Source code for airflow.providers.google.cloud.utils.bigquery_get_data

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from collections.abc import Iterator
from logging import Logger
from typing import List, Optional, Union

from google.cloud.bigquery.table import Row

from airflow.providers.google.cloud.hooks.bigquery import BigQueryHook


[docs]def bigquery_get_data(
    logger: Logger,
    dataset_id: str,
    table_id: str,
    big_query_hook: BigQueryHook,
    batch_size: int,
    selected_fields: Optional[Union[List[str], str]],
) -> Iterator:
    logger.info('Fetching Data from:')
    logger.info('Dataset: %s ; Table: %s', dataset_id, table_id)

    i = 0
    while True:
        rows: List[Row] = big_query_hook.list_rows(
            dataset_id=dataset_id,
            table_id=table_id,
            max_results=batch_size,
            selected_fields=selected_fields,
            start_index=i * batch_size,
        )

        if len(rows) == 0:
            logger.info('Job Finished')
            return

        logger.info('Total Extracted rows: %s', len(rows) + i * batch_size)

        yield [row.values() for row in rows]

        i += 1