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 static com.google.common.base.Preconditions.checkNotNull;
  import static org.apache.bookkeeper.stream.storage.StorageConstants.SERVERS_PATH;
  import static org.apache.bookkeeper.stream.storage.StorageConstants.ZK_METADATA_ROOT_PATH;
  
  import com.google.common.util.concurrent.ThreadFactoryBuilder;
  import java.io.IOException;
  import java.util.concurrent.Executors;
  import java.util.concurrent.ScheduledExecutorService;
  import java.util.function.Supplier;
  import lombok.SneakyThrows;
  import lombok.extern.slf4j.Slf4j;
  import org.apache.bookkeeper.common.component.AbstractLifecycleComponent;
  import org.apache.bookkeeper.conf.ClientConfiguration;
  import org.apache.bookkeeper.conf.ServerConfiguration;
  import org.apache.bookkeeper.discover.RegistrationClient;
  import org.apache.bookkeeper.discover.ZKRegistrationClient;
  import org.apache.bookkeeper.meta.zk.ZKMetadataDriverBase;
  import org.apache.bookkeeper.stats.StatsLogger;
  import org.apache.bookkeeper.stream.server.conf.DLConfiguration;
  import org.apache.bookkeeper.zookeeper.BoundExponentialBackoffRetryPolicy;
  import org.apache.bookkeeper.zookeeper.RetryPolicy;
  import org.apache.bookkeeper.zookeeper.ZooKeeperClient;
  
  /**
   * A service that is responsible for registration using bookkeeper registration api.
   */
  @Slf4j
  public class RegistrationServiceProvider
      extends AbstractLifecycleComponent<DLConfiguration>
      implements Supplier<RegistrationClient> {
  
      private final String zkServers;
      private final RetryPolicy bkZkRetryPolicy;
      private final String regPath;
      private final ScheduledExecutorService regExecutor;
      private final boolean bookieAddresschangeTracking;
      private ZooKeeperClient zkClient;
      private RegistrationClient client;
  
      public RegistrationServiceProvider(ServerConfiguration bkServerConf,
                                         DLConfiguration conf,
                                         StatsLogger statsLogger) {
          super("registration-service-provider", conf, statsLogger);
          this.zkServers = ZKMetadataDriverBase.resolveZkServers(bkServerConf);
          this.regPath = ZK_METADATA_ROOT_PATH + "/" + SERVERS_PATH;
          this.bkZkRetryPolicy = new BoundExponentialBackoffRetryPolicy(
              bkServerConf.getZkRetryBackoffStartMs(),
              bkServerConf.getZkRetryBackoffMaxMs(),
              bkServerConf.getZkRetryBackoffMaxRetries());
          this.regExecutor = Executors.newSingleThreadScheduledExecutor(
              new ThreadFactoryBuilder().setNameFormat("registration-service-provider-scheduler").build());
          ClientConfiguration clientConfiguration = new ClientConfiguration(bkServerConf);
          this.bookieAddresschangeTracking = clientConfiguration.getEnableBookieAddressTracking();
      }
  
      @Override
      public RegistrationClient get() {
          checkNotNull(client, "retrieve registration client before starting registration service");
          return client;
      }
  
      public ZooKeeperClient getZkClient() {
          return zkClient;
      }
  
      public String getRegistrationPath() {
          return regPath;
      }
  
      @SneakyThrows
      @Override
      protected void doStart() {
          if (null == zkClient) {
              try {
                  zkClient = ZooKeeperClient.newBuilder()
                      .operationRetryPolicy(bkZkRetryPolicy)
                      .connectString(zkServers)
                      .statsLogger(statsLogger.scope("zk"))
                      .build();
              } catch (InterruptedException e) {
                  Thread.currentThread().interrupt();
                  log.error("Interrupted at creating zookeeper client to {}", zkServers, e);
                  throw e;
              } catch (Exception e) {
                  log.error("Failed to create zookeeper client to {}", zkServers, e);
                  throw e;
              }
              client = new ZKRegistrationClient(zkClient, regPath, regExecutor, bookieAddresschangeTracking);
          }
      }
  
  
  
      @Override
      protected void doStop() {
      }
  
      @Override
      protected void doClose() throws IOException {
          if (null != client) {
              client.close();
          }
          if (null != zkClient) {
              try {
                  zkClient.close();
              } catch (InterruptedException e) {
                  Thread.currentThread().interrupt();
                  log.warn("Interrupted at closing zookeeper client to {}", zkServers, e);
              }
          }
          this.regExecutor.shutdown();
      }
  }
  