Waiting for URL to return a propert HTTP response

wait-for-url.sh

#!/usr/bin/env bash

URL="$1"

# 10 * (30 + 1) is 310s => ~5m
MAX=10
SLEEP_SECONDS=1

IT=0

if [ -z "$URL" ]; then
  echo "usage $0: URL"
  exit 1
fi

service_ready() {
  curl --silent --max-time 30 -o /dev/null "${URL}"
}

echo "checking for service '${URL}'"
while !(service_ready); do
        if [ $IT -gt $MAX ]; then
                echo "ERROR service did not start after ${IT} polls."
                exit 1
        fi
        IT=$(($IT+1))
        sleep "$SLEEP_SECONDS"
        echo "checking for service \"${URL}\" (try $IT of $MAX)"
done
echo "ok"