Source code for airflow.contrib.operators.gcs_download_operator

# -*- coding: utf-8 -*-
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import sys

from airflow.contrib.hooks.gcs_hook import GoogleCloudStorageHook
from airflow.models import BaseOperator
from airflow.utils.decorators import apply_defaults


[docs]class GoogleCloudStorageDownloadOperator(BaseOperator): """ Downloads a file from Google Cloud Storage. :param bucket: The Google cloud storage bucket where the object is. :type bucket: string :param object: The name of the object to download in the Google cloud storage bucket. :type object: string :param filename: The file path on the local file system (where the operator is being executed) that the file should be downloaded to. If false, the downloaded data will not be stored on the local file system. :type filename: string :param store_to_xcom_key: If this param is set, the operator will push the contents of the downloaded file to XCom with the key set in this parameter. If false, the downloaded data will not be pushed to XCom. :type store_to_xcom_key: string :param google_cloud_storage_conn_id: The connection ID to use when connecting to Google cloud storage. :type google_cloud_storage_conn_id: string :param delegate_to: The account to impersonate, if any. For this to work, the service account making the request must have domain-wide delegation enabled. :type delegate_to: string """ template_fields = ('bucket', 'object', 'filename', 'store_to_xcom_key',) ui_color = '#f0eee4' @apply_defaults def __init__(self, bucket, object, filename=False, store_to_xcom_key=False, google_cloud_storage_conn_id='google_cloud_storage_default', delegate_to=None, *args, **kwargs): super(GoogleCloudStorageDownloadOperator, self).__init__(*args, **kwargs) self.bucket = bucket self.object = object self.filename = filename self.store_to_xcom_key = store_to_xcom_key self.google_cloud_storage_conn_id = google_cloud_storage_conn_id self.delegate_to = delegate_to def execute(self, context): self.log.info('Executing download: %s, %s, %s', self.bucket, self.object, self.filename) hook = GoogleCloudStorageHook(google_cloud_storage_conn_id=self.google_cloud_storage_conn_id, delegate_to=self.delegate_to) file_bytes = hook.download(self.bucket, self.object, self.filename) if self.store_to_xcom_key: if sys.getsizeof(file_bytes) < 48000: context['ti'].xcom_push(key=self.store_to_xcom_key, value=file_bytes) else: raise RuntimeError('The size of the downloaded file is too large to push to XCom!') self.log.info(file_bytes)