#!/usr/bin/env bash # Use this script to test if a given TCP host/port are available

WAITFORIT_cmdname=${0##*/}

echoerr() { if [[ $WAITFORIT_QUIET -ne 1 ]]; then echo “$@” 1>&2; fi }

usage() {

cat << USAGE >&2

Usage:

$WAITFORIT_cmdname host:port [-s] [-t timeout] [-- command args]
-h HOST | --host=HOST       Host or IP under test
-p PORT | --port=PORT       TCP port under test
                            Alternatively, you specify the host and port as host:port
-s | --strict               Only execute subcommand if the test succeeds
-q | --quiet                Don't output any status messages
-t TIMEOUT | --timeout=TIMEOUT
                            Timeout in seconds, zero for no timeout
-- COMMAND ARGS             Execute command with args after the test finishes

USAGE

exit 1

}

wait_for() {

if [[ $WAITFORIT_TIMEOUT -gt 0 ]]; then
    echoerr "$WAITFORIT_cmdname: waiting $WAITFORIT_TIMEOUT seconds for $WAITFORIT_HOST:$WAITFORIT_PORT"
else
    echoerr "$WAITFORIT_cmdname: waiting for $WAITFORIT_HOST:$WAITFORIT_PORT without a timeout"
fi
WAITFORIT_start_ts=$(date +%s)
while :
do
    if [[ $WAITFORIT_ISBUSY -eq 1 ]]; then
        nc -z $WAITFORIT_HOST $WAITFORIT_PORT
        WAITFORIT_result=$?
    else
        (echo > /dev/tcp/$WAITFORIT_HOST/$WAITFORIT_PORT) >/dev/null 2>&1
        WAITFORIT_result=$?
    fi
    if [[ $WAITFORIT_result -eq 0 ]]; then
        WAITFORIT_end_ts=$(date +%s)
        echoerr "$WAITFORIT_cmdname: $WAITFORIT_HOST:$WAITFORIT_PORT is available after $((WAITFORIT_end_ts - WAITFORIT_start_ts)) seconds"
        break
    fi
    sleep 1
done
return $WAITFORIT_result

}

wait_for_wrapper() {

# In order to support SIGINT during timeout: http://unix.stackexchange.com/a/57692
if [[ $WAITFORIT_QUIET -eq 1 ]]; then
    timeout $WAITFORIT_BUSYTIMEFLAG $WAITFORIT_TIMEOUT $0 --quiet --child --host=$WAITFORIT_HOST --port=$WAITFORIT_PORT --timeout=$WAITFORIT_TIMEOUT &
else
    timeout $WAITFORIT_BUSYTIMEFLAG $WAITFORIT_TIMEOUT $0 --child --host=$WAITFORIT_HOST --port=$WAITFORIT_PORT --timeout=$WAITFORIT_TIMEOUT &
fi
WAITFORIT_PID=$!
trap "kill -INT -$WAITFORIT_PID" INT
wait $WAITFORIT_PID
WAITFORIT_RESULT=$?
if [[ $WAITFORIT_RESULT -ne 0 ]]; then
    echoerr "$WAITFORIT_cmdname: timeout occurred after waiting $WAITFORIT_TIMEOUT seconds for $WAITFORIT_HOST:$WAITFORIT_PORT"
fi
return $WAITFORIT_RESULT

}

# process arguments while [[ $# -gt 0 ]] do

case "$1" in
    *:* )
    WAITFORIT_hostport=(${1//:/ })
    WAITFORIT_HOST=${WAITFORIT_hostport[0]}
    WAITFORIT_PORT=${WAITFORIT_hostport[1]}
    shift 1
    ;;
    --child)
    WAITFORIT_CHILD=1
    shift 1
    ;;
    -q | --quiet)
    WAITFORIT_QUIET=1
    shift 1
    ;;
    -s | --strict)
    WAITFORIT_STRICT=1
    shift 1
    ;;
    -h)
    WAITFORIT_HOST="$2"
    if [[ $WAITFORIT_HOST == "" ]]; then break; fi
    shift 2
    ;;
    --host=*)
    WAITFORIT_HOST="${1#*=}"
    shift 1
    ;;
    -p)
    WAITFORIT_PORT="$2"
    if [[ $WAITFORIT_PORT == "" ]]; then break; fi
    shift 2
    ;;
    --port=*)
    WAITFORIT_PORT="${1#*=}"
    shift 1
    ;;
    -t)
    WAITFORIT_TIMEOUT="$2"
    if [[ $WAITFORIT_TIMEOUT == "" ]]; then break; fi
    shift 2
    ;;
    --timeout=*)
    WAITFORIT_TIMEOUT="${1#*=}"
    shift 1
    ;;
    --)
    shift
    WAITFORIT_CLI=("$@")
    break
    ;;
    --help)
    usage
    ;;
    *)
    echoerr "Unknown argument: $1"
    usage
    ;;
esac

done

if [[ “$WAITFORIT_HOST” == “” || “$WAITFORIT_PORT” == “” ]]; then

echoerr "Error: you need to provide a host and port to test."
usage

fi

WAITFORIT_TIMEOUT=${WAITFORIT_TIMEOUT:-15} WAITFORIT_STRICT=${WAITFORIT_STRICT:-0} WAITFORIT_CHILD=${WAITFORIT_CHILD:-0} WAITFORIT_QUIET=${WAITFORIT_QUIET:-0}

# check to see if timeout is from busybox? WAITFORIT_TIMEOUT_PATH=$(type -p timeout) WAITFORIT_TIMEOUT_PATH=$(realpath $WAITFORIT_TIMEOUT_PATH 2>/dev/null || readlink -f $WAITFORIT_TIMEOUT_PATH) if [[ $WAITFORIT_TIMEOUT_PATH =~ “busybox” ]]; then

WAITFORIT_ISBUSY=1
WAITFORIT_BUSYTIMEFLAG="-t"

else

WAITFORIT_ISBUSY=0
WAITFORIT_BUSYTIMEFLAG=""

fi

if [[ $WAITFORIT_CHILD -gt 0 ]]; then

wait_for
WAITFORIT_RESULT=$?
exit $WAITFORIT_RESULT

else

if [[ $WAITFORIT_TIMEOUT -gt 0 ]]; then
    wait_for_wrapper
    WAITFORIT_RESULT=$?
else
    wait_for
    WAITFORIT_RESULT=$?
fi

fi

if [[ $WAITFORIT_CLI != “” ]]; then

if [[ $WAITFORIT_RESULT -ne 0 && $WAITFORIT_STRICT -eq 1 ]]; then
    echoerr "$WAITFORIT_cmdname: strict mode, refusing to execute subprocess"
    exit $WAITFORIT_RESULT
fi
exec "${WAITFORIT_CLI[@]}"

else

exit $WAITFORIT_RESULT

fi