#!/bin/bash
#
# MySQL and InnoDB engine Monitoring
#

service_name="mysql_monitor"

if /usr/bin/pgrep -x pdns_recursor > /dev/null; then
  echo "${service_name} - MySQL not expected"
  exit 0
fi

if [ -f /sbin/plesk ]; then
  ISPLESK=1
fi

if [ -f /root/.my.cnf ]; then
  MYSQLCMD="mysql --defaults-extra-file=/root/.my.cnf"
else
  MYSQLCMD="mysql"
fi

_innodb_check() {
  if [[ ! $ISPLESK == 1 ]]; then
    if echo show engines|$MYSQLCMD |grep -q "InnoDB.*YES";then
      if $MYSQLCMD -e "SHOW VARIABLES LIKE 'innodb_force_recovery'" |grep -q "0$"; then
        echo "${service_name} - MySQL is up and InnoDB is loaded"
        exit 0
      else
        echo "${service_name} - MySQL is up and InnoDB is loaded, but in force recovery, please check!"
        exit 2
      fi
    else
      echo "${service_name} - MySQL is up but InnoDB is NOT loaded"
      exit 2
    fi
  else
    if MYSQL_PWD=`cat /etc/psa/.psa.shadow` mysql -u admin -e "show engines" | grep -q "InnoDB.*YES";then
      echo "${service_name} - MySQL is up and InnoDB is loaded"
      exit 0
    else
      echo "${service_name} - MySQL is up but InnoDB is NOT loaded"
      exit 2
    fi
  fi
}

_mysql_check() {
  mysql_safe_count=$(pgrep mysqld_safe |wc -l)
  mysqld_count=$(pgrep 'mysqld$' |wc -l)
  if (( $mysql_safe_count > 1 )) || (( $mysqld_count > 1 )); then
    echo "[check_mk] MySQL running multiple instances" >> /var/log/mysql.error.log
    echo "${service_name} - Too many MySQL instances running, please check."
    exit 2
  elif (( $mysql_safe_count == 1 )) || (( $mysqld_count == 1 )); then
    if [[ ! $ISPLESK ]]; then
      if [ -e /tmp/mysql.sock ]; then
        echo "[check_mk] MySQL appears to be stuck" >> /var/log/mysql.error.log
        echo "${service_name} - MySQL seems stuck and needs investigated."
        exit 2
      else
        echo "${service_name} - MySQL is in crash recovery."
        exit 2
      fi
    fi
  else
    echo "[check_mk] MySQL is 'not running'" >> /var/log/mysql.error.log
    echo "${service_name} - MySQL is not running, please check."
    exit 2
  fi
}

if [[ ! $ISPLESK == 1 ]]; then #&& ! mysql --defaults-file=/root/.my.cnf -e ';' --connect_timeout=10 &> /dev/null;then
  if [[ -e "/root/.my.cnf" ]]; then
    if ! mysql --defaults-file=/root/.my.cnf -e ';' --connect_timeout=10 &> /dev/null;then
      _mysql_check
    else
      _innodb_check
    fi
  else
    _innodb_check
  fi
elif [[ $ISPLESK == 1 ]]; then
  if ! MYSQL_PWD=`cat /etc/psa/.psa.shadow` mysql -u admin -e ';' --connect_timeout=10 &> /dev/null;then
    echo "${service_name} - MySQL is not responding, please check."
    exit 2
  else
    _innodb_check
  fi
else
  _innodb_check
fi