waitForPort.sh

waitForPort.sh

#!/bin/bash

MAXTIME=30
PORTS=()
START_TSTAMP=$(date "+%s")

function help() {
  >&2 echo "Wait until a port becomes open"
  >&2 echo
  >&2 echo "Usage: $0 [options] -h HOST -p Port"
  >&2 echo "Usage: $0 [options] -c Container -p Port"
  >&2 echo
  >&2 echo "Options:"
  >&2 echo "  -p   Port, multiple notations supported"
  >&2 echo "  -h   Hostname or IP"
  >&2 echo "  -c   Container ID or Name for IP lookup"
  >&2 echo "  -t   Max wait time in seconds (default $MAXTIME)"
  >&2 echo "  -v   Verbose verboseOut"
  >&2 echo
}

# Check if nmap is installed
type nmap >/dev/null 2>&1 || {
  echo >&2 "ERROR: nmap is not installed"
  exit 1
}

# Parse CLI args
while [[ $# > 0 ]]; do
  key=$1
  case "$key" in
    -p)
      PORTS+=($2)
      shift
    ;;
    -h)
      HOST=$2
      shift
    ;;
    -c)
      CONTAINER=$2
      shift
    ;;
    -t)
      MAXTIME=$2
      shift
    ;;
    -v)
      VERBOSE=true
    ;;
    *)
      >&2 echo WARN: Ignoring unknown argument $key
    ;;
  esac
  shift # past argument or value
done


# Validate -p args
if [ ${#PORTS[@]} == 0 ] ; then
  >&2 echo ERROR: -p argument missing
  >&2 echo
  help
  exit 1
fi

# Validat if either -h or -c is present
if [ "$HOST" == "" ] && [ "$CONTAINER" == "" ] ; then
  >&2 echo ERROR: -h or -c argument missing
  >&2 echo
  help
  exit 1
fi


# output helper
function verboseOut() {
  [ "$VERBOSE" != true ] && return
  echo $@
}
function errorOut() {
  >&2 echo $@
}

# Helper to get Container IP
function getContainerIP() {
  echo $(docker inspect --format '{{ .NetworkSettings.IPAddress }}' $CONTAINER 2>/dev/null)
}


# Resolve IP from Container name
if [ "$HOST" == "" ] && [ "$CONTAINER" != "" ] ; then
  while [ "$(getContainerIP)" == "" ] ; do
    if [ $(expr $(date "+%s") - $MAXTIME) -ge $START_TSTAMP ]; then
      errorOut "Could not get IP from Container $CONTAINER within ${MAXTIME}s. Giving up."
      exit 2
    fi
    verboseOut "Waiting for Container to came up and aquire an IP"
    sleep 1
  done
  HOST=$(getContainerIP)
fi


# wait until all ports are up
LC_ALL=C
for PORT in "${PORTS[@]}" ; do
  while ! nmap --host-timeout 2 -Pn -p$PORT $HOST -oG - | grep -qF "Ports: $PORT/open"; do
    if [ $(expr $(date "+%s") - $MAXTIME) -ge $START_TSTAMP ]; then
      errorOut "Port $PORT not opened in $MAXTIME seconds. Giving up."
      exit 2
    fi
    verboseOut "Waiting for ${HOST}:${PORT}..."
    sleep 1
  done
done