Java Threaddump

threaddump.sh

#!/bin/bash

# Usage: threaddump.sh <thread count threshold> <process name>

# Example:
# Run this command `nohup sh threaddump.sh 500 tomcat7 &` to capture a thread
# dump when httpd connections exceeds 500.
# 
# Logs are written to `nohump.out` in the users home directory.
# Thread dump for tomcat will be written to `/var/log/tomcat7/catalina.out`.

THREAD_COUNT_THRESHOLD="$1"
TARGET_PROCESS_NAME="$2"

function count_httpd_threads {
    ps -e | grep --count httpd
}

function get_java_pid {
    PROCESS_NAME="$1"
    sudo jps -l -v | awk --assign P=${PROCESS_NAME} '/P/ { print $1 }'
}

while true; do
    THREAD_COUNT=`count_httpd_threads`
    if [ "${THREAD_COUNT}" -ge "${THREAD_COUNT_THRESHOLD}" ]; then
        PID=`get_java_pid ${TARGET_PROCESS_NAME}`
        if [ -n "$PID" ]; then
            echo "[$(date --iso-8601=seconds)] Thread dump [${TARGET_PROCESS_NAME}] with pid [$PID] since thread count [${THREAD_COUNT}] breaches threadshold [${THREAD_COUNT_THRESHOLD}]"
            sudo kill -3 "$PID"
        else
            echo "ERROR: process [${TARGET_PROCESS_NAME}] not running"
        fi
    fi
    sleep 10
done