code: /*
   * 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.skywalking.oap.server.analyzer.agent.kafka.provider.handler;
  
  import com.google.protobuf.InvalidProtocolBufferException;
  import lombok.extern.slf4j.Slf4j;
  import org.apache.kafka.clients.consumer.ConsumerRecord;
  import org.apache.kafka.common.utils.Bytes;
  import org.apache.skywalking.apm.network.language.agent.v3.SegmentObject;
  import org.apache.skywalking.oap.server.analyzer.agent.kafka.module.KafkaFetcherConfig;
  import org.apache.skywalking.oap.server.analyzer.module.AnalyzerModule;
  import org.apache.skywalking.oap.server.analyzer.provider.trace.parser.ISegmentParserService;
  import org.apache.skywalking.oap.server.library.module.ModuleManager;
  import org.apache.skywalking.oap.server.telemetry.TelemetryModule;
  import org.apache.skywalking.oap.server.telemetry.api.CounterMetrics;
  import org.apache.skywalking.oap.server.telemetry.api.HistogramMetrics;
  import org.apache.skywalking.oap.server.telemetry.api.MetricsCreator;
  import org.apache.skywalking.oap.server.telemetry.api.MetricsTag;
  
  /**
   * A handler deserializes the message of the trace segment data and pushes it to downstream.
   */
  @Slf4j
  public class TraceSegmentHandler extends AbstractKafkaHandler {
  
      private final ISegmentParserService segmentParserService;
  
      private final HistogramMetrics histogram;
      private final CounterMetrics errorCounter;
  
      public TraceSegmentHandler(ModuleManager moduleManager, KafkaFetcherConfig config) {
          super(moduleManager, config);
          this.segmentParserService = moduleManager.find(AnalyzerModule.NAME)
                                                   .provider()
                                                   .getService(ISegmentParserService.class);
  
          MetricsCreator metricsCreator = moduleManager.find(TelemetryModule.NAME)
                                                       .provider().getService(MetricsCreator.class);
  
          histogram = metricsCreator.createHistogramMetric(
              "trace_in_latency",
              "The process latency of trace data",
              new MetricsTag.Keys("protocol"),
              new MetricsTag.Values("kafka")
          );
          errorCounter = metricsCreator.createCounter(
              "trace_analysis_error_count",
              "The error number of trace analysis",
              new MetricsTag.Keys("protocol"),
              new MetricsTag.Values("kafka")
          );
      }
  
      @Override
      public void handle(final ConsumerRecord<String, Bytes> record) {
          try (HistogramMetrics.Timer ignored = histogram.createTimer()) {
              SegmentObject segment = SegmentObject.parseFrom(record.value().get());
              if (log.isDebugEnabled()) {
                  log.debug(
                      "Fetched a tracing segment[{}] from service instance[{}].",
                      segment.getTraceSegmentId(),
                      segment.getServiceInstance()
                  );
              }
              segmentParserService.send(segment);
          } catch (InvalidProtocolBufferException e) {
              errorCounter.inc();
              log.error("handle record failed", e);
          }
      }
  
      @Override
      protected String getPlainTopic() {
          return config.getTopicNameOfTracingSegments();
      }
  }
  