UntarOperator.py

lass UntarOperator(BashOperator):

    """
    Download and unpack artifact

   :param artifact_tar_gz_name: name of artifact from previous download step
   :type url: string
   :param lookup_task_id an id of task that downloaded artifact
   :type user: string
   :param password
   :type user: string
   """
    @apply_defaults
    def __init__(self, artifact_tar_gz_name, lookup_task_id, storage_path_prefix="", *args, **kwargs):
        super(UntarOperator, self).__init__(bash_command="set me later", *args, **kwargs)
        self.storage_path_prefix = storage_path_prefix
        self.lookup_task_id = lookup_task_id
        self.artifact_tar_gz_name = artifact_tar_gz_name

    def execute(self, context):
        unpack_path = self.do_someting()
        self.bash_command = self.compose_cmd_command(path_to_tar_gz, unpack_path)
        super(UntarOperator, self).execute(context)
        # it works just fine, both self.artifact_tar_gz_name, unpack_path are strings
        logging.info("Saving path to unpacked artifact here: {}=>{}".format(self.artifact_tar_gz_name, unpack_path))
        self.xcom_push(context, self.artifact_tar_gz_name, unpack_path) # Exception here...