Source code for airflow.providers.google.cloud.utils.bigquery_get_data
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from __future__ import annotations
import itertools
from typing import TYPE_CHECKING
from google.cloud.bigquery.table import Row, RowIterator
if TYPE_CHECKING:
from collections.abc import Iterator
from logging import Logger
from airflow.providers.google.cloud.hooks.bigquery import BigQueryHook
[docs]def bigquery_get_data(
logger: Logger,
dataset_id: str | None,
table_id: str | None,
big_query_hook: BigQueryHook,
batch_size: int,
selected_fields: list[str] | str | None,
) -> Iterator:
logger.info("Fetching Data from:")
logger.info("Dataset: %s ; Table: %s", dataset_id, table_id)
for start_index in itertools.count(step=batch_size):
rows: list[Row] | RowIterator = big_query_hook.list_rows(
dataset_id=dataset_id,
table_id=table_id,
max_results=batch_size,
selected_fields=selected_fields,
start_index=start_index,
)
if isinstance(rows, RowIterator):
raise TypeError("BigQueryHook.list_rows() returns iterator when return_iterator=False (default)")
if len(rows) == 0:
logger.info("Job Finished")
return
logger.info("Total Extracted rows: %s", len(rows) + start_index)
yield [row.values() for row in rows]