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.tools;
  
  import org.apache.kafka.clients.consumer.OffsetAndMetadata;
  import org.apache.kafka.common.TopicPartition;
  import org.apache.kafka.connect.errors.ConnectException;
  import org.apache.kafka.connect.sink.SinkRecord;
  import org.apache.kafka.connect.sink.SinkTask;
  
  import com.fasterxml.jackson.core.JsonProcessingException;
  import com.fasterxml.jackson.databind.ObjectMapper;
  
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  
  /**
   * Counterpart to {@link VerifiableSourceTask} that consumes records and logs information about each to stdout. This
   * allows validation of processing of messages by sink tasks on distributed workers even in the face of worker restarts
   * and failures. This task relies on the offset management provided by the Kafka Connect framework and therefore can detect
   * bugs in its implementation.
   */
  public class VerifiableSinkTask extends SinkTask {
      public static final String NAME_CONFIG = "name";
      public static final String ID_CONFIG = "id";
  
      private static final ObjectMapper JSON_SERDE = new ObjectMapper();
  
      private String name; // Connector name
      private int id; // Task ID
  
      private final Map<TopicPartition, List<Map<String, Object>>> unflushed = new HashMap<>();
  
      @Override
      public String version() {
          return new VerifiableSinkConnector().version();
      }
  
      @Override
      public void start(Map<String, String> props) {
          try {
              name = props.get(NAME_CONFIG);
              id = Integer.parseInt(props.get(ID_CONFIG));
          } catch (NumberFormatException e) {
              throw new ConnectException("Invalid VerifiableSourceTask configuration", e);
          }
      }
  
      @Override
      public void put(Collection<SinkRecord> records) {
          long nowMs = System.currentTimeMillis();
          for (SinkRecord record : records) {
              Map<String, Object> data = new HashMap<>();
              data.put("name", name);
              data.put("task", record.key()); // VerifiableSourceTask's input task (source partition)
              data.put("sinkTask", id);
              data.put("topic", record.topic());
              data.put("time_ms", nowMs);
              data.put("seqno", record.value());
              data.put("offset", record.kafkaOffset());
              String dataJson;
              try {
                  dataJson = JSON_SERDE.writeValueAsString(data);
              } catch (JsonProcessingException e) {
                  dataJson = "Bad data can't be written as json: " + e.getMessage();
              }
              System.out.println(dataJson);
              unflushed.computeIfAbsent(
                      new TopicPartition(record.topic(), record.kafkaPartition()),
                      tp -> new ArrayList<>()
              ).add(data);
          }
      }
  
      @Override
      public void flush(Map<TopicPartition, OffsetAndMetadata> offsets) {
          long nowMs = System.currentTimeMillis();
          for (TopicPartition topicPartition : offsets.keySet()) {
              if (!unflushed.containsKey(topicPartition)) {
                  continue;
              }
              for (Map<String, Object> data : unflushed.get(topicPartition)) {
                  data.put("time_ms", nowMs);
                  data.put("flushed", true);
                  String dataJson;
                  try {
                      dataJson = JSON_SERDE.writeValueAsString(data);
                  } catch (JsonProcessingException e) {
                      dataJson = "Bad data can't be written as json: " + e.getMessage();
                  }
                  System.out.println(dataJson);
              }
              unflushed.remove(topicPartition);
          }
      }
  
      @Override
      public void stop() {
  
      }
  }
  