I'm trying to figure out how i can test my Spring Cloud Streams Kafka-Streams application.
The application lookls like this:
Stream 1: Topic1 > Topic2
Stream 2: Topic2 + Topic3 joined > Topic4
Stream 3: Topic4 > Topic5
I tried different approaches like the TestChannelBinder but this approach only works with Simple functions not Streams and Avro.
I decided to use EmbeddedKafka with MockSchemaRegistryClient. I can produce to a topic and also consume from the same topic again (topic1) but i'm not able to consume from (topic2).
In my test application.yaml i put the following configuration (i'm only testing the first stream for now, i want to extend it once this works):
spring.application.name: processingapp
spring.cloud:
function.definition: stream1 # not now ;stream2;stream3
stream:
bindings:
stream1-in-0:
destination: topic1
stream1-out-0:
destination: topic2
kafka:
binder:
min-partition-count: 1
replication-factor: 1
auto-create-topics: true
auto-add-partitions: true
bindings:
default:
consumer:
autoRebalanceEnabled: true
resetOffsets: true
startOffset: earliest
stream1-in-0:
consumer:
keySerde: io.confluent.kafka.streams.serdes.avro.PrimitiveAvroSerde
valueSerde: io.confluent.kafka.streams.serdes.avro.SpecificAvroSerde
stream1-out-0:
producer:
keySerde: io.confluent.kafka.streams.serdes.avro.PrimitiveAvroSerde
valueSerde: io.confluent.kafka.streams.serdes.avro.SpecificAvroSerde
streams:
binder:
configuration:
schema.registry.url: mock://localtest
specivic.avro.reader: true
My test looks like the following:
@RunWith(SpringRunner.class)
@SpringBootTest
public class Test {
private static final String INPUT_TOPIC = "topic1";
private static final String OUTPUT_TOPIC = "topic2";
@ClassRule
public static EmbeddedKafkaRule embeddedKafka = new EmbeddedKafkaRule(1, true, 1, INPUT_TOPIC, OUTPUT_TOPIC);
@BeforeClass
public static void setup() {
System.setProperty("spring.cloud.stream.kafka.binder.brokers", embeddedKafka.getEmbeddedKafka().getBrokersAsString());
}
@org.junit.Test
public void testSendReceive() throws IOException {
Map<String, Object> senderProps = KafkaTestUtils.producerProps(embeddedKafka.getEmbeddedKafka());
senderProps.put("key.serializer", LongSerializer.class);
senderProps.put("value.serializer", SpecificAvroSerializer.class);
senderProps.put("schema.registry.url", "mock://localtest");
AvroFileParser fileParser = new AvroFileParser();
DefaultKafkaProducerFactory<Long, Test1> pf = new DefaultKafkaProducerFactory<>(senderProps);
KafkaTemplate<Long, Test1> template = new KafkaTemplate<>(pf, true);
Test1 test1 = fileParser.parseTest1("src/test/resources/mocks/test1.json");
template.send(INPUT_TOPIC, 123456L, test1);
System.out.println("produced");
Map<String, Object> consumer1Props = KafkaTestUtils.consumerProps("testConsumer1", "false", embeddedKafka.getEmbeddedKafka());
consumer1Props.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "earliest");
consumer1Props.put("key.deserializer", LongDeserializer.class);
consumer1Props.put("value.deserializer", SpecificAvroDeserializer.class);
consumer1Props.put("schema.registry.url", "mock://localtest");
DefaultKafkaConsumerFactory<Long, Test1> cf = new DefaultKafkaConsumerFactory<>(consumer1Props);
Consumer<Long, Test1> consumer1 = cf.createConsumer();
consumer1.subscribe(Collections.singleton(INPUT_TOPIC));
ConsumerRecords<Long, Test1> records = consumer1.poll(Duration.ofSeconds(10));
consumer1.commitSync();
System.out.println("records count?");
System.out.println("" + records.count());
Test1 fetchedTest1;
fetchedTest1 = records.iterator().next().value();
assertThat(records.count()).isEqualTo(1);
System.out.println("found record");
System.out.println(fetchedTest1.toString());
Map<String, Object> consumer2Props = KafkaTestUtils.consumerProps("testConsumer2", "false", embeddedKafka.getEmbeddedKafka());
consumer2Props.put("key.deserializer", StringDeserializer.class);
consumer2Props.put("value.deserializer", TestAvroDeserializer.class);
consumer2Props.put("schema.registry.url", "mock://localtest");
DefaultKafkaConsumerFactory<String, Test2> consumer2Factory = new DefaultKafkaConsumerFactory<>(consumer2Props);
Consumer<String, Test2> consumer2 = consumer2Factory.createConsumer();
consumer2.subscribe(Collections.singleton(OUTPUT_TOPIC));
ConsumerRecords<String, Test2> records2 = consumer2.poll(Duration.ofSeconds(30));
consumer2.commitSync();
if (records2.iterator().hasNext()) {
System.out.println("has next");
} else {
System.out.println("has no next");
}
}
}
I receive the following exception when trying to consume and deserialize from topic2:
Caused by: org.apache.kafka.common.errors.SerializationException: Error retrieving Avro unknown schema for id 0
Caused by: java.io.IOException: Cannot get schema from schema registry!
at io.confluent.kafka.schemaregistry.client.MockSchemaRegistryClient.getSchemaBySubjectAndIdFromRegistry(MockSchemaRegistryClient.java:193) ~[kafka-schema-registry-client-6.2.0.jar:na]
at io.confluent.kafka.schemaregistry.client.MockSchemaRegistryClient.getSchemaBySubjectAndId(MockSchemaRegistryClient.java:249) ~[kafka-schema-registry-client-6.2.0.jar:na]
at io.confluent.kafka.schemaregistry.client.MockSchemaRegistryClient.getSchemaById(MockSchemaRegistryClient.java:232) ~[kafka-schema-registry-client-6.2.0.jar:na]
at io.confluent.kafka.serializers.AbstractKafkaAvroDeserializer$DeserializationContext.schemaFromRegistry(AbstractKafkaAvroDeserializer.java:307) ~[kafka-avro-serializer-6.2.0.jar:na]
at io.confluent.kafka.serializers.AbstractKafkaAvroDeserializer.deserialize(AbstractKafkaAvroDeserializer.java:107) ~[kafka-avro-serializer-6.2.0.jar:na]
at io.confluent.kafka.serializers.AbstractKafkaAvroDeserializer.deserialize(AbstractKafkaAvroDeserializer.java:86) ~[kafka-avro-serializer-6.2.0.jar:na]
at io.confluent.kafka.serializers.KafkaAvroDeserializer.deserialize(KafkaAvroDeserializer.java:55) ~[kafka-avro-serializer-6.2.0.jar:na]
at org.apache.kafka.common.serialization.Deserializer.deserialize(Deserializer.java:60) ~[kafka-clients-2.7.1.jar:na]
at org.apache.kafka.streams.processor.internals.SourceNode.deserializeKey(SourceNode.java:54) ~[kafka-streams-2.7.1.jar:na]
at org.apache.kafka.streams.processor.internals.RecordDeserializer.deserialize(RecordDeserializer.java:65) ~[kafka-streams-2.7.1.jar:na]
at org.apache.kafka.streams.processor.internals.RecordQueue.updateHead(RecordQueue.java:176) ~[kafka-streams-2.7.1.jar:na]
at org.apache.kafka.streams.processor.internals.RecordQueue.addRawRecords(RecordQueue.java:112) ~[kafka-streams-2.7.1.jar:na]
at org.apache.kafka.streams.processor.internals.PartitionGroup.addRawRecords(PartitionGroup.java:185) ~[kafka-streams-2.7.1.jar:na]
at org.apache.kafka.streams.processor.internals.StreamTask.addRecords(StreamTask.java:895) ~[kafka-streams-2.7.1.jar:na]
at org.apache.kafka.streams.processor.internals.TaskManager.addRecordsToTasks(TaskManager.java:1008) ~[kafka-streams-2.7.1.jar:na]
at org.apache.kafka.streams.processor.internals.StreamThread.pollPhase(StreamThread.java:812) ~[kafka-streams-2.7.1.jar:na]
at org.apache.kafka.streams.processor.internals.StreamThread.runOnce(StreamThread.java:625) ~[kafka-streams-2.7.1.jar:na]
at org.apache.kafka.streams.processor.internals.StreamThread.runLoop(StreamThread.java:564) ~[kafka-streams-2.7.1.jar:na]
at org.apache.kafka.streams.processor.internals.StreamThread.run(StreamThread.java:523) ~[kafka-streams-2.7.1.jar:na]
There won't be a message consumed.
So i tried to overwrite the SpecificAvroSerde and register the schemas directly and use this deserializer.
public class TestAvroDeserializer<T extends org.apache.avro.specific.SpecificRecord>
extends SpecificAvroDeserializer<T> implements Deserializer<T> {
private final KafkaAvroDeserializer inner;
public TestAvroDeserializer() throws IOException, RestClientException {
MockSchemaRegistryClient mockedClient = new MockSchemaRegistryClient();
Schema.Parser parser = new Schema.Parser();
Schema test2Schema = parser.parse(new File("./src/main/resources/avro/test2.avsc"));
mockedClient.register("test2-value", test2Schema , 1, 0);
inner = new KafkaAvroDeserializer(mockedClient);
}
/**
* For testing purposes only.
*/
TestAvroDeserializer(final SchemaRegistryClient client) throws IOException, RestClientException {
MockSchemaRegistryClient mockedClient = new MockSchemaRegistryClient();
Schema.Parser parser = new Schema.Parser();
Schema test2Schema = parser.parse(new File("./src/main/resources/avro/test2.avsc"));
mockedClient.register("test2-value", test2Schema , 1, 0);
inner = new KafkaAvroDeserializer(mockedClient);
}
}
With this deserializer it won't work too. Does anyone have experience on how to do this tests with EmbeddedKafka and MockSchemaRegistry? Or is there another approach i should use?
I'm very glad if someone can help. Thank you in advance.
I found an appropriate way of integration testing my topology.
I use the TopologyTestDriver from the kafka-streams-test-utils package.
Include this dependency to Maven:
<dependency>
<groupId>org.apache.kafka</groupId>
<artifactId>kafka-streams-test-utils</artifactId>
<scope>test</scope>
</dependency>
For the application described in the question setting up the TopologyTestDriver would look like the following. This code is just sequentially to show how it works.
@Test
void test() {
keySerde.configure(Map.of(KafkaAvroSerializerConfig.SCHEMA_REGISTRY_URL_CONFIG, "mock://schemas"), true);
valueSerdeTopic1.configure(Map.of(KafkaAvroSerializerConfig.SCHEMA_REGISTRY_URL_CONFIG, "mock://schemas"), false);
valueSerdeTopic2.configure(Map.of(KafkaAvroSerializerConfig.SCHEMA_REGISTRY_URL_CONFIG, "mock://schemas"), false);
final StreamsBuilder builder = new StreamsBuilder();
Configuration config = new Configuration(); // class where you declare your spring cloud stream functions
KStream<String, Topic1> input = builder.stream("topic1", Consumed.with(keySerde, valueSerdeTopic1));
KStream<String, Topic2> output = config.stream1().apply(input);
output.to("topic2");
Topology topology = builder.build();
Properties streamsConfig = new Properties();
streamsConfig.putAll(Map.of(
org.apache.kafka.streams.StreamsConfig.APPLICATION_ID_CONFIG, "toplogy-test-driver",
org.apache.kafka.streams.StreamsConfig.BOOTSTRAP_SERVERS_CONFIG, "ignored",
KafkaAvroSerializerConfig.SCHEMA_REGISTRY_URL_CONFIG, "mock://schemas",
org.apache.kafka.streams.StreamsConfig.DEFAULT_KEY_SERDE_CLASS_CONFIG, PrimitiveAvroSerde.class.getName(),
org.apache.kafka.streams.StreamsConfig.DEFAULT_VALUE_SERDE_CLASS_CONFIG, SpecificAvroSerde.class.getName()
));
TopologyTestDriver testDriver = new TopologyTestDriver(topology, streamsConfig);
TestInputTopic<String, Topic1> inputTopic = testDriver.createInputTopic("topic1", keySerde.serializer(), valueSerdeTopic1.serializer());
TestOutputTopic<String, Topic2> outputTopic = testDriver.createOutputTopic("topic2", keySerde.deserializer(), valueSerdeTopic2.deserializer());
inputTopic.pipeInput("key", topic1AvroModel); // Write to the input topic which applies the topology processor of your spring-cloud-stream app
KeyValue<String, Topic2> outputRecord = outputTopic.readKeyValue(); // Read from the output topic
}
If you write more tests i recommend to abstract the setup code to not repeat yourself for each test. I highly suggest this example from the spring-cloud-streams-samples repository, it leaded me to the solution to use TopologyTestDriver.