jbbqqf commented on code in PR #30658: URL: https://github.com/apache/airflow/pull/30658#discussion_r1181496027
########## airflow/providers/google/cloud/transfers/bigquery_to_sql.py: ########## @@ -0,0 +1,126 @@ +# +# Licensed to the Apache Software Foundation (ASF) under one +# or more contributor license agreements. See the NOTICE file +# distributed with this work for additional information +# regarding copyright ownership. The ASF licenses this file +# to you under the Apache License, Version 2.0 (the +# "License"); you may not use this file except in compliance +# with the License. You may obtain a copy of the License at +# +# http://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, +# software distributed under the License is distributed on an +# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +# KIND, either express or implied. See the License for the +# specific language governing permissions and limitations +# under the License. +"""Base operator for BigQuery to SQL operators.""" +from __future__ import annotations + +import abc +from typing import TYPE_CHECKING, Sequence + +from airflow.models import BaseOperator +from airflow.providers.common.sql.hooks.sql import DbApiHook +from airflow.providers.google.cloud.hooks.bigquery import BigQueryHook +from airflow.providers.google.cloud.utils.bigquery_get_data import bigquery_get_data + +if TYPE_CHECKING: + from airflow.utils.context import Context + + +class BaseBigQueryToSqlOperator(BaseOperator): + """ + Fetches the data from a BigQuery table (alternatively fetch data for selected columns) + and insert that data into a SQL table. + + .. note:: + If you pass fields to ``selected_fields`` which are in different order than the + order of columns already in + BQ table, the data will still be in the order of BQ table. + For example if the BQ table has 3 columns as + ``[A,B,C]`` and you pass 'B,A' in the ``selected_fields`` + the data would still be of the form ``'A,B'`` and passed through this form + to the SQL database. + + :param dataset_table: A dotted ``<dataset>.<table>``: the big query table of origin + :param selected_fields: List of fields to return (comma-separated). If + unspecified, all fields are returned. + :param gcp_conn_id: reference to a specific Google Cloud hook. + :param database: name of database which overwrite defined one in connection + :param replace: Whether to replace instead of insert + :param batch_size: The number of rows to take in each batch + :param location: The location used for the operation. + :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). + """ + + template_fields: Sequence[str] = ( + "sql_table", + "impersonation_chain", + ) + + def __init__( + self, + *, + dataset_table: str, + sql_table: str, + selected_fields: list[str] | str | None = None, + gcp_conn_id: str = "google_cloud_default", + database: str | None = None, + replace: bool = False, + batch_size: int = 1000, + location: str | None = None, + impersonation_chain: str | Sequence[str] | None = None, + **kwargs, + ) -> None: + super().__init__(**kwargs) + self.selected_fields = selected_fields + self.gcp_conn_id = gcp_conn_id + self.database = database + self.sql_table = sql_table + self.replace = replace + self.batch_size = batch_size + self.location = location + self.impersonation_chain = impersonation_chain + try: + self.dataset_id, self.table_id = dataset_table.split(".") + except ValueError: + raise ValueError(f"Could not parse {dataset_table} as <dataset>.<table>") from None + + @abc.abstractmethod + def get_sql_hook(self) -> DbApiHook: + pass Review Comment: > Public methods (including the __init__ constructor) should also have docstrings. The wording of PEP 257 implies it's optional. In Clean Code, Robert Martin enumerates a collection of smells and heuristics including: > C3: Redundant Comment > > A comment is redundant if it describes something that adequately describes itself. For example: > i++; // increment i > > Another example is a Javadoc that says nothing more than (or even less than) the function signature. > > Comments should say things that the code cannot say for itself. As suggested, I put my opinion aside and described `persist_links` with `"""This function persists the connection to the SQL provider"""`. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
