#!/bin/bash
# chkconfig: 345 99 01
# description: tcollector agent daemon
#
# processname: tcollector.py

# Get TSD_HOST from a file that can be set in ctx
TSD_HOST="nimbus-opentsdb.no-ip.info"


# TSD_HOST=dns.name.of.tsd
TCOLLECTOR_PATH=${TCOLLECTOR_PATH-'/usr/local/tcollector'}
test -n "$TSD_HOST" || {
    echo >&2 "TSD_HOST is not set in $0"
    exit 1
}

# Try to get hostname from instance data
HOSTNAME=$(curl -m 10 -s http://169.254.169.254/latest/meta-data/public-ipv4)
while ! echo $HOSTNAME | grep '[0-9]\+\.[0-9]\+\.[0-9]\+\.[0-9]\+' ; do
    sleep 1
    HOSTNAME=$(curl -m 10 -s http://169.254.169.254/latest/meta-data/public-ipv4)
done

PIDFILE=${PIDFILE-'/var/run/tcollector.pid'}
PROG=$TCOLLECTOR_PATH/tcollector.py
LOG=${LOG-'/var/log/tcollector.log'}
COMMAND=$1
shift
ARGS="-p 4242 -c $TCOLLECTOR_PATH/collectors -H $TSD_HOST -t host=$HOSTNAME -P $PIDFILE"
ARGS="$ARGS $@"

# Sanity checks.
test -d "$TCOLLECTOR_PATH" || {
    echo >&2 "No such directory: $TCOLLECTOR_PATH"
    echo >&2 "You might need to set the TCOLLECTOR_PATH variable in $0"
    exit 2
}

test -f "$PROG" || {
    echo >&2 "No such file: $PROG"
    echo >&2 "You might need to set the TCOLLECTOR_PATH variable in $0"
    exit 3
}

for i in "$PIDFILE" "$LOG"; do
    # If the file doesn't exist, check that we have write access to its parent
    # directory to be able to create it.
    test -e "$i" || i=`dirname "$i"`
    test -w "$i" || {
        echo >&2 "$0: error: Cannot write to $i"
        exit 4
    }
done

which_python () {
    for python in /usr/bin/python2.7 /usr/bin/python2.6 /usr/bin/python2.5 /usr/bin/python; do
        test -x "$python" && echo "$python" && return
    done
    echo >&2 'Could not find a Python interpreter'
    exit 1
}

PYTHON=$(which_python)

start () {
    echo "Starting $PROG"
    $PYTHON $PROG $ARGS >> $LOG 2>&1 &
}

# stop [signum]
stop () {
    echo "Stopping $PROG"
    pkill $1 -f "/usr/bin/python.* $PROG -c"
}

status () {
    if pgrep -f "/usr/bin/python.* $PROG -c" >/dev/null; then
        echo "$PROG" running
        return 0
    fi
    return 1
}

forcerestart () {
    stop
    try=1
    sleep 1
    while status; do
        try=$((try + 1))
        if [[ $try -gt 3 ]]; then
            stop -9
        else
            stop
        fi
        echo "Waiting for $PROG to die.."
        sleep 5
    done
    start
}

case $COMMAND in
    start)  status || start
        ;;
    force-restart)
        forcerestart
        ;;
    restart)
        # tcollector already respawns collectors if they
        # have changed on-disk, and kills old ones/starts
        # new ones.  The only thing tcollector doesn't do
        # is restart itself if itself has changed. For a more
        # graceful restart, just make sure we're running and
        # restart only if tcollector is newer on disk than
        # since it started.  This doesn't check for dependencies
        # like asyncproc.py, but that's ok.
        if status; then
            newer=$(find $PROG -newer $PIDFILE | wc -l)
            if [[ $newer -gt 0 ]]; then
                forcerestart
            fi
        else
            start
        fi
        ;;
    stop) stop
        ;;
    status) status
            exit $?
        ;;
    *)  echo >&2 "usage: $0 <start [args]|stop|restart|status|force-restart>"
        exit 1
        ;;
esac