使用代码，如何更新气流变量？

编程入门行业动态更新时间:2024-10-27 04:35:48

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我需要以编程方式更新在Airflow中创建的变量，但找不到如何使用代码来解决问题的答案。

I need to update a variable I have made in Airflow programmatically but I can not find the answer on how to do that with code.

我已检索到变量使用以下代码：

I have retrieved my variable with this code:

column_number = Variable.get（'column_number'）

在函数末尾，我想将column_number加1

At the end of the function, I would like to increment the column_number by one

我已经尝试过： Variable.set_val（ column_number，int（column_number）+ 1）

它不起作用。

以下是完整的参考代码：

Here is the full code for reference:

import airflow from datetime import datetime, timedelta from random import randint from airflow import DAG from airflow.hooks.postgres_hook import PostgresHook from airflow.models import Variable from airflow.operators.python_operator import PythonOperator args = { 'owner': 'besteman', 'start_date': datetime.utcnow(), 'retries': 1, 'retry_delay': timedelta(minutes=30) } dag = DAG(dag_id='test-postgres', default_args=args, schedule_interval='@hourly') def add_columns_and_values(): column_number = Variable.get('column_number') pg_hook = PostgresHook(postgres_conn_id='airflow-test') add_columns = f'ALTER TABLE students ADD COLUMN test{column_number} smallint;' pg_hook.run(add_columns) for i in range(8): add_values = f"UPDATE students SET test{column_number} = '{randint(50, 100)}' WHERE id = {i+1};" pg_hook.run(add_values) Variable.set_val("column_number", int(column_number) + 1) t1 = PythonOperator(task_id='add_columns_values', python_callable=add_columns_and_values, dag=dag)

推荐答案

使用 Variable.set 代替 Variable.set_val 。 set_val（）是 val 属性的设置器，不适用于外部使用。这应该做您想要的：

Use Variable.set instead of Variable.set_val. set_val() is a setter for the val attribute and not intended for outside use. This should do what you want:

Variable.set("column_number", int(column_number) + 1)

它将对数据库进行实际更新，并在需要时为您处理会话和序列化。

It will make the actual update to the database, along with handling session and serialization for you if needed.