SumLambdaIntegrationTest.java

/**
 * Copyright 2016 Confluent Inc.
 *
 * Licensed 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 io.confluent.examples.streams;

import org.apache.kafka.clients.consumer.ConsumerConfig;
import org.apache.kafka.clients.producer.ProducerConfig;
import org.apache.kafka.common.serialization.IntegerDeserializer;
import org.apache.kafka.common.serialization.IntegerSerializer;
import org.apache.kafka.common.serialization.Serdes;
import org.apache.kafka.streams.KafkaStreams;
import org.apache.kafka.streams.StreamsConfig;
import org.apache.kafka.streams.kstream.KStream;
import org.apache.kafka.streams.kstream.KStreamBuilder;
import org.apache.kafka.streams.kstream.KTable;
import org.junit.BeforeClass;
import org.junit.ClassRule;
import org.junit.Test;

import java.util.Arrays;
import java.util.List;
import java.util.Properties;

import io.confluent.examples.streams.kafka.EmbeddedSingleNodeKafkaCluster;

import static org.assertj.core.api.Assertions.assertThat;

/**
 * End-to-end integration test that shows how to compute the sum of numbers, based on {@link
 * SumLambdaExample}.
 *
 * Note: This example uses lambda expressions and thus works with Java 8+ only.
 */
public class SumLambdaIntegrationTest {

  @ClassRule
  public static final EmbeddedSingleNodeKafkaCluster CLUSTER = new EmbeddedSingleNodeKafkaCluster();

  private static String inputTopic = "inputTopic";
  private static String outputTopic = "outputTopic";

  @BeforeClass
  public static void startKafkaCluster() throws Exception {
    CLUSTER.createTopic(inputTopic);
    CLUSTER.createTopic(outputTopic);
  }

  @Test
  public void shouldSumEvenNumbers() throws Exception {
    List<Integer> inputValues = Arrays.asList(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
    List<Integer> expectedValues = Arrays.asList(2, 6, 12, 20, 30);

    //
    // Step 1: Configure and start the processor topology.
    //
    KStreamBuilder builder = new KStreamBuilder();

    Properties streamsConfiguration = new Properties();
    streamsConfiguration.put(StreamsConfig.APPLICATION_ID_CONFIG, "sum-lambda-integration-test");
    streamsConfiguration.put(StreamsConfig.BOOTSTRAP_SERVERS_CONFIG, CLUSTER.bootstrapServers());
    streamsConfiguration.put(StreamsConfig.ZOOKEEPER_CONNECT_CONFIG, CLUSTER.zookeeperConnect());
    streamsConfiguration.put(StreamsConfig.KEY_SERDE_CLASS_CONFIG, Serdes.Integer().getClass().getName());
    streamsConfiguration.put(StreamsConfig.VALUE_SERDE_CLASS_CONFIG, Serdes.Integer().getClass().getName());
    streamsConfiguration.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "earliest");
    // Explicitly place the state directory under /tmp so that we can remove it via
    // `purgeLocalStreamsState` below.  Once Streams is updated to expose the effective
    // StreamsConfig configuration (so we can retrieve whatever state directory Streams came up
    // with automatically) we don't need to set this anymore and can update `purgeLocalStreamsState`
    // accordingly.
    streamsConfiguration.put(StreamsConfig.STATE_DIR_CONFIG, "/tmp/kafka-streams");

    // Remove any state from previous test runs
    IntegrationTestUtils.purgeLocalStreamsState(streamsConfiguration);

    KStream<Integer, Integer> input = builder.stream(inputTopic);
    KTable<Integer, Integer> sumOfOddNumbers = input
        .filter((k, v) -> v % 2 == 0)
        .selectKey((k, v) -> 1)
        .reduceByKey((v1, v2) -> v1 + v2, "sum");
    sumOfOddNumbers.to(outputTopic);

    KafkaStreams streams = new KafkaStreams(builder, streamsConfiguration);
    streams.start();

    //
    // Step 2: Produce some input data to the input topic.
    //
    Properties producerConfig = new Properties();
    producerConfig.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, CLUSTER.bootstrapServers());
    producerConfig.put(ProducerConfig.ACKS_CONFIG, "all");
    producerConfig.put(ProducerConfig.RETRIES_CONFIG, 0);
    producerConfig.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, IntegerSerializer.class);
    producerConfig.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, IntegerSerializer.class);
    IntegrationTestUtils.produceValuesSynchronously(inputTopic, inputValues, producerConfig);

    //
    // Step 3: Verify the application's output data.
    //
    Properties consumerConfig = new Properties();
    consumerConfig.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, CLUSTER.bootstrapServers());
    consumerConfig.put(ConsumerConfig.GROUP_ID_CONFIG, "sum-lambda-integration-test-standard-consumer");
    consumerConfig.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "earliest");
    consumerConfig.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, IntegerDeserializer.class);
    consumerConfig.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, IntegerDeserializer.class);
    List<String> actualValues = IntegrationTestUtils.waitUntilMinValuesRecordsReceived(consumerConfig,
        outputTopic, expectedValues.size());
    streams.close();
    assertThat(actualValues).isEqualTo(expectedValues);
  }

}