service helper package

["C.J. Adams-Collier" <cjcollier@gmail.com>]

is there something like a service-common package that provides a helper script like the following for services to source?

I'm thinking that it would belong somewhere like /usr/share/service-common/init.sh.  I have not tested the following yet, and I'm a sucky bash programmer.

# Fully qualified paths to required programs

START_STOP_DAEMON=/sbin/start-stop-daemon

CAT=/bin/cat

ECHO=/bin/echo

# Ensure that all required programs exist on the system
for REQUIRED_PROGRAM in $START_STOP_DAEMON $CAT $ECHO ; do
    if [ ! -f $REQUIRED_PROGRAM ]; then
        fatal( "Required program, '$REQUIRED_PROGRAM' does not exist." )
    fi
done

if [ -z "$SERVICE_NAME" ] || \
   [ -z "$SERVICE_DESC" ] || \
   [ -z "$SERVICE_DAEMON
" ]; then
  fatal( "Environment not configured correctly.\n\tService requires definition of the following variables:\n
SERVICE_NAME\nSERVICE_DESC\nSERVICE_DAEMON
" )
fi

# We do not want to be affected by PATH tampering.  All calls to
# external programs will be fully qualified
PATH=""

SERVICE_RUNDIR=/var/run/$SERVICE_NAME
SERVICE_PIDFILE=$SERVICE_RUNDIR/$SERVICE_NAME.pid
SERVICE_CONFDIR=/etc/$SERVICE_NAME
SERVICE_SENTINEL_FILE=$SERVICE_CONFDIR/disable
SERVICE_ENABLED=yes
SERVICE_PARAMS=""
SERVICE_INIT_SCRIPT=/etc/init.d/$SERVICE_NAME

# Source service-specific default values
. /etc/default/$SERVICE_NAME

# Kill me on all errors
set -e

# If the daemon binary does not exist, report the error and exit
if [ ! -f $SERVICE_DAEMON ]; then
    fatal( "Service daemon, '$SERVICE_DAEMON' does not exist." )
fi

# Make sure the RUNDIR exists with correct permissions
if [ ! -d "$RUNDIR" ]; then
    mkdir -p "$RUNDIR"

    # If a service user is not zero length, chown the rundir
    if [ -n "$SERVICE_USER" ]; then
        chown -R "$SERVICE_USER" "$RUNDIR"
    fi

    # If a service group is not zero length, chown the rundir
    if [ -n "$SERVICE_GROUP" ]; then
        chgrp -R "$SERVICE_GROUP" "$RUNDIR"
    fi

    # Only allow $RUNDIR to be read/written/entered by root or service
    # user/group
    chmod 770 "$RUNDIR"
fi

# main switch statement - process service state change request
case "$1" in
    start)
        start_service()
        ;;

    stop)
        stop_service()
        ;;

    reload)
        reload_service()

        ;;
    restart)
        restart_service()

        ;;
    force-reload)
        if [ "x$SERVICE_GRACEFUL_RELOAD" ]; then
            reload_service()
        else
            restart_service()
        fi

        ;;
    *)
        echo "Usage: $INIT_SCRIPT {start|stop|restart|reload|force-reload}" >&2
        exit 1
        ;;
esac

exit 0

# echo an error message and quit
fatal() {
    echo " - failed: "

    if [ -z "$1" ]; then
        echo "$1"
    else
        $CAT <<EOF
The operation failed but no output was produced. For hints on what went
wrong please refer to the system's logfiles (e.g. /var/log/syslog) or
try running the daemon in Debug mode like via "$SERVICE_DAEMON
$SERVICE_DEBUG_ARGS" (warning: this may create copious output).
EOF
    fi
    exit 1
}

# Check whether we were configured to not start the services.
check_for_no_start() {
    if [ "$SERVICE_DISABLED" = "yes" ]; then
        echo "Not starting $SERVICE_NAME: SERVICE_DISABLED set in /etc/default/$SERVICE_NAME" >&2
        exit 0
    fi
    if [ -n "$SERVICE_SENTINEL_FILE" ] && [ -e "$SERVICE_SENTINEL_FILE" ]; then
        echo "Not starting $SERVICE_NAME: $SERVICE_SENTINEL_FILE exists" >&2
        exit 0
    fi
}

start_service() {
    check_for_no_start();

    echo -n "Starting $SERVICE_DESC: "

    $START_STOP_DAEMON \
        --start \
        --quiet \
        --background \
        --make-pidfile \
        --pidfile $SERVICE_PIDFILE \
        --chdir $SERVICE_RUNDIR \
        --exec $SERVICE_DAEMON -- $SERVICE_PARAMS

    echo "$SERVICE_NAME."
}

stop_service() {
    echo -n "Stopping $SERVICE_DESC: "
    if [ ! -f $SERVICE_PIDFILE  ]; then
        echo "not running."
        exit 0
    fi

    $START_STOP_DAEMON \
        --stop \
        --oknodo \
        --quiet \
        --pidfile $SERVICE_PIDFILE \
        --exec $SERVICE_DAEMON -- $SERVICE_PARAMS

    echo "$SERVICE_NAME."
}

reload_service() {

    # If the service does not support graceful reload, tell the user
    # and fail

    if [ "x$SERVICE_GRACEFUL_RELOAD" = "xno" ]; then
        fatal( "Service does not support graceful reload.  Try 'restart' instead." )
    fi

    # If the daemon responds to changes in its config file directly
    # anyway, make this a do-nothing entry.

    if [ "x$SERVICE_AUTO_REREADS_CONFIG" = "yes" ]; then
        echo "Service '$SERVICE_NAME' reloads configuration automatically."
        exit 0
    fi

    # If the daemon can reload its config files on the fly for example
    # by sending it SIGHUP, do it here.

    echo -n "Sending SIGHUP to $SERVICE_DESC: "

    $START_STOP_DAEMON \
        --stop \
        --signal 1 \
        --quiet \
        --pidfile $SERVICE_PIDFILE \
        --exec $SERVICE_DAEMON

    echo "$SERVICE_NAME."
}

restart_service() {
    stop_service()
    sleep 1
    start_service()
}


-- 
moo.