stream-monitor.sh - monitors mpd while it is playing an internet stream.

#!/bin/bash
#
#stream-monitor.sh
#Developed on Debian
#Requires mpd
#
#Its an extension of http://mpd.wikia.com/wiki/Hack:stream-monitor?oldid=3932
# You can use the same Init-Script
#
#To Install:
# cp stream-monitor.sh /usr/local/bin/stream-monitor.sh
# chmod 755 /usr/local/bin/stream-monitor.sh
#
#This script monitors mpd while it is playing an internet stream. It checks every $INTERVAL_CHECK seconds
# to see if the status time variable has changed. (The stream is not playing when the time
# is not changing.) Then it restart playing.
#It also checks the current state of MPD and only take care of state 'play'. This provides you the comfort
# to use MPD like before without have to care about the watchdog when you want to pause or stop the stream.
#If the mpd daemon is not running for some reason, it starts it. i.e. if mpd were to crash.
#
#This is great for a robust stream player that keeps on playing, even after a network
# outage or stream server outage. Useful in situations where the networking is less than perfect.
#
#Check with your streaming server provider before running this. It's not nice to connect to
# a stream 24/7 if you don't need it or own it.
#
#Also does logging trough syslog.
#

INTERVAL_CHECK=5  # Seconds between checks
INTERVAL_WAIT=10  # Seconds to wait after mpd (re)start (buffering)

LOG_TAG="mpd-watchdog"

LOGGER="logger -st \"$LOG_TAG\" -- "


$LOGGER Startup with interval of $INTERVAL_CHECK Seconds


OLD_TIME=
OLD_STATE="UNKNOWN"

while sleep $INTERVAL_CHECK;
do
	STATUS=`ps -A | grep -c mpd`
        if [ $STATUS -eq 0 ]; then
                $LOGGER "no mpd processes, starting mpd"
                /etc/init.d/mpd start
                $LOGGER waiting $INTERVAL_WAIT Seconds...
                sleep $INTERVAL_WAIT
                continue
        fi

	
	TIME="0"
	STATE="UNKNOWN"

	RESP=`echo -e "status\\nclose" | nc localhost 6600 `

	IFS=": "
	while read KEY VALUE; do
		case "$KEY" in
			state) STATE="$VALUE";;
			time)  TIME="$VALUE";;
		esac
	done <<<"$RESP"
	unset IFS

	if   [ "$OLD_STATE" != "$STATE" ]; then
		$LOGGER "MPD changed state from '$OLD_STATE' to '$STATE' "
	fi
		
	if   [ "$STATE" == "play" ]; then

                if [ "$TIME" = "$OLD_TIME" ]; then
                        $LOGGER "mpd hanging, restarting"
                        mpc stop
                        mpc play
                        $LOGGER waiting $INTERVAL_WAIT Seconds...
			sleep $INTERVAL_WAIT
                fi
        fi

        OLD_STATE=$STATE
	OLD_TIME=$TIME
done

stream-monitor - Debian startup script to launch stream-monitor.sh

#! /bin/sh
set -e
#
#stream-monitor.sh launch script
#This script is a Debian startup script that handles the startup of stream-monitor.sh
#You may need to use something a little different on other OSs
#
#To Install on Debian:
# cp stream-monitor /etc/init.d/stream-monitor
# chmod 755 /etc/init.d/stream-monitor
# update-rc.d stream-monitor defaults 70

test -x /usr/local/bin/stream-monitor.sh || exit 0 #test for stream-monitor.sh in /usr/local/bin

case "$1" in
  start)
        echo -n "Starting stream-monitor"
        start-stop-daemon --start --make-pidfile --background --quiet --pidfile /var/run/stream-monitor.pid --exec /usr/local/bin/stream-monitor.sh
        echo "."
        ;;
  stop)
        echo -n "Stopping stream-monitor"
        start-stop-daemon --stop --pidfile /var/run/stream-monitor.pid
        echo "."
        ;;

  restart)
        echo -n "Restarting stream-monitor"
        start-stop-daemon --stop --pidfile /var/run/stream-monitor.pid
        start-stop-daemon --start --make-pidfile --background --quiet --pidfile /var/run/stream-monitor.pid --exec /usr/local/bin/stream-monitor.sh
        echo "."
        ;;

  *)
        echo "Usage: /etc/init.d/stream-monitor {start|stop|restart}"
        exit 1
esac

exit 0