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.server.http.service;
  
  import java.util.Iterator;
  import lombok.AllArgsConstructor;
  import lombok.Data;
  import lombok.NonNull;
  import lombok.SneakyThrows;
  import lombok.extern.slf4j.Slf4j;
  import org.apache.bookkeeper.client.BookKeeperAdmin;
  import org.apache.bookkeeper.common.util.JsonUtil;
  import org.apache.bookkeeper.http.HttpServer;
  import org.apache.bookkeeper.http.service.HttpEndpointService;
  import org.apache.bookkeeper.http.service.HttpServiceRequest;
  import org.apache.bookkeeper.http.service.HttpServiceResponse;
  import org.apache.bookkeeper.meta.LedgerManagerFactory;
  import org.apache.bookkeeper.meta.LedgerUnderreplicationManager;
  import org.apache.bookkeeper.meta.UnderreplicatedLedger;
  import org.apache.bookkeeper.net.BookieId;
  
  /**
   * HttpEndpointService that exposes the current info about the cluster of bookies.
   *
   * <pre>
   * <code>
   * {
   *  "hasAuditorElected" : true,
   *  "auditorId" : "blah",
   *  "hasUnderReplicatedLedgers": false,
   *  "isLedgerReplicationEnabled": true,
   *  "totalBookiesCount": 10,
   *  "writableBookiesCount": 6,
   *  "readonlyBookiesCount": 3,
   *  "unavailableBookiesCount": 1
   * }
   * </code>
   * </pre>
   */
  @AllArgsConstructor
  @Slf4j
  public class ClusterInfoService implements HttpEndpointService {
  
      @NonNull
      private final BookKeeperAdmin bka;
      @NonNull
      private final LedgerManagerFactory ledgerManagerFactory;
  
      /**
       * POJO definition for the cluster info response.
       */
      @Data
      public static class ClusterInfo {
          private boolean auditorElected;
          private String auditorId;
          private boolean clusterUnderReplicated;
          private boolean ledgerReplicationEnabled;
          private int totalBookiesCount;
          private int writableBookiesCount;
          private int readonlyBookiesCount;
          private int unavailableBookiesCount;
      }
  
      @Override
      public HttpServiceResponse handle(HttpServiceRequest request) throws Exception {
          final HttpServiceResponse response = new HttpServiceResponse();
  
          if (HttpServer.Method.GET != request.getMethod()) {
              response.setCode(HttpServer.StatusCode.NOT_FOUND);
              response.setBody("Only GET is supported.");
              return response;
          }
  
          final ClusterInfo info = new ClusterInfo();
          fillUReplicatedInfo(info);
          fillAuditorInfo(info);
          fillBookiesInfo(info);
  
          String jsonResponse = JsonUtil.toJson(info);
          response.setBody(jsonResponse);
          response.setCode(HttpServer.StatusCode.OK);
          return response;
      }
  
      @SneakyThrows
      private void fillBookiesInfo(ClusterInfo info) {
          int totalBookiesCount = bka.getAllBookies().size();
          int writableBookiesCount = bka.getAvailableBookies().size();
          int readonlyBookiesCount = bka.getReadOnlyBookies().size();
          int unavailableBookiesCount = totalBookiesCount - writableBookiesCount - readonlyBookiesCount;
  
          info.setTotalBookiesCount(totalBookiesCount);
          info.setWritableBookiesCount(writableBookiesCount);
          info.setReadonlyBookiesCount(readonlyBookiesCount);
          info.setUnavailableBookiesCount(unavailableBookiesCount);
      }
  
      private void fillAuditorInfo(ClusterInfo info) {
          try {
              BookieId currentAuditor = bka.getCurrentAuditor();
              info.setAuditorElected(currentAuditor != null);
              info.setAuditorId(currentAuditor == null ? "" : currentAuditor.getId());
          } catch (Exception e) {
              log.error("Could not get Auditor info", e);
              info.setAuditorElected(false);
              info.setAuditorId("");
          }
      }
  
      @SneakyThrows
      private void fillUReplicatedInfo(ClusterInfo info) {
          try (LedgerUnderreplicationManager underreplicationManager =
                  ledgerManagerFactory.newLedgerUnderreplicationManager()) {
              Iterator<UnderreplicatedLedger> iter = underreplicationManager.listLedgersToRereplicate(null);
  
              info.setClusterUnderReplicated(iter.hasNext());
              info.setLedgerReplicationEnabled(underreplicationManager.isLedgerReplicationEnabled());
          }
      }
  
  }
  