port-wait.sh

#!/bin/bash

# Small utility to wait for port to open.
#
# usage:
#   ./port-wait.sh hostname port [timeout=10]
#
# ex:
#   ./port-wait.sh 127.0.0.1 3000

host=$1
port=$2

if [ -z "$host" ] || [ -z "$port" ]; then
    echo "usage: ./$0 hostname port [timeout=10]"
    exit 1
fi

timeout=$3
if [ -z "$timeout" ]; then
    timeout=10
fi

end_date=$(($(date +%s) + $timeout))

until nc -z $host $port; do
    sleep 1

    if [ "$end_date" -lt "$(date +%s)" ]; then
        exit 1
    fi
done