GraphDashManage

#!/usr/bin/env bash

set -e

FILE="settings.sh"

USAGE="Usage: `basename $0` (start|stop|restart|forcestop|reload|increment|decrement|status|fullstatus|template) [mode1 [mode2...]]"

HELP="\

Use Gunicorn to serve GraphDash instances described in $FILE.

start       : start servers
stop        : gracefully stop servers (QUIT signal)
restart     : gracefully stop servers (QUIT signal), wait for processes to finish, then start servers
forcestop   : force stop servers (KILL signal)
reload      : reload servers (HUP signal)
increment   : increment number of workers (TTIN signal)
decrement   : decrement number of workers (TTOU signal)
status      : display status of servers
fullstatus  : display status of all servers
template    : display an template of $FILE"

TEMPLATE="\
#
# This is an template of possible $FILE file for GraphDashManage.
# Store this output and use it like this:
#
# GraphDashManage template > $FILE
# GraphDashManage start mode1
# GraphDashManage start mode2
# GraphDashManage fullstatus
# GraphDashManage stop mode1 mode2
#
ALL_MODES=(
    [mode1]='docs/graphdash.yaml'
    [mode2]='docs/graphdash.yaml'
)

ALL_PORTS=(
    [mode1]=5555
    [mode2]=6666
)

TIMEOUT=30
WORKERS=1"

check_settings () {
    if [ ! -f "$FILE" ]; then
        echo
        echo "File $FILE not found in local directory. You may generate a template with:"
        echo "$ GraphDashManage template > $FILE"
        exit 1
    fi
}

waitfor () {
    local p="$1"
    while ps -p "$p" > /dev/null; do
        echo "Waiting for $p to finish..."
        sleep 0.5
    done;
    echo "Process $p is finished!"
}

# Parsing parameters
#
ACTION=$1
case "$ACTION" in
    start|stop|restart|forcestop|reload|increment|decrement|status|fullstatus)
        ;;
    template)
        echo "$TEMPLATE"
        exit 0
        ;;
    *)
        echo "$USAGE"
        echo "$HELP"
        check_settings
        exit 1
        ;;
esac

# Settings file
#
declare -A ALL_MODES ALL_PORTS # associative arrays
WORKERS=2
TIMEOUT=30

check_settings # exit if no settings file
. "$FILE"      # overriding when sourcing settings file


# Handling fullstatus
#
MODES=${@:2}
MACHINE=$(hostname -s)

if [ "$ACTION" = "fullstatus" ]; then
    ACTION="status"
    MODES=${!ALL_MODES[@]}

elif [ ! "$MODES" ]; then
    echo "$USAGE"
    echo "Missing mode. Available modes: ${!ALL_MODES[@]}"
    exit 1
fi

# Actual stuff
#
for m in $MODES; do
    CONF="${ALL_MODES[$m]}"
    PORT="${ALL_PORTS[$m]}"
    NAME="graphdash_$m on $PORT"
    PIDF="server_$m.$MACHINE.pid"

    if [ ! "${PORT}" ]; then
        echo "\"$m\" not one of the available modes: ${!ALL_MODES[@]}"
        continue
    fi

    case "$ACTION" in
        start)
            ;;
        restart)
            # No pid file is ok, "restart" becomes "start"
            if [ ! -f "$PIDF" ]; then
                ACTION="start"
            else
                PID="`cat $PIDF`"
            fi
            ;;
        *)
            # All cases where we *need* the pid file to be there
            if [ ! -f "$PIDF" ]; then
                printf "[%-10s] file $PIDF *not* found\n" "$m"
                continue # skipping second case statement
            fi
            PID="`cat $PIDF`"
            ;;
    esac

    do_start () {
        python `which gunicorn` --error-logfile=- --access-logfile=- --timeout=$TIMEOUT --workers $WORKERS -b "0.0.0.0:$PORT" -p "$PIDF" -e CONF="$CONF" -n "$NAME" graphdash:app &
    }

    do_stop () {
        kill -QUIT "$PID"
    }

    case "$ACTION" in
        start)
            do_start
            ;;
        stop)
            do_stop
            ;;
        restart)
            do_stop || echo "Could not kill pid $PID, going on..."
            waitfor "$PID"
            do_start
            ;;
        forcestop)
            kill -KILL "$PID"
            ;;
        reload)
            kill -HUP "$PID"
            ;;
        increment)
            kill -TTIN "$PID"
            ;;
        decrement)
            kill -TTOU "$PID"
            ;;
        status)
            printf "[%-10s] file $PIDF found with pid $PID, " "$m"

            if ps -p "$PID" > /dev/null 2>&1; then
                echo "and process running (port $PORT in settings)"
            else
                echo "but process *not* running"
            fi
            ;;
    esac
done