How can I get the url of the host there I want do build docker

I need to build docker conters using DockerOperator on a remote host via Airflow determining my ockerOperator

task1 = DockerOperator(
    task_id="task1",
    image=image,
    docker_url=DOCKER_URL,
    auto_remove=True,
    api_version="auto",
    force_pull=True
}

I Have a remote server like this: user@12.345.67.890 which format is correct for the docker_url parameter?