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.streams.internals.metrics;
  
  import org.apache.kafka.clients.consumer.Consumer;
  import org.apache.kafka.common.metrics.KafkaMetric;
  import org.apache.kafka.common.metrics.MetricsReporter;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.util.List;
  import java.util.Map;
  import java.util.Objects;
  import java.util.Optional;
  
  public class StreamsThreadMetricsDelegatingReporter implements MetricsReporter {
      
      private static final Logger log = LoggerFactory.getLogger(StreamsThreadMetricsDelegatingReporter.class);
      private static final String THREAD_ID_TAG = "thread-id";
      private final Consumer<byte[], byte[]> consumer;
      private final String threadId;
      private final Optional<String> stateUpdaterThreadId;
  
  
      public StreamsThreadMetricsDelegatingReporter(final Consumer<byte[], byte[]> consumer, final String threadId, final Optional<String> stateUpdaterThreadId) {
          this.consumer = Objects.requireNonNull(consumer);
          this.threadId = Objects.requireNonNull(threadId);
          this.stateUpdaterThreadId = stateUpdaterThreadId;
          log.debug("Creating MetricsReporter for threadId {} and stateUpdaterId {}", threadId, stateUpdaterThreadId);
      }
  
      @Override
      public void init(final List<KafkaMetric> metrics) {
          metrics.forEach(this::metricChange);
      }
  
      @Override
      public void metricChange(final KafkaMetric metric) {
          if (tagMatchStreamOrStateUpdaterThreadId(metric)) {
              log.debug("Registering metric {}", metric.metricName());
              consumer.registerMetricForSubscription(metric);
          }
      }
  
      private boolean tagMatchStreamOrStateUpdaterThreadId(final KafkaMetric metric) {
          final Map<String, String> tags = metric.metricName().tags();
          final boolean shouldInclude = tags.containsKey(THREAD_ID_TAG) && (tags.get(THREAD_ID_TAG).equals(threadId) ||
                  Optional.ofNullable(tags.get(THREAD_ID_TAG)).equals(stateUpdaterThreadId));
          if (!shouldInclude) {
              log.trace("Rejecting metric {}", metric.metricName());
          }
          return shouldInclude;
      }
  
      @Override
      public void metricRemoval(final KafkaMetric metric) {
          if (tagMatchStreamOrStateUpdaterThreadId(metric)) {
              log.debug("Unregistering metric {}", metric.metricName());
              consumer.unregisterMetricFromSubscription(metric);
          }
      }
  
      @Override
      public void close() {
          // No op
      }
  
      @Override
      public void configure(final Map<String, ?> configs) {
          // No op
      }
  }
  