def publish(dataset_uri):
    """Return access URL to HTTP enabled (published) dataset.

    Exits with error code 1 if the dataset_uri is not a dataset.
    Exits with error code 2 if the dataset cannot be HTTP enabled.
    """

    try:
        dataset = dtoolcore.DataSet.from_uri(dataset_uri)
    except dtoolcore.DtoolCoreTypeError:
        print("Not a dataset: {}".format(dataset_uri))
        sys.exit(1)

    try:
        access_uri = dataset._storage_broker.http_enable()
    except AttributeError:
        print(
            "Datasets of type '{}' cannot be published using HTTP".format(
                dataset._storage_broker.key)
        )
        sys.exit(2)

    return access_uri