content: /*
   * 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.
   */
  
  package org.apache.spark.shuffle.celeborn;
  
  import org.apache.spark.ShuffleDependency;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import org.apache.celeborn.client.LifecycleManager;
  import org.apache.celeborn.common.CelebornConf;
  
  public class WorkersAvailableFallbackPolicy implements ShuffleFallbackPolicy {
  
    private static final Logger LOG = LoggerFactory.getLogger(WorkersAvailableFallbackPolicy.class);
  
    public static final WorkersAvailableFallbackPolicy INSTANCE =
        new WorkersAvailableFallbackPolicy();
  
    /**
     * If celeborn cluster has no available workers, fallback to spark built-in shuffle
     * implementation.
     *
     * @param shuffleDependency The shuffle dependency of Spark.
     * @param celebornConf The configuration of Celeborn.
     * @param lifecycleManager The {@link LifecycleManager} of Celeborn.
     * @return Whether celeborn cluster has no available workers.
     */
    @Override
    public boolean needFallback(
        ShuffleDependency<?, ?, ?> shuffleDependency,
        CelebornConf celebornConf,
        LifecycleManager lifecycleManager) {
      if (!celebornConf.checkWorkerEnabled()) {
        return false;
      }
      boolean needFallback = !lifecycleManager.checkWorkersAvailable().getAvailable();
      if (needFallback) {
        LOG.warn(
            "No celeborn workers available for current user {}.",
            lifecycleManager.getUserIdentifier());
      }
      return needFallback;
    }
  }
  