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.server.share.metrics;
  
  import org.apache.kafka.common.utils.Utils;
  import org.apache.kafka.server.metrics.KafkaMetricsGroup;
  
  import com.yammer.metrics.core.Histogram;
  import com.yammer.metrics.core.Meter;
  
  import java.util.List;
  import java.util.Map;
  import java.util.Objects;
  import java.util.concurrent.TimeUnit;
  import java.util.function.Supplier;
  
  /**
   * SharePartitionMetrics is used to track the broker-side metrics for the SharePartition.
   */
  public class SharePartitionMetrics implements AutoCloseable {
  
      public static final String IN_FLIGHT_MESSAGE_COUNT = "InFlightMessageCount";
      public static final String IN_FLIGHT_BATCH_COUNT = "InFlightBatchCount";
  
      private static final String ACQUISITION_LOCK_TIMEOUT_PER_SEC = "AcquisitionLockTimeoutPerSec";
      private static final String IN_FLIGHT_BATCH_MESSAGE_COUNT = "InFlightBatchMessageCount";
      private static final String FETCH_LOCK_TIME_MS = "FetchLockTimeMs";
      private static final String FETCH_LOCK_RATIO = "FetchLockRatio";
  
      /**
       * Metric for the rate of acquisition lock timeouts for records.
       */
      private final Meter acquisitionLockTimeoutPerSec;
      /**
       * Metric for the number of in-flight messages for the batch.
       */
      private final Histogram inFlightBatchMessageCount;
      /**
       * Metric for the time the fetch lock is held.
       */
      private final Histogram fetchLockTimeMs;
      /**
       * Metric for the ratio of fetch lock time to the total time.
       */
      private final Histogram fetchLockRatio;
  
      private final Map<String, String> tags;
      private final KafkaMetricsGroup metricsGroup;
  
      public SharePartitionMetrics(String groupId, String topic, int partition) {
          this.tags = Utils.mkMap(
              Utils.mkEntry("group", Objects.requireNonNull(groupId)),
              Utils.mkEntry("topic", Objects.requireNonNull(topic)),
              Utils.mkEntry("partition", String.valueOf(partition))
          );
          this.metricsGroup = new KafkaMetricsGroup("kafka.server", "SharePartitionMetrics");
  
          this.acquisitionLockTimeoutPerSec = metricsGroup.newMeter(
              ACQUISITION_LOCK_TIMEOUT_PER_SEC,
              "acquisition lock timeout",
              TimeUnit.SECONDS,
              this.tags);
  
          this.inFlightBatchMessageCount = metricsGroup.newHistogram(
              IN_FLIGHT_BATCH_MESSAGE_COUNT,
              true,
              this.tags);
  
          this.fetchLockTimeMs = metricsGroup.newHistogram(
              FETCH_LOCK_TIME_MS,
              true,
              this.tags);
  
          this.fetchLockRatio = metricsGroup.newHistogram(
              FETCH_LOCK_RATIO,
              true,
              this.tags);
      }
  
      /**
       * Register a gauge for the in-flight message count.
       *
       * @param messageCountSupplier The supplier for the in-flight message count.
       */
      public void registerInFlightMessageCount(Supplier<Long> messageCountSupplier) {
          metricsGroup.newGauge(
              IN_FLIGHT_MESSAGE_COUNT,
              messageCountSupplier,
              this.tags
          );
      }
  
      /**
       * Register a gauge for the in-flight batch count.
       *
       * @param batchCountSupplier The supplier for the in-flight batch count.
       */
      public void registerInFlightBatchCount(Supplier<Integer> batchCountSupplier) {
          metricsGroup.newGauge(
              IN_FLIGHT_BATCH_COUNT,
              batchCountSupplier,
              this.tags
          );
      }
  
      public void recordAcquisitionLockTimeoutPerSec(long count) {
          acquisitionLockTimeoutPerSec.mark(count);
      }
  
      public void recordInFlightBatchMessageCount(long count) {
          inFlightBatchMessageCount.update(count);
      }
  
      public void recordFetchLockTimeMs(long timeMs) {
          fetchLockTimeMs.update(timeMs);
      }
  
      public void recordFetchLockRatio(int value) {
          fetchLockRatio.update(value);
      }
  
      // Visible for testing
      public Meter acquisitionLockTimeoutPerSec() {
          return acquisitionLockTimeoutPerSec;
      }
  
      // Visible for testing
      public Histogram inFlightBatchMessageCount() {
          return inFlightBatchMessageCount;
      }
  
      // Visible for testing
      public Histogram fetchLockTimeMs() {
          return fetchLockTimeMs;
      }
  
      // Visible for testing
      public Histogram fetchLockRatio() {
          return fetchLockRatio;
      }
  
      @Override
      public void close() throws Exception {
          List.of(ACQUISITION_LOCK_TIMEOUT_PER_SEC,
              IN_FLIGHT_MESSAGE_COUNT,
              IN_FLIGHT_BATCH_COUNT,
              IN_FLIGHT_BATCH_MESSAGE_COUNT,
              FETCH_LOCK_TIME_MS,
              FETCH_LOCK_RATIO
          ).forEach(m -> metricsGroup.removeMetric(m, tags));
      }
  }
  