text: # -*- coding: utf-8 -*-
  #
  # 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.
  
  import random
  
  import airflow
  from airflow.models import DAG
  from airflow.operators.dummy_operator import DummyOperator
  from airflow.operators.python_operator import BranchPythonOperator
  
  args = {
      'owner': 'airflow',
      'start_date': airflow.utils.dates.days_ago(2),
  }
  
  dag = DAG(
      dag_id='example_branch_operator',
      default_args=args,
      schedule_interval="@daily",
  )
  
  run_this_first = DummyOperator(
      task_id='run_this_first',
      dag=dag,
  )
  
  options = ['branch_a', 'branch_b', 'branch_c', 'branch_d']
  
  # 创建一个分支选择器，随机选择一条分支执行，其他的分支忽略
  branching = BranchPythonOperator(
      task_id='branching',
      python_callable=lambda: random.choice(options),
      dag=dag,
  )
  run_this_first >> branching
  
  # 合并规则：只要有一条分支成功，则执行
  join = DummyOperator(
      task_id='join',
      trigger_rule='one_success',
      dag=dag,
  )
  
  for option in options:
      t = DummyOperator(
          task_id=option,
          dag=dag,
      )
  
      dummy_follow = DummyOperator(
          task_id='follow_' + option,
          dag=dag,
      )
  
      branching >> t >> dummy_follow >> join
  