#!/usr/bin/env bash
#   Use this script to test if a given TCP host/port are availableWAITFORIT_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 testAlternatively, 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=TIMEOUTTimeout in seconds, zero for no timeout-- COMMAND ARGS             Execute command with args after the test finishes
USAGEexit 1
}wait_for()
{if [[ $WAITFORIT_TIMEOUT -gt 0 ]]; thenechoerr "$WAITFORIT_cmdname: waiting $WAITFORIT_TIMEOUT seconds for $WAITFORIT_HOST:$WAITFORIT_PORT"elseechoerr "$WAITFORIT_cmdname: waiting for $WAITFORIT_HOST:$WAITFORIT_PORT without a timeout"fiWAITFORIT_start_ts=$(date +%s)while :doif [[ $WAITFORIT_ISBUSY -eq 1 ]]; thennc -z $WAITFORIT_HOST $WAITFORIT_PORTWAITFORIT_result=$?else(echo > /dev/tcp/$WAITFORIT_HOST/$WAITFORIT_PORT) >/dev/null 2>&1WAITFORIT_result=$?fiif [[ $WAITFORIT_result -eq 0 ]]; thenWAITFORIT_end_ts=$(date +%s)echoerr "$WAITFORIT_cmdname: $WAITFORIT_HOST:$WAITFORIT_PORT is available after $((WAITFORIT_end_ts - WAITFORIT_start_ts)) seconds"breakfisleep 1donereturn $WAITFORIT_result
}wait_for_wrapper()
{# In order to support SIGINT during timeout: http://unix.stackexchange.com/a/57692if [[ $WAITFORIT_QUIET -eq 1 ]]; thentimeout $WAITFORIT_BUSYTIMEFLAG $WAITFORIT_TIMEOUT $0 --quiet --child --host=$WAITFORIT_HOST --port=$WAITFORIT_PORT --timeout=$WAITFORIT_TIMEOUT &elsetimeout $WAITFORIT_BUSYTIMEFLAG $WAITFORIT_TIMEOUT $0 --child --host=$WAITFORIT_HOST --port=$WAITFORIT_PORT --timeout=$WAITFORIT_TIMEOUT &fiWAITFORIT_PID=$!trap "kill -INT -$WAITFORIT_PID" INTwait $WAITFORIT_PIDWAITFORIT_RESULT=$?if [[ $WAITFORIT_RESULT -ne 0 ]]; thenechoerr "$WAITFORIT_cmdname: timeout occurred after waiting $WAITFORIT_TIMEOUT seconds for $WAITFORIT_HOST:$WAITFORIT_PORT"fireturn $WAITFORIT_RESULT
}# process arguments
while [[ $# -gt 0 ]]
docase "$1" in*:* )WAITFORIT_hostport=(${1//:/ })WAITFORIT_HOST=${WAITFORIT_hostport[0]}WAITFORIT_PORT=${WAITFORIT_hostport[1]}shift 1;;--child)WAITFORIT_CHILD=1shift 1;;-q | --quiet)WAITFORIT_QUIET=1shift 1;;-s | --strict)WAITFORIT_STRICT=1shift 1;;-h)WAITFORIT_HOST="$2"if [[ $WAITFORIT_HOST == "" ]]; then break; fishift 2;;--host=*)WAITFORIT_HOST="${1#*=}"shift 1;;-p)WAITFORIT_PORT="$2"if [[ $WAITFORIT_PORT == "" ]]; then break; fishift 2;;--port=*)WAITFORIT_PORT="${1#*=}"shift 1;;-t)WAITFORIT_TIMEOUT="$2"if [[ $WAITFORIT_TIMEOUT == "" ]]; then break; fishift 2;;--timeout=*)WAITFORIT_TIMEOUT="${1#*=}"shift 1;;--)shiftWAITFORIT_CLI=("$@")break;;--help)usage;;*)echoerr "Unknown argument: $1"usage;;esac
doneif [[ "$WAITFORIT_HOST" == "" || "$WAITFORIT_PORT" == "" ]]; thenechoerr "Error: you need to provide a host and port to test."usage
fiWAITFORIT_TIMEOUT=${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" ]]; thenWAITFORIT_ISBUSY=1WAITFORIT_BUSYTIMEFLAG="-t"elseWAITFORIT_ISBUSY=0WAITFORIT_BUSYTIMEFLAG=""
fiif [[ $WAITFORIT_CHILD -gt 0 ]]; thenwait_forWAITFORIT_RESULT=$?exit $WAITFORIT_RESULT
elseif [[ $WAITFORIT_TIMEOUT -gt 0 ]]; thenwait_for_wrapperWAITFORIT_RESULT=$?elsewait_forWAITFORIT_RESULT=$?fi
fiif [[ $WAITFORIT_CLI != "" ]]; thenif [[ $WAITFORIT_RESULT -ne 0 && $WAITFORIT_STRICT -eq 1 ]]; thenechoerr "$WAITFORIT_cmdname: strict mode, refusing to execute subprocess"exit $WAITFORIT_RESULTfiexec "${WAITFORIT_CLI[@]}"
elseexit $WAITFORIT_RESULT
fi