text: # 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.
  """
  Classes for interacting with Kubernetes API.
  """
  from abc import ABC, abstractmethod
  from functools import reduce
  from typing import List, Optional
  
  from kubernetes.client import models as k8s
  
  
  class K8SModel(ABC):
      """
      These Airflow Kubernetes models are here for backwards compatibility
      reasons only. Ideally clients should use the kubernetes api
      and the process of
  
          client input -> Airflow k8s models -> k8s models
  
      can be avoided. All of these models implement the
      `attach_to_pod` method so that they integrate with the kubernetes client.
      """
  
      @abstractmethod
      def attach_to_pod(self, pod: k8s.V1Pod) -> k8s.V1Pod:
          """
          :param pod: A pod to attach this Kubernetes object to
          :type pod: kubernetes.client.models.V1Pod
          :return: The pod with the object attached
          """
  
  
  def append_to_pod(pod: k8s.V1Pod, k8s_objects: Optional[List[K8SModel]]):
      """
      :param pod: A pod to attach a list of Kubernetes objects to
      :type pod: kubernetes.client.models.V1Pod
      :param k8s_objects: a potential None list of K8SModels
      :type k8s_objects: Optional[List[K8SModel]]
      :return: pod with the objects attached if they exist
      """
      if not k8s_objects:
          return pod
      return reduce(lambda p, o: o.attach_to_pod(p), k8s_objects, pod)
  