#!/bin/bash
PROGNAME=`basename $0`
VERSION="Version 1.1.3"
AUTHOR="Guillaume Coré <fridim@onfi.re>, Ales Nosek <ales.nosek@gmail.com>"

ST_OK=0
ST_WR=1
ST_CR=2
ST_UK=3

print_version() {
  echo "$VERSION $AUTHOR"
}

print_help() {
  print_version $PROGNAME $VERSION
  echo ""
  echo "$PROGNAME is a Nagios plugin to monitor Galera cluster status."
  echo ""
  echo "$PROGNAME [-u USER] [-p PASSWORD] [-H HOST] [-P PORT] [-w SIZE] [-c SIZE] [-f FLOAT] [-0]"
  echo ""
  echo "Options:"
  echo "  u)"
  echo "    MySQL user."
  echo "  p)"
  echo "    MySQL password."
  echo "  H)"
  echo "    MySQL host."
  echo "  P)"
  echo "    MySQL port."
  echo "  w)"
  echo "    Sets minimum number of nodes in the cluster when WARNING is raised. (default is same as critical)."
  echo "  c)"
  echo "    Sets minimum number of nodes in the cluster when CRITICAL is raised. (default is 2)."
  echo "  f)"
  echo "    Sets critical value of wsrep_flow_control_paused (default is 0.1)."
  echo "  0)"
  echo "    Rise CRITICAL if the node is not primary"
  exit $ST_UK
}

# default values
crit=2
fcp=0.1

check_executable() {
    if [ -z "$1" ]; then
        echo "check_executable: no parameter given!"
        exit $ST_UK
    fi

    if ! command -v "$1" &>/dev/null; then
        echo "UNKNOWN: Cannot find $1"
        exit $ST_UK
    fi
}

check_executable mysql
check_executable bc

while getopts “hvu:p:H:P:w:c:f:0” OPTION; do
  case $OPTION in
    h)
      print_help
      exit $ST_UK
      ;;
    v)
      print_version $PROGNAME $VERSION
      exit $ST_UK
      ;;
    u)
      mysqluser=$OPTARG
      ;;
    p)
      password=$OPTARG
      ;;
    H)
      mysqlhost=$OPTARG
      ;;
    P)
      port=$OPTARG
      ;;
    w)
      warn=$OPTARG
      ;;
    c)
      crit=$OPTARG
      ;;
    f)
      fcp=$OPTARG
      ;;
    0)
      primary='TRUE'
      ;;
    ?)
      echo "Unknown argument: $1"
      print_help
      exit $ST_UK
      ;;
  esac
done

if [ -z "$warn" ]; then
  warn=$crit
fi

create_param() {
  if [ -n "$2" ]; then
    echo $1$2
  fi
}

param_mysqlhost=$(create_param -h "$mysqlhost")
param_port=$(create_param -P "$port")
param_mysqluser=$(create_param -u "$mysqluser")
param_password=$(create_param -p "$password")

r1=$(mysql $param_mysqlhost $param_port $param_mysqluser $param_password -B -N -e "show status like 'wsrep_cluster_size'"|cut -f 2) # 3  (GALERA_CLUSTER_SIZE)
r2=$(mysql $param_mysqlhost $param_port $param_mysqluser $param_password -B -N -e "show status like 'wsrep_cluster_status'"|cut -f 2) # Primary
r3=$(mysql $param_mysqlhost $param_port $param_mysqluser $param_password -B -N -e "show status like 'wsrep_flow_control_paused'"|cut -f 2) # < 0.1
r4=$(mysql $param_mysqlhost $param_port $param_mysqluser $param_password -B -N -e "show status like 'wsrep_ready'"|cut -f 2)  # ON
r5=$(mysql $param_mysqlhost $param_port $param_mysqluser $param_password -B -N -e "show status like 'wsrep_connected'"|cut -f 2)  # ON
r6=$(mysql $param_mysqlhost $param_port $param_mysqluser $param_password -B -N -e "show status like 'wsrep_local_state_comment'"|cut -f 2)  # Synced

if [ -z "$r3" ]; then
  echo "UNKNOWN: wsrep_flow_control_paused is empty"
  ST_FINAL=$ST_UK
fi

if [ $(echo "$r3 > $fcp" | bc) = 1 ]; then
  echo "CRITICAL: wsrep_flow_control_paused is > $fcp"
  ST_FINAL=$ST_CR
fi

if [ "$primary" = 'TRUE' ]; then
  if [ "$r2" != 'Primary' ]; then
    echo "CRITICAL: node is not primary (wsrep_cluster_status)"
    ST_FINAL=$ST_CR
  fi
fi

if [ "$r4" != 'ON' ]; then
  echo "CRITICAL: node is not ready (wsrep_ready)"
  ST_FINAL=$ST_CR
fi

if [ "$r5" != 'ON' ]; then
  echo "CRITICAL: node is not connected (wsrep_connected)"
  ST_FINAL=$ST_CR
fi

if [ "$r6" != 'Synced' ]; then
  echo "CRITICAL: node is not synced - actual state is: $r6 (wsrep_local_state_comment)"
  ST_FINAL=$ST_CR
fi

if [ $r1 -gt $warn ]; then
  echo "OK: number of NODES = $r1 (wsrep_cluster_size)"
  ST_FINAL=${ST_FINAL-$ST_OK}
elif [ $r1 -le $crit ]; then
  echo "CRITICAL: number of NODES = $r1 (wsrep_cluster_size)"
  ST_FINAL=$ST_CR
elif [ $r1 -le $warn ]; then
  echo "WARNING: number of NODES = $r1 (wsrep_cluster_size)"
  ST_FINAL=${ST_FINAL-$ST_WR}
else
  exit $ST_UK
fi

exit $ST_FINAL