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.kafka.connect.mirror;
  
  import org.apache.kafka.clients.admin.Admin;
  import org.apache.kafka.common.config.ConfigDef;
  import org.apache.kafka.common.utils.AppInfoParser;
  import org.apache.kafka.common.utils.Utils;
  import org.apache.kafka.connect.connector.Task;
  import org.apache.kafka.connect.errors.ConnectException;
  import org.apache.kafka.connect.source.SourceConnector;
  
  import java.util.Collections;
  import java.util.List;
  import java.util.Map;
  
  import static org.apache.kafka.connect.mirror.Heartbeat.SOURCE_CLUSTER_ALIAS_KEY;
  import static org.apache.kafka.connect.mirror.Heartbeat.TARGET_CLUSTER_ALIAS_KEY;
  
  /** Emits heartbeats to Kafka.
   *
   *  @see MirrorHeartbeatConfig for supported config properties.
   */
  public class MirrorHeartbeatConnector extends SourceConnector {
      private MirrorHeartbeatConfig config;
      private Scheduler scheduler;
      private Admin targetAdminClient;
  
      public MirrorHeartbeatConnector() {
          // nop
      }
  
      // visible for testing
      MirrorHeartbeatConnector(MirrorHeartbeatConfig config) {
          this.config = config;
      }
  
      @Override
      public void start(Map<String, String> props) {
          config = new MirrorHeartbeatConfig(props);
          targetAdminClient = config.forwardingAdmin(config.targetAdminConfig("heartbeats-target-admin"));
          scheduler = new Scheduler(getClass(), config.entityLabel(), config.adminTimeout());
          scheduler.execute(this::createInternalTopics, "creating internal topics");
      }
  
      @Override
      public void stop() {
          Utils.closeQuietly(scheduler, "scheduler");
          Utils.closeQuietly(targetAdminClient, "target admin client");
      }
  
      @Override
      public Class<? extends Task> taskClass() {
          return MirrorHeartbeatTask.class;
      }
  
      @Override
      public List<Map<String, String>> taskConfigs(int maxTasks) {
          // if the heartbeats emission is disabled by setting `emit.heartbeats.enabled` to `false`,
          // the interval heartbeat emission will be negative and no `MirrorHeartbeatTask` will be created
          if (config.emitHeartbeatsInterval().isNegative()) {
              return Collections.emptyList();
          }
          // just need a single task
          return Collections.singletonList(config.originalsStrings());
      }
  
      @Override
      public ConfigDef config() {
          return MirrorHeartbeatConfig.CONNECTOR_CONFIG_DEF;
      }
  
      @Override
      public String version() {
          return AppInfoParser.getVersion();
      }
  
      @Override
      public boolean alterOffsets(Map<String, String> config, Map<Map<String, ?>, Map<String, ?>> offsets) {
          for (Map.Entry<Map<String, ?>, Map<String, ?>> offsetEntry : offsets.entrySet()) {
              Map<String, ?> sourceOffset = offsetEntry.getValue();
              if (sourceOffset == null) {
                  // We allow tombstones for anything; if there's garbage in the offsets for the connector, we don't
                  // want to prevent users from being able to clean it up using the REST API
                  continue;
              }
  
              Map<String, ?> sourcePartition = offsetEntry.getKey();
              if (sourcePartition == null) {
                  throw new ConnectException("Source partitions may not be null");
              }
  
              MirrorUtils.validateSourcePartitionString(sourcePartition, SOURCE_CLUSTER_ALIAS_KEY);
              MirrorUtils.validateSourcePartitionString(sourcePartition, TARGET_CLUSTER_ALIAS_KEY);
  
              MirrorUtils.validateSourceOffset(sourcePartition, sourceOffset, true);
          }
  
          // We don't actually use these offsets in the task class, so no additional effort is required beyond just validating
          // the format of the user-supplied offsets
          return true;
      }
  
      private void createInternalTopics() {
          MirrorUtils.createSinglePartitionCompactedTopic(
                  config.heartbeatsTopic(),
                  config.heartbeatsTopicReplicationFactor(),
                  targetAdminClient
          );
      }
  }
  