPT_INTERVAL=${OPT_INTERVAL:-1}
   OPT_TABLE="${OPT_TABLE:-percona.deadlocks}"
   if [ -e '/etc/nagios/mysql.cnf' ]; then
      OPT_DEFT="${OPT_DEFT:-/etc/nagios/mysql.cnf}"
   fi
   if is_not_sourced; then
      if [ -n "$1" ]; then
         echo "WARN spurious command-line options: $@"
         exit 1
      fi
   fi

   LEVEL=$(mysql_exec "SELECT COUNT(*) FROM ${OPT_TABLE} WHERE server IN ('${OPT_HOST}', @@hostname) AND ts >= NOW() - INTERVAL ${OPT_INTERVAL}*60 SECOND")
   if [ $? = 0 ]; then
      NOTE="${LEVEL:-UNKNOWN} deadlocks in last ${OPT_INTERVAL} minutes"
      if [ "${LEVEL:-0}" -gt "${OPT_CRIT}" ]; then
         NOTE="CRIT $NOTE"
      elif [ "${LEVEL:-0}" -gt "${OPT_WARN}" ]; then
         NOTE="WARN $NOTE"
      else
         NOTE="OK $NOTE"
      fi

      # Build the common perf data output for graph trending
      PERFDATA="deadlocks=${LEVEL:-0};${OPT_WARN};${OPT_CRIT};0;"
      NOTE="$NOTE | $PERFDATA"
   else
      NOTE="UNK could not count deadlocks"
   fi
   echo $NOTE
}

# ########################################################################
# Execute a MySQL command.
# ########################################################################
mysql_exec() {
   mysql ${OPT_DEFT:+--defaults-file="${OPT_DEFT}"} ${OPT_HOST:+-h"${OPT_HOST}"} ${OPT_USER:+-u"${OPT_USER}"} \
      ${OPT_PASS:+-p"${OPT_PASS}"} ${OPT_SOCK:+-S"${OPT_SOCK}"} ${OPT_PORT:+-P"${OPT_PORT}"} \
      ${OPT_LOPA:+--login-path="${OPT_LOPA}"} -ss -e "$1"
}

# ########################################################################
# Determine whether this program is being executed directly, or sourced/included
# from another file.
# ########################################################################
is_not_sourced() {
   [ "${0##*/}" = "pmp-check-mysql-deadlocks" ] || [ "${0##*/}" = "bash" -a "$_" = "$0" ]
}

# ########################################################################
# Execute the program if it was not included from another file.
# This makes it possible to include without executing, and thus test.
# ########################################################################
if is_not_sourced; then
   OUTPUT=$(main "$@")
   EXITSTATUS=$STATE_UNKNOWN
   case "${OUTPUT}" in
      UNK*)  EXITSTATUS=$STATE_UNKNOWN;  ;;
      OK*)   EXITSTATUS=$STATE_OK;       ;;
      WARN*) EXITSTATUS=$STATE_WARNING;  ;;
      CRIT*) EXITSTATUS=$STATE_CRITICAL; ;;
   esac
   echo "${OUTPUT}"
   exit $EXITSTATUS
fi

# ############################################################################
# Documentation
# ############################################################################
: <<'DOCUMENTATION'
=pod

=head1 NAME

pmp-check-mysql-deadlocks - Alert when pt-deadlock-logger has recorded too many recent deadlocks.

=head1 SYNOPSIS

  Usage: pmp-check-mysql-deadlocks [OPTIONS]
  Options:
    -c CRIT         Critical threshold; default 60.
    --defaults-file FILE Only read mysql options from the given file.
                    Defaults to /etc/nagios/mysql.cnf if it exists.
    -H HOST         MySQL hostname.
    -i INTERVAL     Interval over which to count, in minutes; default 1.
    -l USER         MySQL username.
    -L LOGIN-PATH   Use login-path to access MySQL (with MySQL client 5.6).
    -p PASS         MySQL password.
    -P PORT         MySQL port.
    -S SOCKET       MySQL socket file.
    -T TABLE        The database.table that pt-deadlock-logger uses; default percona.deadlocks.
    -w WARN         Warning threshold; default 12.
    --help          Print help and exit.
    --version       Print version and exit.
  Options must be given as --option value, not --option=value or -Ovalue.
  Use perldoc to read embedded documentation with more details.

=head1 DESCRIPTION

This Nagios plugin looks at the table that pt-deadlock-logger (part of Percona
Toolkit) maintains, and when there have been too many recent deadlocks, it
alerts.

=head1 PRIVILEGES

This plugin executes the following commands against MySQL:

=over

=item *

C<SELECT> from the C<pt-deadlock-logger> table.

=back

This plugin executes no UNIX commands that may need special privileges.

=head1 COPYRIGHT, LICENSE, AND WARRANTY

This program is copyright 2012-$CURRENT_YEAR$ Baron Schwartz, 2012-$CURRENT_YEAR$ Percona Inc.
Feedback and improvements are welcome.

THIS PROGRAM IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED
WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.

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.  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.

=head1 VERSION

$PROJECT_NAME$ pmp-check-mysql-deadlocks $VERSION$

=cut

DOCUMENTATION