check_instance_up

#! /usr/bin/env bash

###############################################################################
# Monitor DB2 with Nagios
# Copyright 2013,2014,2015 Andres Gomez Casanova
# https://github.com/angoca/monitor-db2-with-nagios
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
###############################################################################

# This script queries the status of the instance by retrieving the port number
# or service name from the configuration, and then querying netstat to check if
# there is an associated service with that port.
#
# It is necessary to execute this script with a user with at least SYSMON
# authority, in order to retrieve all the necessary information. If not, the
# script will produce a critical alert indicating that the PID of the instance
# cannot be retrieved.
#
# This script was based on the plugins written by Felipe Alkain de Souza.
# http://www.dbatodba.com/db2/scripts-db2/nagios-plugins
#
# In order to be used in Nagios, you have to configure the following.
#
# # 'check_instance_up' command definition
# define command {
#         command_name    check_instance_up
#         command_line    $USER1$/check_by_ssh -H $HOSTADDRESS$ -l nagios -C "scripts/check_instance_up -i '$ARG1$'"
# }
# define service{
#         host_name               db2server
#         service_description     Instance status
#         check_command           check_instance_up!/home/db2inst1
#         use                     generic-service
# }
#
# When using NRPE:
#
# In the database server:
#
# command[check_instance_up]=/home/nagios/scripts/check_instance_up -i /home/db2inst1
#
# Then modify the path according to your script location and instance home dir.
#
# In the Nagios server:
#
# define service{
#         host_name               db2server
#         service_description     Instance status
#         check_command           check_nrpe_1arg!check_instance_up
#         use                     generic-service
# }
#
# It is necessary to execute this script with a user with at least SYSMON authority, in
# order to execute db2pd.
#
# Parameters:
# -h | --help : Show the help of this script.
# -i | --instance : Home directory of the instance. Usually it is
#   /home/db2inst1.
# -K | --mk : Change the output for Check_MK.
# -T | --trace : Trace mode. Writes output in /tmp.
# -v | --verbose : Execute the program in verbose mode.
# -V | --version : Show the current version of this script.
#
# In AIX, the long name options are not supported.
#
# The exit codes are the standard for Nagios.
#
# 0 The plugin was able to check the service and it appeared to be functioning
#   properly.
# 1 The plugin was able to check the service, but it appeared to be above some
#   "warning" threshold or did not appear to be working properly.
# 2 The plugin detected that either the service was not running or it was above
#   some "critical" threshold.
# 3 Invalid command line arguments were supplied to the plugin or low-level
#   failures internal to the plugin (such as unable to fork, or open a tcp
#   socket) that prevent it from performing the specified operation.
#   Higher-level errors (such as name resolution errors, socket timeouts, etc)
#   are outside of the control of plugins and should generally NOT be reported
#   as UNKNOWN states.
#
# Author: Andres Gomez Casanova
# Version: v1.1 2015-10-15

# Flag for debugging.
#set -xv

# Locale to print messages in English. Prevent language problems.
export LANG=en_US

# Version of this script.
function print_revision {
  echo Andres Gomez Casanova - AngocA
  echo v1.1 2015-10-15
}
# Function to show the help
function print_usage {
  /bin/cat <<__EOT
Usage: ${1} { -i instanceHomeDirectory [-K]| -h | -V }[-T][-v]"
__EOT
}

function print_help {
  print_revision
  print_usage ${1}
  # Max 80 chars width.
  /bin/cat <<__EOT
-------------------------------------------------------------------------------
This script checks if the instance is active by querying netstats.
-h | --help
   Shows the current documentation.
-i | --instance STRING
   Instance home directory. It is usually /home/db2inst1.
-K | --mk
   Changes the output to be compatible with Check_MK.
-T | --trace
   Trace mode: writes date and output in /tmp.
-v | --verbose
   Executes the script in verbose mode (multiple times).
-V | --version
   Shows the current version of this script.

In AIX, the long name options are not supported.
__EOT
}

# Variable to control the flow execution. Prevent Spaghetti code.
CONTINUE=true

# Nagios return codes
OK=0
WARNING=1
CRITICAL=2
UNKNOWN=3
# This is the returned code.
RETURN=${UNKNOWN}

# Nagios Output
# Text output 80 chars | Optional Perf Data Line 1
# Long text Line 1
# Long text Line 2 | Optional Perf Data Line 2
# Optional Perf Data Line 3
OUTPUT=
PERFORMANCE=
LONG_OUTPUT=
LONG_PERFORMANCE=
PERF_MK="-"

APPL_NAME=$(basename ${0})

echo "$(date +"%Y-%m-%d-%H.%M.%S") $$ Started ${APPL_NAME} $@" >> /tmp/${APPL_NAME}.log

# Checks the lock file does not exist.
# The lock file is the way the command was called with its parameters
# without spaces.
COPY_ARGS=("${@}") 
LOCK_FILE=
for VALUE in "${COPY_ARGS[@]}" ; do
  LOCK_FILE="${LOCK_FILE}${VALUE}"
done
LOCK_FILE=${LOCK_FILE//\//}
LOCK_FILE=${LOCK_FILE//\\/}
LOCK_FILE=${LOCK_FILE//\:/}
LOCK_FILE=${LOCK_FILE//\*/}
LOCK_FILE=${LOCK_FILE//\|/}
LOCK_FILE="/tmp/${APPL_NAME}${LOCK_FILE}.lock"
if [[ ! -r ${LOCK_FILE} ]] ; then
  echo $$ > ${LOCK_FILE}
  LOCKED=true
else
  # If it exist, then check if the process is running.
  EXIST=$(ps -ef | grep $(cat ${LOCK_FILE}) | grep ${APPL_NAME})
  # If process is not running, delete it.
  if [[ ${EXIST} == "" ]] ; then
    rm ${LOCK_FILE}
    if [[ ! -r ${LOCK_FILE} ]] ; then
      echo $$ > ${LOCK_FILE}
      LOCKED=true
    else
      OUTPUT="The lock file cannot be replaced: ${LOCK_FILE}"
      CONTINUE=false
      RETURN=${UNKNOWN}
    fi
  else
    OUTPUT="An instance of the script with the same parameters is already running."
    CONTINUE=false
    RETURN=${UNKNOWN}
  fi
fi

if [[ ${#} -eq 0 ]] ; then
  print_usage ${APPL_NAME}
  RETURN=${UNKNOWN}
  CONTINUE=false
fi

# Checks the operating system. geopt works different in AIX than in Linux.
OS=$(uname)

if [[ "${OS:0:5}" == "Linux" ]] ; then
  # The following requires GNU getopt. See the following discussion.
  # http://stackoverflow.com/questions/402377

  TEMP=$(getopt -o hi:KTvV --long help,instance:,mk,trace,verbose,version \
               -n ${APPL_NAME} -- "${@}")
elif [[ "${OS:0:3}" == "AIX" ]] ; then
  set -- $(getopt hi:KTvV ${*})
elif [[ "${OS:0:6}" == "Darwin" || "${OS:0:5}" == "SunOS" || "${OS:0:5}" == "HP-UX" ]] ; then
  echo "This plugin is not yet supported in your platform."
  echo "Please create a ticket in GitHub if you want to enable your current platform."
  echo "https://github.com/angoca/monitor-db2-with-nagios/issues"
  RETURN=${UNKNOWN}
  CONTINUE=false
elif [[ "${OS:0:6}" == "CYGWIN" ]] ; then
  echo "This plugin is not supported in Cygwin"
  RETURN=${UNKNOWN}
  CONTINUE=false
else
  echo "The platform is unknown: ${OS}"
  echo "Please create a ticket in GitHub: https://github.com/angoca/monitor-db2-with-nagios/issues"
  RETURN=${UNKNOWN}
  CONTINUE=false
fi

if [[ ${?} -ne 0 ]] ; then
  print_usage ${APPL_NAME}
  RETURN=${UNKNOWN}
  CONTINUE=false
fi

if [[ ${CONTINUE} == true ]] ; then
  if [[ "${OS}" == "Linux" ]] ; then
    # Note the quotes around ${TEMP}: they are essential!
    eval set -- "${TEMP}"
  fi
  HELP=false
  VERSION=false
  CHECK_MK=false
  # Verbosity level
  VERBOSE=0
  # Trace activated
  TRACE=false
  LOG=/tmp/${APPL_NAME}.log
  INSTANCE_HOME=
  if [[ "${OS:0:5}" == "Linux" ]] ; then
    while true; do
      case "${1}" in
        -h | --help ) HELP=true ; shift ;;
        -i | --instance ) INSTANCE_HOME=$(echo ${2} | cut -d' ' -f1) ; shift 2 ;;
        -K | --mk ) CHECK_MK=true ; shift ;;
        -T | --trace ) TRACE=true ; shift ;;
        -v | --verbose ) VERBOSE=$(( ${VERBOSE} + 1 )) ; shift ;;
        -V | --version ) VERSION=true ; shift ;;
        -- ) shift ; break ;;
        * ) break ;;
      esac
    done
  elif [[ "${OS:0:3}" = "AIX" ]] ; then
    while [[ $1 != -- ]] ; do
      case "${1}" in
        -h) HELP=true ; shift ;;
        -i) INSTANCE_HOME=$(echo ${2} | cut -d' ' -f1) ; shift 2 ;;
        -K) CHECK_MK=true ; shift ;;
        -T) TRACE=true ; shift ;;
        -v) VERBOSE=$(( ${VERBOSE} + 1 )) ; shift ;;
        -V) VERSION=true ; shift ;;
        * ) break ;;
      esac
    done
  fi
fi

if [[ ${TRACE} == true ]] ; then
  echo ">>>>>" >> ${LOG}
  date >> ${LOG}
  echo "Instance at ${INSTANCE_HOME}" >> ${LOG}
  echo "PID ${$}" >> ${LOG}
fi

ECHO="help:${HELP}, version:${VERSION}, verbose:${VERBOSE}"
ECHO="${ECHO}, directory:${INSTANCE_HOME}"
ECHO="${ECHO}, check_mk:${CHECK_MK}"

if [[ ${VERBOSE} -ge 2 ]] ; then
  echo ${ECHO}
fi

if [[ ${TRACE} == true ]] ; then
  echo "PARAMS:${ECHO}" >> ${LOG}
fi

if [[ ${CONTINUE} == true && ${HELP} == true ]] ; then
  print_help ${APPL_NAME}
  RETURN=${UNKNOWN}
  CONTINUE=false
fi

if [[ ${CONTINUE} == true && ${VERSION} == true ]] ; then
  print_revision ${APPL_NAME}
  RETURN=${UNKNOWN}
  CONTINUE=false
fi

if [[ ${CONTINUE} == true && ${INSTANCE_HOME} == "" ]] ; then
  print_usage ${APPL_NAME}
  RETURN=${UNKNOWN}
  CONTINUE=false
fi

if [[ ${CONTINUE} == true ]] ; then
  # Trims the characters.
  INSTANCE_HOME=$(echo ${INSTANCE_HOME} | cut -d' ' -f1)
  if [[ -d ${INSTANCE_HOME} && -e ${INSTANCE_HOME}/sqllib/db2profile ]] ; then
    # Load the DB2 profile.
    . ${INSTANCE_HOME}/sqllib/db2profile
    INSTANCE_NAME=$(db2 get instance | awk '/instance/ {print $7}')
  else
    OUTPUT="Instance directory is invalid."
    RETURN=${UNKNOWN}
    CONTINUE=false
  fi
fi

if [[ ${CONTINUE} == true ]] ; then
  COMMAND_PID="db2pd -edus"
  if [[ ${VERBOSE} -ge 2 ]] ; then
    echo "COMMAND: ${COMMAND_PID}"
  fi
  OUTPUT_PID=$(${COMMAND_PID} | grep 'db2sysc PID' | cut -d' ' -f3)
  if [[ ${VERBOSE} -ge 3 ]] ; then
    echo "Result: ${OUTPUT_PID}"
  fi

  COMMAND_CONF="db2 get dbm cfg"
  if [[ ${VERBOSE} -ge 2 ]] ; then
    echo "COMMAND: ${COMMAND_CONF}"
  fi
  OUTPUT_CONF=$(${COMMAND_CONF})
  # Gets the service name configure in the instance. It could be a text or a number.
  SVCNAME=$(printf '%s\n' "${OUTPUT_CONF}" | grep SVCENAME | cut -d= -f2 | sed "s/^[ \t]*//")
  # Copies the value in portnum, but checks later.
  PORTNUM=${SVCNAME}

  if ! [[ ${SVCNAME} =~ ^[0-9]+$ ]] ; then
    # SVCNAME is a text, thus replace portnum.
    REGEXP="^${SVCNAME}\s"
    PORTNUM=$(grep -P ${REGEXP} /etc/services | awk '{print $2}' | cut -d/ -f1)
  fi

  MAX_DB=$(printf '%s\n' "${OUTPUT_CONF}" | awk '/NUMDB/ {print $9}')
  if [[ ${VERBOSE} -ge 3 ]] ; then
    echo "Result: ${MAX_DB}"
  fi

  # Checks if the port has a active service associated.
  if [[ ${PORTNUM} != "" ]] ; then
    if [[ ${VERBOSE} -ge 2 ]] ; then
      echo "COMMAND: netstat -na | grep ${PORTNUM} | wc -l"
    fi
    PROC=$(netstat -na | grep ${PORTNUM} | wc -l)
	PROC=$(echo ${PROC})
    if [[ ${VERBOSE} -ge 3 ]] ; then
      echo "Result: ${PROC}"
    fi
  fi

  if [[ ${OUTPUT_PID} == "" || ! ${OUTPUT_PID} =~ ^[0-9]+$ ]] ; then
    OUTPUT="Instance is not started (not listed in EDUs). "
    PERFORMANCE="'Started_Instance'=0.1;;0.4"
    RETURN=${UNKNOWN}
  else
    OUTPUT="PID: ${OUTPUT_PID}. "
  fi
  if [[ ${SVCNAME} == "" ]] ; then
    OUTPUT="${OUTPUT}TCP port not defined or instance output is invalid."
    PERFORMANCE="'Started_Instance'=0.1;;0.4"
    RETURN=${CRITICAL}
  elif [[ ${PORTNUM} == "" || ! ${PORTNUM} =~ ^[0-9]+$ ]] ; then
    OUTPUT="${OUTPUT}Problem retrieving port number."
    PERFORMANCE="'Started_Instance'=0.2;;0.4"
    RETURN=${CRITICAL}
  elif [[ ! ${PROC} =~ ^[0-9]+$ ]] ; then
    OUTPUT="${OUTPUT}Weird situation."
    PERFORMANCE="'Started_Instance'=0.0;;0.4"
    RETURN=${UNKNOWN}
  else
    if [[ ${PROC} -eq "0" ]] ; then
      OUTPUT="Instance at ${INSTANCE_HOME} is down."
      PERFORMANCE="'Started_Instance'=0.3;;0.4"
      RETURN=${CRITICAL}
    elif [[ ! ${OUTPUT_PID} =~ ^[0-9]+$ ]] ; then
      OUTPUT="Instance at ${INSTANCE_HOME} is up but the PID is unknown"
      PERFORMANCE="'Started_Instance'=${MAX_DB};;0.4"
      RETURN=${WARNING}
    else
      OUTPUT="Instance at ${INSTANCE_HOME} is up (PID ${OUTPUT_PID})."
      PERFORMANCE="'Started_Instance'=${MAX_DB};;0.4"
      RETURN=${OK}
    fi
  fi

  COMMAND_ACTIVE="db2 list active databases"
  if [[ ${VERBOSE} -ge 2 ]] ; then
    echo "Command: ${COMMAND_ACTIVE}"
  fi

  ACTIVE=$(${COMMAND_ACTIVE} | grep 'Database name' | wc -l)
  if [[ ${VERBOSE} -ge 2 ]] ; then
    echo "Result: ${ACTIVE}"
  fi

  LONG_OUTPUT="There are $(echo ${ACTIVE}) active databases"
  LONG_PERFORMANCE="'Active_Databases'=$(echo ${ACTIVE})"
  PERF_MK="${PERFORMANCE}|${LONG_PERFORMANCE}"
fi

# Prints the output.
if [[ ${OUTPUT} == "" ]] ; then
  OUTPUT="Note: The test was not executed."
fi
# Builds the output.
if [[ ${CHECK_MK} == true ]] ; then
  echo "${RETURN} instanceUp-${INSTANCE_NAME} ${PERF_MK} ${OUTPUT}"
else
  echo -e "${OUTPUT}|${PERFORMANCE}\n${LONG_OUTPUT}|${LONG_PERFORMANCE}"
fi
# Returns the error code.
if [[ ${VERBOSE} -ge 2 ]] ; then
  echo "Return code: ${RETURN}"
fi
if [[ ${TRACE} == true ]] ; then
  echo -e "OUTPUT:${OUTPUT}\nPERF:${PERFORMANCE}\nLONG_OUT:${LONG_OUTPUT}\nLONGPERF:${LONG_PERFORMANCE}\nRET_CODE:${RETURN}" >> ${LOG}
  date >> ${LOG}
  echo -e "<<<<<\n" >> ${LOG}
fi

if [[ ${LOCKED} == true && -r ${LOCK_FILE} ]] ; then
  rm ${LOCK_FILE}
fi

echo "$(date +"%Y-%m-%d-%H.%M.%S") $$ Ended ${APPL_NAME} ${COPY_ARGS[@]}" >> /tmp/${APPL_NAME}.log

exit ${RETURN}