bash: Wait for socket to became active

waitforsocket.sh

#!/bin/bash

# Wait for a socket on given host and port to became active.
# Will exit with statuscode 0 if succeeded, -1 otherwise.
# Originally got it from the blog post: https://developer.atlassian.com/blog/2015/03/docker-systemd-socket-activation/

host=$1
port=$2
tries=600

for ((i=0; i<$tries; i++)); do
    if nc -z $host $port > /dev/null ; then
      exit 0
    fi

    sleep 0.1
done

exit -1