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.bookkeeper.stream.server.service;
  
  import java.io.IOException;
  import java.util.function.Supplier;
  import lombok.extern.slf4j.Slf4j;
  import org.apache.bookkeeper.common.component.AbstractLifecycleComponent;
  import org.apache.bookkeeper.conf.ServerConfiguration;
  import org.apache.bookkeeper.meta.zk.ZKMetadataDriverBase;
  import org.apache.bookkeeper.stats.StatsLogger;
  import org.apache.bookkeeper.stream.server.conf.DLConfiguration;
  import org.apache.curator.RetryPolicy;
  import org.apache.curator.framework.CuratorFramework;
  import org.apache.curator.framework.CuratorFrameworkFactory;
  import org.apache.curator.retry.ExponentialBackoffRetry;
  
  /**
   * A service to provide a curator client.
   */
  @Slf4j
  public class CuratorProviderService
      extends AbstractLifecycleComponent<DLConfiguration>
      implements Supplier<CuratorFramework> {
  
      private final String zkServers;
      private final RetryPolicy curatorRetryPolicy;
      private final CuratorFramework curatorClient;
  
      public CuratorProviderService(ServerConfiguration bkServerConf,
                                    DLConfiguration conf,
                                    StatsLogger statsLogger) {
          super("curator-provider", conf, statsLogger);
          this.zkServers = ZKMetadataDriverBase.resolveZkServers(bkServerConf);
          this.curatorRetryPolicy = new ExponentialBackoffRetry(
              bkServerConf.getZkRetryBackoffStartMs(),
              Integer.MAX_VALUE,
              bkServerConf.getZkRetryBackoffMaxMs());
          this.curatorClient = CuratorFrameworkFactory
              .newClient(zkServers, curatorRetryPolicy);
      }
  
      @Override
      protected void doStart() {
          curatorClient.start();
          log.info("Provided curator clients to zookeeper {}.", zkServers);
      }
  
      @Override
      protected void doStop() {
      }
  
      @Override
      protected void doClose() throws IOException {
          curatorClient.close();
      }
  
      @Override
      public CuratorFramework get() {
          return curatorClient;
      }
  }
  