From: Kai Moritz <kai@juplo.de>
Date: Sun, 10 Apr 2022 20:50:44 +0000 (+0200)
Subject: Tests: Der EndlessConsumer wird jetzt doch asynchron ausgeführt
X-Git-Tag: wip-DEPRECATED~11^2^2~14
X-Git-Url: http://juplo.de/gitweb/?a=commitdiff_plain;h=0e0f30edc9bdcd230db1e7f4cbe414f85d5d288a;p=demos%2Fkafka%2Ftraining

Tests: Der EndlessConsumer wird jetzt doch asynchron ausgeführt

* Der Test-Code wird verständlicher, wenn der Consumer asynchron läuft
* Für die Überprüfung der Erwartungen wird dann awaitility benötigt
** Da der Consumer in einem separaten Thread läuft, muss auf diesen
   gezielt gewartet werden
** Dafür wird es deutlicher/verständlicher, auf welche der auch aus dem
   regulären Betrieb des EndlessConsumer bekannten Zustandsänderungen
   der Test wartet
* Da die Offsets für die Controlle (ggf.) abgefragt werden, während der
  EndlessConsumer noch läuft, wird ein separater KafkaConsumer benötigt,
  um die Offsets abzurufen.
  BEACHTE: Um die Änderungen in dem Offsets-Topic zu greifen zu bekommen,
  muss dieser KafkaConsumer für jede Abfrage ein `assign()` durchführen,
  damit er gezwungen ist, die Offsets neu vom Broker zu erfragen.
---

diff --git a/pom.xml b/pom.xml
index c01ed2c..f218085 100644
--- a/pom.xml
+++ b/pom.xml
@@ -52,6 +52,11 @@
       <artifactId>spring-kafka-test</artifactId>
       <scope>test</scope>
     </dependency>
+    <dependency>
+      <groupId>org.awaitility</groupId>
+      <artifactId>awaitility</artifactId>
+      <scope>test</scope>
+    </dependency>
   </dependencies>
 
   <build>
diff --git a/src/test/java/de/juplo/kafka/ApplicationTests.java b/src/test/java/de/juplo/kafka/ApplicationTests.java
index 6aaff52..bf38b05 100644
--- a/src/test/java/de/juplo/kafka/ApplicationTests.java
+++ b/src/test/java/de/juplo/kafka/ApplicationTests.java
@@ -6,15 +6,12 @@ import org.apache.kafka.clients.consumer.KafkaConsumer;
 import org.apache.kafka.clients.producer.KafkaProducer;
 import org.apache.kafka.clients.producer.ProducerRecord;
 import org.apache.kafka.common.TopicPartition;
-import org.apache.kafka.common.errors.WakeupException;
+import org.apache.kafka.common.serialization.BytesDeserializer;
 import org.apache.kafka.common.serialization.BytesSerializer;
 import org.apache.kafka.common.serialization.LongSerializer;
 import org.apache.kafka.common.serialization.StringSerializer;
 import org.apache.kafka.common.utils.Bytes;
-import org.junit.jupiter.api.MethodOrderer;
-import org.junit.jupiter.api.Order;
-import org.junit.jupiter.api.Test;
-import org.junit.jupiter.api.TestMethodOrder;
+import org.junit.jupiter.api.*;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.test.context.ConfigDataApplicationContextInitializer;
 import org.springframework.boot.test.context.TestConfiguration;
@@ -24,7 +21,9 @@ import org.springframework.kafka.test.context.EmbeddedKafka;
 import org.springframework.test.context.TestPropertySource;
 import org.springframework.test.context.junit.jupiter.SpringJUnitConfig;
 
+import java.time.Duration;
 import java.util.*;
+import java.util.concurrent.ExecutionException;
 import java.util.concurrent.ExecutorService;
 import java.util.function.BiConsumer;
 import java.util.function.Consumer;
@@ -35,6 +34,7 @@ import java.util.stream.IntStream;
 import static de.juplo.kafka.ApplicationTests.PARTITIONS;
 import static de.juplo.kafka.ApplicationTests.TOPIC;
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.awaitility.Awaitility.*;
 
 
 @SpringJUnitConfig(initializers = ConfigDataApplicationContextInitializer.class)
@@ -59,27 +59,32 @@ class ApplicationTests
 	@Autowired
 	KafkaConsumer<String, Long> kafkaConsumer;
 	@Autowired
+	KafkaConsumer<Bytes, Bytes> offsetConsumer;
+	@Autowired
 	ApplicationProperties properties;
 	@Autowired
 	ExecutorService executor;
 
+	Consumer<ConsumerRecord<String, Long>> testHandler;
+	EndlessConsumer<String, Long> endlessConsumer;
 	Map<TopicPartition, Long> oldOffsets;
 	Map<TopicPartition, Long> newOffsets;
 
 
 	@Test
 	@Order(1) // << The poistion pill is not skipped. Hence, this test must run first
-	void commitsCurrentOffsetsOnSuccess()
+	void commitsCurrentOffsetsOnSuccess() throws ExecutionException, InterruptedException
 	{
 		send100Messages(i ->  new Bytes(longSerializer.serialize(TOPIC, i)));
 
 		Set<ConsumerRecord<String, Long>> received = new HashSet<>();
-		runEndlessConsumer(record ->
-		{
-			received.add(record);
-			if (received.size() == 100)
-				throw new WakeupException();
-		});
+		testHandler = record -> received.add(record);
+
+		await("100 records received")
+				.atMost(Duration.ofSeconds(30))
+				.until(() -> received.size() >= 100);
+
+		endlessConsumer.stop();
 
 		checkSeenOffsetsForProgress();
 		compareToCommitedOffsets(newOffsets);
@@ -94,7 +99,9 @@ class ApplicationTests
 						? new Bytes(stringSerializer.serialize(TOPIC, "BOOM!"))
 						: new Bytes(longSerializer.serialize(TOPIC, counter)));
 
-		runEndlessConsumer((record) -> {});
+		await("Consumer failed")
+				.atMost(Duration.ofSeconds(30))
+				.until(() -> !endlessConsumer.running());
 
 		checkSeenOffsetsForProgress();
 		compareToCommitedOffsets(oldOffsets);
@@ -142,8 +149,11 @@ class ApplicationTests
 		}
 	}
 
-	EndlessConsumer<String, Long> runEndlessConsumer(Consumer<ConsumerRecord<String, Long>> consumer)
+	@BeforeEach
+	public void init()
 	{
+		testHandler = record -> {} ;
+
 		oldOffsets = new HashMap<>();
 		newOffsets = new HashMap<>();
 
@@ -153,23 +163,24 @@ class ApplicationTests
 			newOffsets.put(tp, offset - 1);
 		});
 
-		Consumer<ConsumerRecord<String, Long>> captureOffset =
+		Consumer<ConsumerRecord<String, Long>> captureOffsetAndExecuteTestHandler =
 				record ->
-						newOffsets.put(
-								new TopicPartition(record.topic(), record.partition()),
-								record.offset());
+				{
+					newOffsets.put(
+							new TopicPartition(record.topic(), record.partition()),
+							record.offset());
+					testHandler.accept(record);
+				};
 
-		EndlessConsumer<String, Long> endlessConsumer =
+		endlessConsumer =
 				new EndlessConsumer<>(
 						executor,
 						properties.getClientId(),
 						properties.getTopic(),
 						kafkaConsumer,
-						captureOffset.andThen(consumer));
-
-		endlessConsumer.run();
+						captureOffsetAndExecuteTestHandler);
 
-		return endlessConsumer;
+		endlessConsumer.start();
 	}
 
 	List<TopicPartition> partitions()
@@ -183,9 +194,9 @@ class ApplicationTests
 
 	void doForCurrentOffsets(BiConsumer<TopicPartition, Long> consumer)
 	{
-		kafkaConsumer.assign(partitions());
-		partitions().forEach(tp -> consumer.accept(tp, kafkaConsumer.position(tp)));
-		kafkaConsumer.unsubscribe();
+		offsetConsumer.assign(partitions());
+		partitions().forEach(tp -> consumer.accept(tp, offsetConsumer.position(tp)));
+		offsetConsumer.unsubscribe();
 	}
 
 	void checkSeenOffsetsForProgress()
@@ -216,6 +227,19 @@ class ApplicationTests
 	}
 
 
+	@AfterEach
+	public void deinit()
+	{
+		try
+		{
+			endlessConsumer.stop();
+		}
+		catch (Exception e)
+		{
+			log.info("Exception while stopping the consumer: {}", e.toString());
+		}
+	}
+
 	@TestConfiguration
 	@Import(ApplicationConfiguration.class)
 	public static class Configuration
@@ -231,5 +255,18 @@ class ApplicationTests
 
 			return new KafkaProducer<>(props);
 		}
+
+		@Bean
+		KafkaConsumer<Bytes, Bytes> offsetConsumer(ApplicationProperties properties)
+		{
+			Properties props = new Properties();
+			props.put("bootstrap.servers", properties.getBootstrapServer());
+			props.put("client.id", "OFFSET-CONSUMER");
+			props.put("group.id", properties.getGroupId());
+			props.put("key.deserializer", BytesDeserializer.class.getName());
+			props.put("value.deserializer", BytesDeserializer.class.getName());
+
+			return new KafkaConsumer<>(props);
+		}
 	}
 }