Awaint instances ready in python

await_instances.py

def await_instances_ready(instances: List[str]):
    """
    Block until all instances in the list become ready.

    Args:
        instances: List of instances external IPs.

    Raises:
        Exception: If we do not own given external IPs.
    """
    while True:
        df = get_instances_df()
        df = df[df.external_ip.isin(instances)]

        if len(df) != len(instances):
            missing_instances = set(instances).difference(set(df.external_ip))
            raise Exception(
                "Request to await non-existent instances {}".format(
                    missing_instances))

        not_ready = df[df.status != "RUNNING"]
        if len(not_ready) > 0:
            logger.info(
                "Awaiting ready instances. {} not ready yet".format(not_ready))
            time.sleep(2)
        else:
            return