wait-for-it.sh to Check if MySQL service is running using environment variables

wait-for-it.sh

#!/bin/bash
set -e
host="$1"
shift
cmd="$@"
until mysql -hmysql -p"3306" -u"${database__connection__user}" -p"${database__connection__password}" 
-D"${database__connection__database}" ; do
  >&2 echo "MySQL is unavailable - sleeping"
  sleep 1
done
>&2 echo "MySQL is up - executing command"
exec "$@"