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"""This module contains Google BigQuery to Google Cloud Storage operator."""
import warnings
from typing import Any, Dict, List, Optional, Sequence, Union
from google.cloud.bigquery.table import TableReference
from airflow.models import BaseOperator
from airflow.providers.google.cloud.hooks.bigquery import BigQueryHook
[docs]class BigQueryToGCSOperator(BaseOperator):
"""
Transfers a BigQuery table to a Google Cloud Storage bucket.
.. seealso::
For more details about these parameters:
https://cloud.google.com/bigquery/docs/reference/v2/jobs
:param source_project_dataset_table: The dotted
``(<project>.|<project>:)<dataset>.<table>`` BigQuery table to use as the
source data. If ``<project>`` is not included, project will be the project
defined in the connection json. (templated)
:type source_project_dataset_table: str
:param destination_cloud_storage_uris: The destination Google Cloud
Storage URI (e.g. gs://some-bucket/some-file.txt). (templated) Follows
convention defined here:
https://cloud.google.com/bigquery/exporting-data-from-bigquery#exportingmultiple
:type destination_cloud_storage_uris: List[str]
:param compression: Type of compression to use.
:type compression: str
:param export_format: File format to export.
:type export_format: str
:param field_delimiter: The delimiter to use when extracting to a CSV.
:type field_delimiter: str
:param print_header: Whether to print a header for a CSV file extract.
:type print_header: bool
:param gcp_conn_id: (Optional) The connection ID used to connect to Google Cloud.
:type gcp_conn_id: str
:param bigquery_conn_id: (Deprecated) The connection ID used to connect to Google Cloud.
This parameter has been deprecated. You should pass the gcp_conn_id parameter instead.
:type bigquery_conn_id: str
:param delegate_to: The account to impersonate using domain-wide delegation of authority,
if any. For this to work, the service account making the request must have
domain-wide delegation enabled.
:type delegate_to: str
:param labels: a dictionary containing labels for the job/query,
passed to BigQuery
:type labels: dict
:param location: The location used for the operation.
:type location: str
:param impersonation_chain: Optional service account to impersonate using short-term
credentials, or chained list of accounts required to get the access_token
of the last account in the list, which will be impersonated in the request.
If set as a string, the account must grant the originating account
the Service Account Token Creator IAM role.
If set as a sequence, the identities from the list must grant
Service Account Token Creator IAM role to the directly preceding identity, with first
account from the list granting this role to the originating account (templated).
:type impersonation_chain: Union[str, Sequence[str]]
"""
[docs] template_fields = (
'source_project_dataset_table',
'destination_cloud_storage_uris',
'labels',
'impersonation_chain',
)
def __init__(
self,
*,
source_project_dataset_table: str,
destination_cloud_storage_uris: List[str],
compression: str = 'NONE',
export_format: str = 'CSV',
field_delimiter: str = ',',
print_header: bool = True,
gcp_conn_id: str = 'google_cloud_default',
bigquery_conn_id: Optional[str] = None,
delegate_to: Optional[str] = None,
labels: Optional[Dict] = None,
location: Optional[str] = None,
impersonation_chain: Optional[Union[str, Sequence[str]]] = None,
**kwargs,
) -> None:
super().__init__(**kwargs)
if bigquery_conn_id:
warnings.warn(
"The bigquery_conn_id parameter has been deprecated. You should pass "
"the gcp_conn_id parameter.",
DeprecationWarning,
stacklevel=3,
)
gcp_conn_id = bigquery_conn_id
self.source_project_dataset_table = source_project_dataset_table
self.destination_cloud_storage_uris = destination_cloud_storage_uris
self.compression = compression
self.export_format = export_format
self.field_delimiter = field_delimiter
self.print_header = print_header
self.gcp_conn_id = gcp_conn_id
self.delegate_to = delegate_to
self.labels = labels
self.location = location
self.impersonation_chain = impersonation_chain
[docs] def execute(self, context):
self.log.info(
'Executing extract of %s into: %s',
self.source_project_dataset_table,
self.destination_cloud_storage_uris,
)
hook = BigQueryHook(
bigquery_conn_id=self.gcp_conn_id,
delegate_to=self.delegate_to,
location=self.location,
impersonation_chain=self.impersonation_chain,
)
table_ref = TableReference.from_string(self.source_project_dataset_table, hook.project_id)
configuration: Dict[str, Any] = {
'extract': {
'sourceTable': table_ref.to_api_repr(),
'compression': self.compression,
'destinationUris': self.destination_cloud_storage_uris,
'destinationFormat': self.export_format,
}
}
if self.labels:
configuration['labels'] = self.labels
if self.export_format == 'CSV':
# Only set fieldDelimiter and printHeader fields if using CSV.
# Google does not like it if you set these fields for other export
# formats.
configuration['extract']['fieldDelimiter'] = self.field_delimiter
configuration['extract']['printHeader'] = self.print_header
hook.insert_job(configuration=configuration)