Personal Generic Service Wrapper 2/2

by @ardumont on 06 Mar 2014

In a previous article, I presented a generic service wrapper. This script was limited in one point, we could not wrap call to command with arguments.

I suggested that we could make an evolution to deal with it (without proposing one at a time).

A simple but yet elegant approach is to switch arguments position:

first one becomes the action we want the service command to execute (start, stop, etc…)
second one becomes the application's name we deal with (to stop the application we want simply its name, for example stalonetray, emacs, etc…)
the remaining arguments are the actual arguments for the full command. We simply transit them to the original command when we need to start the process (for example -t --window-type=normal, --daemon, etc…)

Here it goes:

#!/bin/bash
# Use: $0 {start|stop|restart|status} <APP>
# Generic Service Wrapper
# Example:
# $0 {start|stop|status|restart} <htop|nm-applet|some-personal-script>

### functions

# Application that this service wraps
ACTION=$1
APP=$2
shift
shift
CMD="$APP $*"

# Send a signal to the nm-applet pid (KILL to kill, 0 to know if it's alive)
app-send() {
    SIG=$1
    mypid=$(pidof $APP)
    [ -z "$mypid" ] && exit 1   # no pid so not running
    kill -$SIG $mypid && exit 0 # if pid exists and the process exists, will return 0
    exit 1 # otherwise problem
}

# Stop application
app-stop() {
    $(app-send KILL)
}

# Start application
app-start() {
    $CMD
}

# status
app-status() {
    $(app-send 0)
    ( [ $? = 0 ] && echo "$APP is running!" ) || echo "$APP is not running!"
}

### run

case "$ACTION" in
    start)
        app-start
        app-status
        ;;

    stop)
        app-stop
        app-status
        ;;

    restart)
        app-stop
        app-start
        ;;

    status)
        app-status
        ;;

    *)
        echo "Usage: $0 {start|stop|restart|status} <APP>" >&2
        exit 1
        ;;
esac

Source

Usage example:

Restarting the daemon emacs

~/bin/service/service.sh restart emacs --daemon

Restarting stalonetray

~/bin/service/service.sh restart stalonetray -t --window-type=normal

Personal Generic Service Wrapper 2/2

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