entrypoint

#!/bin/bash
set -eo pipefail

usage() {
  echo ""
  echo "usage: $0 [-p] [-c] [-t]"
  echo ""
  echo "optional arguments:"
  echo " -p    only test exposed ports from the linked container that are in this list"
  echo " -c    custom connection(s) to test, host:port, multiple seperated by comma"
  echo " -t    timeout after which connection attempt will fail, default 30"
  echo ""
  echo " Example: $0 -c google.com:443,github.com:443 -t 15"
  echo "          $0 -p 8080"
}

set -e

timeout=${TIMEOUT:-30}

# Parse arguments
while getopts ":t:c:p:" opt; do
  case $opt in
    t)
      timeout=$OPTARG
      if ! echo "$timeout" | grep -qE '^[0-9]+$'; then
        echo "Invalid timeout number: $timeout" >&2
        exit 1
      fi
      ;;
    c)
      TARGETS="$OPTARG"
      ;;
    p)
      PORTS="$OPTARG"
      ;;
    \?)
      set +x
      echo "Invalid option: -$OPTARG" >&2
      usage
      exit 1
      ;;
    :)
      set +x
      echo "Option -$OPTARG requires an argument." >&2
      usage
      exit 1
      ;;
  esac
done

if [[ -n "$PORTS" ]]; then
  ports=$(echo "$PORTS" | sed -e 's/,/ /g' -e 's/\s+/\n/g')
fi

# our target format is a newline-delimited list where each item is "host:ip"
if [[ -z "$TARGETS" ]]; then
  # empty TARGETS variable will default to checking all host/ports exposed
  uris=$(env | grep _TCP= | cut -d= -f2 | cut -c7-)

  if [[ -n "$PORTS" ]]; then
    urisinc=""
    for uri in $uris; do
      port=$(echo "$uri" | cut -d: -f2)
      if [[ -n "${port}" ]]; then
        #check if port should be checked
        for portex in $ports; do
          if [[ "$portex" == "$port" ]]; then
            if [[ -z "$urisinc" ]]; then
              urisinc="$urisinc $uri"
            else
              urisinc="$uri"
            fi
            continue 2
          fi
        done
      else
        echo "Not checking $uri because port is not included."
      fi
    done
    uris=$urisinc
  fi

  if [[ $(echo "$uris" | wc -w) -lt 1 ]]; then
    echo "The linked container(s) export no ports and you didn't specify any manual targets." >&2
    usage
    exit 1
  fi
else
  uris=$(echo "$TARGETS" | sed -e 's/,/ /g' -e 's/\s+/\n/g' | uniq)
fi

# wait for each target
if [[ -z "$uris" ]]; then
  echo "No wait targets found." >&2
  usage
  exit 1
fi

for uri in $uris; do
  host=$(echo "$uri" | cut -d: -f1)
  port=$(echo "$uri" | cut -d: -f2)
  if [[ -n "${host}" ]] && [[ -n "${port}" ]]; then
    echo -n "Waiting for ${uri}  ."
    timestamp="$(date +%s)"
    totalelapseds=0
    totalalloweds=$timeout
    while [[ "$totalelapseds" -lt "$totalalloweds" ]] && ! nc -z -w 1 "$host" "$port"; do
      current_date="$(date +%s)"
      elapseds="$((current_date - timestamp))"
      if [[ $elapseds -lt 1 ]]; then
        sleep 1
        elapseds=$((elapseds + 1))
      fi
      totalelapseds=$((totalelapseds + elapseds))
      echo -n '.'
      timestamp="$(date +%s%N)"
    done

    if [[ "$totalelapseds" -lt "$totalalloweds" ]]; then
      echo "  up!"
    else
      echo "  ERROR: unable to connect" >&2
      exit 1
    fi
  else
    echo "  SKIP: Missing host or port in $uri"
  fi
done
echo "Everything is up"
exit 0