如何在ApacheAirflow中运行BigQuery查询，然后将输出的CSV发送到Google Cloud Storage？

How to run a BigQuery query and then send the output CSV to Google Cloud Storage in Apache Airflow?(如何在ApacheAirflow中运行BigQuery查询，然后将输出的CSV发送到Google Cloud Storage？)

问题描述

我需要在python中运行一个BigQuery脚本，它需要在Google云存储中作为CSV输出。目前，我的脚本触发大查询代码，直接保存到我的PC上。

但是，我需要让它在气流中运行，这样我就不能有任何本地依赖项。

我当前的脚本将输出保存到本地计算机，然后我必须将其移到GCS中。我在网上查过了，但我想不通。(PS我还是个新手，所以如果以前有人问过这个问题，我很抱歉！)

import pandas as pd
from googleapiclient import discovery
from oauth2client.client import GoogleCredentials

def run_script():

    df = pd.read_gbq('SELECT * FROM `table/veiw` LIMIT 15000',
                 project_id='PROJECT',
                 dialect='standard'
                 )

    df.to_csv('XXX.csv', index=False)

def copy_to_gcs(filename, bucket, destination_filename):

    credentials = GoogleCredentials.get_application_default()
    service = discovery.build('storage', 'v1', credentials=credentials)

    body = {'name': destination_filename}
    req = service.objects().insert(bucket=bucket,body=body, media_body=filename)
    resp = req.execute()

current_date = datetime.date.today()
filename = (r"C:UsersLOCALDRIVEETCETCETC.csv")
bucket = 'My GCS BUCKET'

str_prefix_datetime = datetime.datetime.now().strftime('%Y%m%d_%H%M%S')
destfile = 'XXX' + str_prefix_datetime + '.csv'
print('')

    ```

推荐答案

Airflow为使用BigQuery提供了几个运算符。

• BigQueryOperator对BigQuery执行查询。
• BigQueryToCloudStorageOperator将BigQuery表导出到GCS。

您可以看到一个运行查询的示例，后跟exporting the results to a CSV in the Cloud Composer code samples。

# Copyright 2018 Google LLC
#
# Licensed 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
#
#     https://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.
# Query recent StackOverflow questions.

bq_recent_questions_query = bigquery_operator.BigQueryOperator(
    task_id='bq_recent_questions_query',
    sql="""
    SELECT owner_display_name, title, view_count
    FROM `bigquery-public-data.stackoverflow.posts_questions`
    WHERE creation_date < CAST('{max_date}' AS TIMESTAMP)
        AND creation_date >= CAST('{min_date}' AS TIMESTAMP)
    ORDER BY view_count DESC
    LIMIT 100
    """.format(max_date=max_query_date, min_date=min_query_date),
    use_legacy_sql=False,
    destination_dataset_table=bq_recent_questions_table_id)

# Export query result to Cloud Storage.
export_questions_to_gcs = bigquery_to_gcs.BigQueryToCloudStorageOperator(
    task_id='export_recent_questions_to_gcs',
    source_project_dataset_table=bq_recent_questions_table_id,
    destination_cloud_storage_uris=[output_file],
    export_format='CSV')

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