#! /bin/sh
# Copyright 2016 Matthew Wall, all rights reserved
# init script to run multiple instances of weewx
#
# each weewx instance is identified by name.  that name is used to identify the
# configuration and pid files.
#
# this init script expects the following configuration:
#   /etc/weewx/a.conf
#   /etc/weewx/b.conf
#   /var/run/weewx-a.pid
#   /var/run/weewx-b.pid
#
# with the appropriate rsyslog and logrotate configurations:
#   /var/log/weewx/a.log
#   /var/log/weewx/b.log
#
# to configure the script, override variables in /etc/default/weewx-multi
# for example:
#
#   WEEWX_INSTANCES="vantage acurite"
#   WEEWX_BINDIR=/opt/weewx/bin
#   WEEWX_CFGDIR=/etc/weewx

### BEGIN INIT INFO
# Provides:          weewx-multi
# Required-Start:    $local_fs $remote_fs $syslog $time
# Required-Stop:     $local_fs $remote_fs $syslog
# Default-Start:     2 3 4 5
# Default-Stop:      0 1 6
# Short-Description: weewx-multi
# Description:       Manages multiple instances of weewx
### END INIT INFO

PATH=/sbin:/usr/sbin:/bin:/usr/bin

WEEWX_INSTANCES="no_instances_specified"
WEEWX_USER=root:root
WEEWX_BINDIR=/home/weewx/bin
WEEWX_CFGDIR=/home/weewx

# Try to keep systemd from screwing everything up
export SYSTEMCTL_SKIP_REDIRECT=1

# Read configuration variable file if it is present
[ -r /etc/default/weewx-multi ] && . /etc/default/weewx-multi

DESC=weewx
DAEMON=$WEEWX_BINDIR/weewxd

# Exit if the package is not installed
if [ ! -x "$DAEMON" ]; then
    echo "The $DESC daemon is not installed at $DAEMON"
    exit 0
fi

# Load the VERBOSE setting and other rcS variables
. /lib/init/vars.sh

# Define LSB log_* functions.
# Depend on lsb-base (>= 3.0-6) to ensure that this file is present.
. /lib/lsb/init-functions

# start the daemon
#   0 if daemon has been started
#   1 if daemon was already running
#   2 if daemon could not be started
do_start() {
    INSTANCE=$1
    NAME=weewx-$INSTANCE
    PIDFILE=/var/run/$NAME.pid
    CFGFILE=$WEEWX_CFGDIR/$INSTANCE.conf
    DAEMON_ARGS="--daemon --log-label $NAME --pidfile=$PIDFILE $CFGFILE"

    if [ ! -f "$CFGFILE" ]; then
        echo "The instance $INSTANCE does not have a config at $CFGFILE"
        return 2
    fi

    NPROC=$(count_procs $INSTANCE)
    if [ $NPROC != 0 ]; then
        return 1
    fi
    start-stop-daemon --start --chuid $WEEWX_USER --pidfile $PIDFILE --exec $DAEMON -- $DAEMON_ARGS || return 2
    return 0
}

# stop the daemon
#   0 if daemon has been stopped
#   1 if daemon was already stopped
#   2 if daemon could not be stopped
#   other if a failure occurred
do_stop() {
    INSTANCE=$1
    NAME=weewx-$INSTANCE
    PIDFILE=/var/run/$NAME.pid

    # bail out if the app is not running
    NPROC=$(count_procs $INSTANCE)
    if [ $NPROC = 0 ]; then
        return 1
    fi
    # bail out if there is no pid file
    if [ ! -f $PIDFILE ]; then
        return 1
    fi
    start-stop-daemon --stop --pidfile $PIDFILE
    # we cannot trust the return value from start-stop-daemon
    RETVAL=2
    c=0
    while [ $c -lt 24 -a "$RETVAL" = "2" ]; do
        c=`expr $c + 1`
        # process may not really have completed, so check it
        NPROC=$(count_procs $INSTANCE)
        if [ $NPROC = 0 ]; then
            RETVAL=0
        else
            echo -n "."
            sleep 5
        fi
    done
    if [ "$RETVAL" = "0" -o "$RETVAL" = "1" ]; then
        # delete the pid file just in case
        rm -f $PIDFILE
    fi
    return "$RETVAL"
}

# send a SIGHUP to the daemon
do_reload() {
    INSTANCE=$1
    NAME=weewx-$INSTANCE
    PIDFILE=/var/run/$NAME.pid

    start-stop-daemon --stop --signal 1 --quiet --pidfile $PIDFILE
    return 0
}

do_status() {
    INSTANCE=$1
    NAME=weewx-$INSTANCE
    NPROC=$(count_procs $INSTANCE)
    echo -n "$INSTANCE is "
    if [ $NPROC = 0 ]; then
        echo -n "not "
    fi
    echo "running."
}

count_procs() {
    INSTANCE=$1
    NAME=weewx-$INSTANCE
    NPROC=`ps ax | grep $DAEMON | grep $NAME.pid | wc -l`
    echo $NPROC
}

CMD=$1
if [ "$1" != "" ]; then
    shift
fi
INSTANCES="$@"
if [ "$INSTANCES" = "" ]; then
    INSTANCES=$WEEWX_INSTANCES
fi

case "$CMD" in
    start)
        for i in $INSTANCES; do
	    [ "$VERBOSE" != no ] && log_daemon_msg "Starting $DESC" "$i"
	    do_start $i
	    case "$?" in
		0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;;
		2) [ "$VERBOSE" != no ] && log_end_msg 1 ;;
	    esac
        done
	;;
    stop)
        for i in $INSTANCES; do
	    [ "$VERBOSE" != no ] && log_daemon_msg "Stopping $DESC" "$i"
	    do_stop $i
	    case "$?" in
		0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;;
		2) [ "$VERBOSE" != no ] && log_end_msg 1 ;;
	    esac
        done
	;;
    status)
        for i in $INSTANCES; do
            do_status "$i"
        done
        ;;
    reload|force-reload)
        for i in $INSTANCES; do
	    log_daemon_msg "Reloading $DESC" "$i"
	    do_reload $i
	    log_end_msg $?
        done
	;;
    restart)
        for i in $INSTANCES; do
	    log_daemon_msg "Restarting $DESC" "$i"
	    do_stop $i
	    case "$?" in
	        0|1)
		    do_start $i
		    case "$?" in
			0) log_end_msg 0 ;;
			1) log_end_msg 1 ;; # Old process is still running
			*) log_end_msg 1 ;; # Failed to start
		    esac
		    ;;
	        *)
	  	# Failed to stop
		    log_end_msg 1
		    ;;
	    esac
        done
	;;
    *)
	echo "Usage: $0 {start|stop|restart|reload} [instance]" >&2
	exit 3
	;;
esac