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.clients.consumer.internals.metrics;
  
  import org.apache.kafka.common.MetricName;
  import org.apache.kafka.common.metrics.Measurable;
  import org.apache.kafka.common.metrics.Metrics;
  import org.apache.kafka.common.metrics.Sensor;
  import org.apache.kafka.common.metrics.stats.Max;
  import org.apache.kafka.common.metrics.stats.Meter;
  import org.apache.kafka.common.metrics.stats.WindowedCount;
  
  import java.util.concurrent.TimeUnit;
  
  import static org.apache.kafka.clients.consumer.internals.ConsumerUtils.CONSUMER_METRIC_GROUP_PREFIX;
  import static org.apache.kafka.clients.consumer.internals.ConsumerUtils.COORDINATOR_METRICS_SUFFIX;
  
  public class HeartbeatMetricsManager {
      // MetricName visible for testing
      final MetricName heartbeatResponseTimeMax;
      final MetricName heartbeatRate;
      final MetricName heartbeatTotal;
      final MetricName lastHeartbeatSecondsAgo;
      private final Sensor heartbeatSensor;
      private long lastHeartbeatMs = -1L;
  
      public HeartbeatMetricsManager(Metrics metrics) {
          this(metrics, CONSUMER_METRIC_GROUP_PREFIX);
      }
  
      public HeartbeatMetricsManager(Metrics metrics, String metricGroupPrefix) {
          final String metricGroupName = metricGroupPrefix + COORDINATOR_METRICS_SUFFIX;
          heartbeatSensor = metrics.sensor("heartbeat-latency");
          heartbeatResponseTimeMax = metrics.metricName("heartbeat-response-time-max",
              metricGroupName,
              "The max time taken to receive a response to a heartbeat request");
          heartbeatSensor.add(heartbeatResponseTimeMax, new Max());
  
          // windowed meters
          heartbeatRate = metrics.metricName("heartbeat-rate", metricGroupName, "The number of heartbeats per second");
          heartbeatTotal = metrics.metricName("heartbeat-total", metricGroupName, "The total number of heartbeats");
          heartbeatSensor.add(new Meter(new WindowedCount(),
              heartbeatRate,
              heartbeatTotal));
  
          Measurable lastHeartbeat = (config, now) -> {
              final long lastHeartbeatSend = lastHeartbeatMs;
              if (lastHeartbeatSend < 0L)
                  // if no heartbeat is ever triggered, just return -1.
                  return -1d;
              else
                  return TimeUnit.SECONDS.convert(now - lastHeartbeatSend, TimeUnit.MILLISECONDS);
          };
          lastHeartbeatSecondsAgo = metrics.metricName("last-heartbeat-seconds-ago",
              metricGroupName,
              "The number of seconds since the last coordinator heartbeat was sent");
          metrics.addMetric(lastHeartbeatSecondsAgo, lastHeartbeat);
      }
  
      public void recordHeartbeatSentMs(long timeMs) {
          lastHeartbeatMs = timeMs;
      }
  
      public void recordRequestLatency(long requestLatencyMs) {
          heartbeatSensor.record(requestLatencyMs);
      }
  }
  