dist-play-app-initd

#!/bin/bash
#
# =========================================================================
# Copyright 2014 Rado Buransky, Dominion Marine Media
#
# 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.
# ========================================================================
#
#
# Check this blog post I wrote with detailed information:
# http://buransky.com/play-framework/init-d-shell-script-for-play-framework-distributed-application/
#
#
# Script to start, stop and check status of a Play framework application. It requires
# the Play application to be packaged using the "dist" command. Before you run the script,
# you have to set values of NAME, PORT and APP_DIR variables.
#
#         NAME – name of the application, must be the same as the name of shell script
#                generated by Play framework to run the app
#         PORT – port number at which the app should run
#         APP_DIR – path to directory where you have unzipped the packaged app
#
#
# Usage: control.sh {start|stop|status|restart}
#    port - requred for start and restart commands
#
# Example: control.sh restart app-name 9000
#
#
# The script uses RUNNING_PID file generated by Play framework which contains ID of the
# application server process.
#
#
# START YOUR APPLICATION WHEN MACHINE STARTS
# ==========================================
#
# The script uses RUNNING_PID file generated by Play framework which contains ID of
# the application server process.
#
#
# SAFE START
# ==========
#
# After starting the application the script checks whether the RUNNING_PID file has
# been created and whether the process is really running. After that it uses wget
# utility to issue an HTTP GET request for root document to do yet another check
# whether the server is alive. Of course this assumes that your application serves
# this document. If you don’t like (or have) wget I have provided curl version for
# your convenience as well.
#
#
# SAFE STOP
# =========
#
# Stop checks whether the process whose ID is in the RUNNING_PID file really belongs
# to your application. This is an important check so that we don’t kill an innocent
# process by accident. Then it sends termination signals to the process starting
# with the most gentle ones until the process dies.
#
#

# Script arguments (start, stop, restart or status)
COMMAND=$1

# ***********************************************
# *************  Set these variables  ***********

NAME=
PORT=
APP_DIR=

# Example:
 NAME=jugjane
 PORT=9000
 APP_DIR=/home/rado/bin/jugjane-1.1-SNAPSHOT

# ***********************************************
# ***********************************************

# Additional arguments to be passed to the Play application
APP_ARGS=-Dhttp.port=${PORT}

# Path to the RUNNING_PID file containing process ID
PID_FILE=$APP_DIR/RUNNING_PID

# Helper functions
echoProgress()
{
	setColor 6
        printf "%-70s" "$1..."
	resetColor
	return 0
}

echoError()
{
	setColor 6
        printf "ERROR"
        if [ ! -z "$1" ]
        then
		resetColor
                printf " [$1]"
        fi
        printf "\n"
	resetColor
	return 0
}

echoOK()
{
	setColor 2
        printf "OK"
        if [ ! -z "$1" ]
        then
		resetColor
                printf " [$1]"
        fi
        printf "\n"
	resetColor
	return 0
}

checkResult()
{
        if [ "$1" -ne 0 ]
        then
                echoError "$2"
                exit 1
        fi
}

setColor()
{
        tput setaf $1 2>/dev/null
}

resetColor()
{
        tput sgr0 2>/dev/null
}

# Checks if RUNNING_PID file exists and whether the process is really running.
checkPidFile()
{
	if [ -f $PID_FILE ]
	then
		if ps -p `cat $PID_FILE` > /dev/null
		then
			# The file exists and the process is running
			return 1
		else
			# The file exitsts, but the process is dead
			return 2
		fi
	fi

	# The file doesn't exist
	return 0
}

# Gently kill the given process
kill_softly()
{
	SAFE_CHECK=`ps $@ | grep [-]Duser.dir=$APP_DIR`
	if [ -z "$SAFE_CHECK" ]
	then
		# Process ID doesn't belong to expected application! Don't kill it!
		return 1
	else
		# Send termination signals one by one
		for sig in TERM HUP INT QUIT PIPE KILL; do
			if ! kill -$sig "$@" > /dev/null 2>&1 ;
			then
				break
			fi
			sleep 2
		done
	fi
}

# Get process ID from RUNNING_PID file and print it
printPid()
{
	PID=`cat $PID_FILE`
	printf "PID=$PID"
}

# Check port input argument
checkPort()
{
	if [ -z "$PORT" ]
	then
		echoError "Port not set!"
		return 1
	fi
}

# Check input arguments
checkArgs()
{
	# Check command
	case "$COMMAND" in
		start | stop | restart | status) ;;
		*)
			echoError "Unknown command"
			return 1
		;;
	esac

	# Check application name
	if [ -z "$NAME" ]
	then
		echoError "Application name not set!"
		return 1
	fi

	# Check application directory
	if [ -z "$APP_DIR" ]
	then
		echoError "Application installation directory not set!"
		return 1
	fi

	# Check port
	case "$COMMAND" in
		start | restart)
			checkPort
			if [ $? != 0 ]
			then
				return 1
			fi
		;;
	esac
}

checkAppStarted()
{
	# Wait a bit 
	sleep 3

	# Check if RUNNING_PID file exists and if process is really running
	checkPidFile
	if [ $? != 1 ]
	then
		echoError
		cat $TMP_LOG 1>&2
		exit 1
	fi

	local HTTP_RESPONSE_CODE

	# Issue HTTP GET request using wget to check if the app is really started. Of course this
	# command assumes that your server supports GET for the root URL.
	HTTP_RESPONSE_CODE=`wget -SO- "http://localhost:$PORT/" 2>&1 | grep "HTTP/" | awk '{print $2}'`

	# The same functionality but using curl. For your convenience.
	#HTTP_RESPONSE_CODE=`curl --connect-timeout 20 --retry 3 -o /dev/null --silent --write-out "%{http_code}" http://localhost:$PORT/`

	checkResult $? "no response from server, timeout"

	if [ $HTTP_RESPONSE_CODE != 200 ]
	then
		echoError "HTTP GET / = $HTTP_RESPONSE_CODE"
		exit 1
	fi
}

# Check input arguments
checkArgs
if [ $? != 0 ]
then
	echo "Usage: $0 {start|stop|status|restart}"
	exit 1
fi

case "${COMMAND}" in
	start)
		echoProgress "Starting $NAME at port $PORT"

		checkPidFile
		case $? in
			1)	echoOK "$(printPid) already started"
				exit ;;
			2)	# Delete the RUNNING_PID FILE			
				rm $PID_FILE ;;		
		esac

		SCRIPT_TO_RUN=$APP_DIR/bin/$NAME
		if [ ! -f $SCRIPT_TO_RUN ]
		then
			echoError "Play script doesn't exist!"
			exit 1
		fi
			
		# * * * Run the Play application * * *
		TMP_LOG=`mktemp`
		PID=`$SCRIPT_TO_RUN $APP_ARGS > /dev/null 2>$TMP_LOG & echo $!`

		# Check if successfully started
		if [ $? != 0 ]
		then
			echoError
			exit 1
		else
			checkAppStarted
			echoOK "PID=$PID"
		fi
	;;
	status)
		echoProgress "Checking $NAME at port $PORT"
		checkPidFile
		case $? in
			0)	echoOK "not running" ;;
			1)	echoOK "$(printPid) running" ;;
			2)	echoError "process dead but RUNNING_PID file exists" ;;
		esac
	;;
	stop)
		echoProgress "Stopping $NAME"
		checkPidFile
		case $? in
			0)	echoOK "wasn't running" ;;
			1)	PRINTED_PID=$(printPid)
				kill_softly `cat $PID_FILE`
				if [ $? != 0 ]
				then
					echoError "$PRINTED_PID doesn't belong to $NAME! Human intervention is required."
					exit 1
				else
					echoOK "$PRINTED_PID stopped"
				fi ;;
			2)	echoError "RUNNING_PID exists but process is already dead" ;;
		esac
	;;

	restart)
		$0 stop $NAME $PORT
		if [ $? == 0 ]
		then
			$0 start $NAME $PORT
			if [ $? == 0 ]
			then
				# Success
				exit
			fi
		fi
		exit 1
	;;
esac