#!/bin/bash
#
# Plugin for monitor JVM activity - GC Time -
#
# Usage:
#
#       Symlink into /etc/munin/plugins/ and add the monitored
#	alias name like :
#
#       ln -s /usr/share/munin/plugins/jstat__gctime \
#	  /etc/munin/plugins/jstat_<jvm alias>_gctime
#       This should, however, be given through autoconf and suggest.
#
# Requirements:
#
#	You need to execute your Java program under jsvc provided by
#	  http://jakarta.apache.org/commons/daemon/
#	which enables you to run your Java program with specified
#	pid file with -pidfile option.
#       A Brief setup documentation is also available at
#         http://tomcat.apache.org/tomcat-5.5-doc/setup.html
#
# Target:
#
#	Target Java Virtual Machine to monitor are:
#	  Sun JDK 5.0 (http://java.sun.com/javase/) (default)
#	  BEA JRockit 5.0 (http://dev2dev.bea.com/jrockit/)
#
# Parameters:
#
#       config   (required)
#
# Config variables:
#
#       pidfilepath  - Which file path use. Defaults to '/var/run/jsvc.pid'
#       javahome     - override automatic detection of JRE directory
#       graphtitle   - Title of the graph (defaults to PID file location)
#

default_java_home=/usr/lib/jvm/default-java
[ -e "$default_java_home" ] || default_java_home=/usr/local/java/jdk

pidfilepath=${pidfilepath:-/var/run/jsvc.pid}
graphtitle=${graphtitle:-$pidfilepath}
JAVA_HOME=${javahome:-$default_java_home}

export JAVA_HOME

#
# Functions
#
chk_jdk()
{
  isJRockit=`${JAVA_HOME}/bin/java -version 2>&1 | egrep -i 'jrockit'`
  if [ -n "${isJRockit}" ]; then
    JDK_TYPE="bea"
  else
    JDK_TYPE="sun"
  fi
}

chk_version()
{
  Version=`${JAVA_HOME}/bin/java -version 2>&1 | egrep '^java version' | awk '{print $3}' | sed -e 's/\"//g' | cut -d'_' -f 1`
  if [ "${Version}" != "1.5.0" ]; then
    return 1
  else
    return 0
  fi
}

config_common()
{
        echo 'graph_title GC Time' $graphtitle
        echo 'graph_args -l 0'
        echo 'graph_vlabel GC Time(sec)'
        echo 'graph_total total'
        echo 'graph_info GC Time'
        echo 'graph_category virtualization'
}

config_sun_jdk()
{
  config_common

  echo 'Young_GC.label Young_GC'
  echo 'Young_GC.min 0'
  echo 'Full_GC.label Full_GC'
  echo 'Full_GC.min 0'

}

config_bea_jdk()
{
  config_common

  echo 'Young_GC.label Young_GC'
  echo 'Young_GC.min 0'
  echo 'Old_GC.label Old_GC'
  echo 'Old_GC.min 0'
  echo 'Young_Pause.label Young_GC Pause'
  echo 'Young_Pause.min 0'
  echo 'Old_Pause.label Old_GC Pause'
  echo 'Old_Pause.min 0'

}

print_sun_stats()
{
${JAVA_HOME}/bin/jstat -gc ${PidNum} | tail -1 | awk \
'{\
	S0C = $1; \
	S1C = $2; \
	S0U = $3; \
	S1U = $4; \
	EC  = $5; \
	EU  = $6; \
	OC  = $7; \
	OU  = $8; \
	PC  = $9; \
	PU  = $10; \
        YGC  = $11; \
        YGCT  = $12; \
        FGC  = $13; \
        FGCT  = $14; \
        GCT  = $15; \

	\
	S0F = S0C - S0U; \
	S1F = S1C - S1U; \
	EF  = EC  - EU;  \
	OF  = OC  - OU;  \
	PF  = PC  - PU;  \
	\
        print "Young_GC.value " YGCT; \
        print "Full_GC.value " FGCT; \
}'
}

print_bea_stats()
{
${JAVA_HOME}/bin/jstat -gc ${PidNum} | tail -1 | awk \
'{\
	HeapSize = $1; \
	NurserySize = $2; \
	UsedHeapSize = $3; \
	YC = $4; \
	OC = $5; \
	YCTime = $6; \
	OCTime = $7; \
	GCTime = $8; \
	YCPauseTime = $9; \
	OCPauseTime = $10; \
	PauseTime = $11; \
	Finalizers = $12; \
	\
	print "Young_GC.value " YCTime; \
	print "Old_GC.value " OCTime; \
	print "Young_Pause.value " YCPauseTime; \
	print "Old_Pause.value " OCPauseTime
}'
}

#
# common for all argument
#
chk_jdk

#
# autoconf
#
if [ "$1" = "autoconf" ]; then

  if [ ! -x "${JAVA_HOME}/bin/jstat" ]; then
    echo "no (No jstat found in ${JAVA_HOME}/bin)"
    exit 1
  fi

  chk_version
  if [ $? != 0 ]; then
    echo "no (Java version is invalid)"
    exit 1
  fi

  if [ ! -f "${pidfilepath}" -o ! -r "${pidfilepath}" ]; then
    echo "no (No such file ${pidfilepath} or cannot read ${pidfilepath}"
    exit 1
  fi

  echo "yes"
  exit 0
fi


#
# config
#
if [ "$1" = "config" ]; then
  if [ "${JDK_TYPE}" == "bea" ]; then
    config_bea_jdk
  else
    config_sun_jdk
  fi
  exit 0
fi

#
# Main
#
PidNum=`cat ${pidfilepath}`

if [ "${JDK_TYPE}" == "bea" ]; then
  print_bea_stats
else
  print_sun_stats
fi