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.integration;
  
  import org.apache.kafka.clients.CommonClientConfigs;
  import org.apache.kafka.common.metrics.KafkaMetric;
  import org.apache.kafka.common.metrics.MetricsReporter;
  import org.apache.kafka.common.serialization.Serdes;
  import org.apache.kafka.streams.KafkaStreams;
  import org.apache.kafka.streams.StreamsBuilder;
  import org.apache.kafka.streams.StreamsConfig;
  import org.apache.kafka.streams.Topology;
  import org.apache.kafka.streams.integration.utils.EmbeddedKafkaCluster;
  import org.apache.kafka.streams.kstream.Consumed;
  import org.apache.kafka.streams.kstream.Produced;
  
  import org.junit.jupiter.api.AfterAll;
  import org.junit.jupiter.api.BeforeAll;
  import org.junit.jupiter.api.BeforeEach;
  import org.junit.jupiter.api.Tag;
  import org.junit.jupiter.api.Test;
  import org.junit.jupiter.api.TestInfo;
  import org.junit.jupiter.api.Timeout;
  
  import java.io.IOException;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  import java.util.Properties;
  
  import static org.apache.kafka.streams.utils.TestUtils.safeUniqueTestName;
  import static org.hamcrest.CoreMatchers.notNullValue;
  import static org.hamcrest.MatcherAssert.assertThat;
  
  @Timeout(600)
  @Tag("integration")
  public class MetricsReporterIntegrationTest {
      private static final int NUM_BROKERS = 1;
  
      public static final EmbeddedKafkaCluster CLUSTER = new EmbeddedKafkaCluster(NUM_BROKERS);
  
      // topic names
      private static final String STREAM_INPUT = "STREAM_INPUT";
      private static final String STREAM_OUTPUT = "STREAM_OUTPUT";
  
      private StreamsBuilder builder;
      private Properties streamsConfiguration;
  
      @BeforeAll
      public static void startCluster() throws IOException {
          CLUSTER.start();
      }
  
      @AfterAll
      public static void closeCluster() {
          CLUSTER.stop();
      }
  
      @BeforeEach
      public void before(final TestInfo testInfo) throws InterruptedException {
          builder = new StreamsBuilder();
  
          final String safeTestName = safeUniqueTestName(testInfo);
          final String appId = "app-" + safeTestName;
  
          streamsConfiguration = new Properties();
          streamsConfiguration.put(StreamsConfig.APPLICATION_ID_CONFIG, appId);
          streamsConfiguration.put(StreamsConfig.BOOTSTRAP_SERVERS_CONFIG, CLUSTER.bootstrapServers());
          streamsConfiguration.put(StreamsConfig.DEFAULT_KEY_SERDE_CLASS_CONFIG, Serdes.Integer().getClass());
          streamsConfiguration.put(StreamsConfig.DEFAULT_VALUE_SERDE_CLASS_CONFIG, Serdes.String().getClass());
          streamsConfiguration.put(CommonClientConfigs.METRIC_REPORTER_CLASSES_CONFIG, MetricReporterImpl.class.getName());
      }
  
      static final Map<String, Object> METRIC_NAME_TO_INITIAL_VALUE = new HashMap<>();
  
      public static class MetricReporterImpl implements MetricsReporter {
  
  
          @Override
          public void configure(final Map<String, ?> configs) {
          }
  
          @Override
          public void init(final List<KafkaMetric> metrics) {
          }
  
          @Override
          public void metricChange(final KafkaMetric metric) {
              // get value of metric, e.g. if you wanted checking the type of the value
              METRIC_NAME_TO_INITIAL_VALUE.put(metric.metricName().name(), metric.metricValue());
          }
  
          @Override
          public void metricRemoval(final KafkaMetric metric) {
          }
  
          @Override
          public void close() {
          }
      }
  
      @Test
      public void shouldBeAbleToProvideInitialMetricValueToMetricsReporter() {
          // no need to create the topics, because we don't start the stream - just need to create the KafkaStreams object
          // to check all initial values from the metrics are not null
          builder.stream(STREAM_INPUT, Consumed.with(Serdes.Integer(), Serdes.String()))
                  .to(STREAM_OUTPUT, Produced.with(Serdes.Integer(), Serdes.String()));
          final Topology topology = builder.build();
          try (KafkaStreams kafkaStreams = new KafkaStreams(topology, streamsConfiguration)) {
              kafkaStreams.metrics().keySet().forEach(metricName -> {
                  final Object initialMetricValue = METRIC_NAME_TO_INITIAL_VALUE.get(metricName.name());
                  assertThat(initialMetricValue, notNullValue());
              });
          }
      }
  
  }
  