[GitHub] [kafka] jnh5y commented on a diff in pull request #12161: KAFKA-13873 Add ability to Pause / Resume KafkaStreams Topologies

[GitBox <gi...@apache.org>]

jnh5y commented on code in PR #12161:
URL: https://github.com/apache/kafka/pull/12161#discussion_r887056404


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streams/src/test/java/org/apache/kafka/streams/integration/PauseResumeIntegrationTest.java:
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@@ -0,0 +1,445 @@
+/*
+ * 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 static java.util.Arrays.asList;
+import static java.util.Collections.singletonList;
+import static org.apache.kafka.streams.KeyValue.pair;
+import static org.apache.kafka.streams.integration.utils.IntegrationTestUtils.safeUniqueTestName;
+import static org.apache.kafka.streams.integration.utils.IntegrationTestUtils.waitForApplicationState;
+import static org.apache.kafka.streams.integration.utils.IntegrationTestUtils.waitUntilMinKeyValueRecordsReceived;
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import java.time.Duration;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+import java.util.Properties;
+import org.apache.kafka.clients.consumer.ConsumerConfig;
+import org.apache.kafka.common.serialization.LongDeserializer;
+import org.apache.kafka.common.serialization.LongSerializer;
+import org.apache.kafka.common.serialization.Serdes;
+import org.apache.kafka.common.serialization.StringDeserializer;
+import org.apache.kafka.common.serialization.StringSerializer;
+import org.apache.kafka.common.utils.Bytes;
+import org.apache.kafka.streams.KafkaStreams;
+import org.apache.kafka.streams.KafkaStreams.State;
+import org.apache.kafka.streams.KeyValue;
+import org.apache.kafka.streams.LagInfo;
+import org.apache.kafka.streams.StreamsBuilder;
+import org.apache.kafka.streams.StreamsConfig;
+import org.apache.kafka.streams.integration.utils.EmbeddedKafkaCluster;
+import org.apache.kafka.streams.integration.utils.IntegrationTestUtils;
+import org.apache.kafka.streams.kstream.Materialized;
+import org.apache.kafka.streams.processor.internals.namedtopology.KafkaStreamsNamedTopologyWrapper;
+import org.apache.kafka.streams.processor.internals.namedtopology.NamedTopologyBuilder;
+import org.apache.kafka.streams.state.KeyValueStore;
+import org.apache.kafka.streams.state.Stores;
+import org.apache.kafka.test.IntegrationTest;
+import org.apache.kafka.test.TestUtils;
+import org.hamcrest.CoreMatchers;
+import org.junit.After;
+import org.junit.AfterClass;
+import org.junit.Before;
+import org.junit.BeforeClass;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.experimental.categories.Category;
+import org.junit.rules.TestName;
+
+@Category({IntegrationTest.class})
+public class PauseResumeIntegrationTest {
+    private static final Duration STARTUP_TIMEOUT = Duration.ofSeconds(45);
+    private static final int NUM_BROKERS = 1;
+
+    public static final EmbeddedKafkaCluster CLUSTER = new EmbeddedKafkaCluster(NUM_BROKERS);
+    private static Properties producerConfig;
+    private static Properties consumerConfig;
+
+    private static final Materialized<Object, Long, KeyValueStore<Bytes, byte[]>> IN_MEMORY_STORE =
+        Materialized.as(Stores.inMemoryKeyValueStore("store"));
+
+    private static final String INPUT_STREAM_1 = "input-stream-1";
+    private static final String INPUT_STREAM_2 = "input-stream-2";
+
+    private static final String OUTPUT_STREAM_1 = "output-stream-1";
+    private static final String OUTPUT_STREAM_2 = "output-stream-2";
+    
+    private static final String TOPOLOGY1 = "topology1";
+    private static final String TOPOLOGY2 = "topology2";
+
+    private static final List<KeyValue<String, Long>> STANDARD_INPUT_DATA =
+        asList(pair("A", 100L), pair("B", 200L), pair("A", 300L), pair("C", 400L), pair("C", -50L));
+    private static final List<KeyValue<String, Long>> COUNT_OUTPUT_DATA =
+        asList(pair("B", 1L), pair("A", 2L), pair("C", 2L));
+    private static final List<KeyValue<String, Long>> COUNT_OUTPUT_DATA2 =
+        asList(pair("B", 2L), pair("A", 4L), pair("C", 4L));
+
+    @BeforeClass
+    public static void startCluster() throws Exception {
+        CLUSTER.start();
+
+        producerConfig = TestUtils.producerConfig(CLUSTER.bootstrapServers(),
+            StringSerializer.class, LongSerializer.class);
+        consumerConfig = TestUtils.consumerConfig(CLUSTER.bootstrapServers(),
+            StringDeserializer.class, LongDeserializer.class);
+    }
+
+    @AfterClass
+    public static void closeCluster() {
+        CLUSTER.stop();
+    }
+
+    @Rule
+    public final TestName testName = new TestName();
+    private String appId;
+    private KafkaStreams kafkaStreams;
+    private KafkaStreamsNamedTopologyWrapper streamsNamedTopologyWrapper;
+
+    @Before
+    public void createTopics() throws InterruptedException {
+        appId = safeUniqueTestName(PauseResumeIntegrationTest.class, testName);
+
+        CLUSTER.createTopic(INPUT_STREAM_1, 2, 1);
+        CLUSTER.createTopic(INPUT_STREAM_2, 2, 1);
+        CLUSTER.createTopic(OUTPUT_STREAM_1, 2, 1);
+        CLUSTER.createTopic(OUTPUT_STREAM_2, 2, 1);
+    }
+
+    private Properties props() {
+        final Properties properties = new Properties();
+        properties.put(StreamsConfig.APPLICATION_ID_CONFIG, appId);
+        properties.put(StreamsConfig.BOOTSTRAP_SERVERS_CONFIG, CLUSTER.bootstrapServers());
+        properties.put(StreamsConfig.STATE_DIR_CONFIG,
+            TestUtils.tempDirectory(appId).getPath());
+        properties.put(StreamsConfig.DEFAULT_KEY_SERDE_CLASS_CONFIG, Serdes.String().getClass());
+        properties.put(StreamsConfig.DEFAULT_VALUE_SERDE_CLASS_CONFIG, Serdes.Long().getClass());
+        properties.put(StreamsConfig.COMMIT_INTERVAL_MS_CONFIG, 1000L);
+        properties.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "earliest");
+        properties.put(StreamsConfig.TOPOLOGY_OPTIMIZATION_CONFIG, StreamsConfig.OPTIMIZE);
+        return properties;
+    }
+
+    @After
+    public void shutdown() throws InterruptedException {
+        if (kafkaStreams != null) {
+            kafkaStreams.close(Duration.ofSeconds(30));
+        }
+        if (streamsNamedTopologyWrapper != null) {
+            streamsNamedTopologyWrapper.close(Duration.ofSeconds(30));
+        }
+        CLUSTER.deleteTopicsAndWait(INPUT_STREAM_1);
+        CLUSTER.deleteTopicsAndWait(INPUT_STREAM_2);
+        CLUSTER.deleteTopicsAndWait(OUTPUT_STREAM_1);
+        CLUSTER.deleteTopicsAndWait(OUTPUT_STREAM_2);
+    }
+
+    private static void produceToInputTopics(final String topic,
+        final Collection<KeyValue<String, Long>> records) {
+        IntegrationTestUtils.produceKeyValuesSynchronously(
+            topic,
+            records,
+            producerConfig,
+            CLUSTER.time
+        );
+    }
+
+
+    @Test
+    public void shouldPauseAndResumeKafkaStreams() throws Exception {
+        // Create KafkaStreams instance
+        final StreamsBuilder builder = new StreamsBuilder();
+        builder.stream(INPUT_STREAM_1).groupByKey().count().toStream().to(OUTPUT_STREAM_1);
+
+        kafkaStreams = new KafkaStreams(builder.build(props()), props());
+        kafkaStreams.start();
+        waitForApplicationState(singletonList(kafkaStreams), State.RUNNING, STARTUP_TIMEOUT);
+
+        // Write data
+        produceToInputTopics(INPUT_STREAM_1, STANDARD_INPUT_DATA);
+
+        // Verify output
+        assertThat(waitUntilMinKeyValueRecordsReceived(consumerConfig, OUTPUT_STREAM_1, 3),
+            CoreMatchers.equalTo(COUNT_OUTPUT_DATA));
+
+        // Pause KafkaStreams/topology
+        kafkaStreams.pause();
+        assertTrue(kafkaStreams.isPaused());
+
+        // Write more data
+        produceToInputTopics(INPUT_STREAM_1, STANDARD_INPUT_DATA);
+
+        // Verify that consumers read new data -- AKA, there is no lag.
+        final Map<String, Map<Integer, LagInfo>> lagMap = kafkaStreams.allLocalStorePartitionLags();
+        assertNoLag(lagMap);

Review Comment:
   Ayup, that's what I understand and it is showing that the active task consumers are still reading (up until their buffers are full).



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