a2f642ebe4
Resolves https://github.com/spring-cloud/spring-cloud-stream-samples/issues/65 Polishing - PR Comments - add docker-compose - change runner to process multiple messages
58 lines
2.1 KiB
Markdown
58 lines
2.1 KiB
Markdown
Spring Cloud Stream Polled Consumer with Embedded Kafka Broker Sample
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=====================================================================
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In this *Spring Cloud Stream* sample, an embedded kafka broker is used for testing a polled consumer.
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## Requirements
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To run this sample, you will need to have installed:
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* Java 8 or Above
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## Code Tour
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This sample is a Spring Boot application that uses Spring Cloud Stream to receive a `String` message and forward an upper case version of that String; it uses the Kafka binder.
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It uses a Polled Consumer (rather than a message-driven `@StreamListener`).
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* PolledConsumerApplication - the Spring Boot Main Application
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* PolledConsumerApplicationTests - the test case
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The `spring-kafka-test` dependency added to the `pom.xml` puts the `KafkaEmbedded` JUnit `@Rule` on the class path.
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Refer to the [Spring for Apache Kafka Reference Manual](http://docs.spring.io/spring-kafka/reference/htmlsingle/#testing) for more information about this.
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Notice how the `@BeforeClass` method sets up the Boot and binder properties to locate the servers.
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See the test method for the details on interacting with Embedded Kafka.
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The test method starts by sending a message to the input destination.
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It then creates a consumer to consume from the output destination; gets the output message and asserts that it's an upper case version of the sent message.
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## Building with Maven
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Build the sample and run the test by executing:
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`./mvnw clean package`
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or run the test in your favorite IDE.
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=== Running the app:
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Go to the root of the repository and do:
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`docker-compose up -d`
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`./mvnw clean package`
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`java -jar target/polled-consumer-0.0.1-SNAPSHOT.jar`
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Then send/receive messages to/from the topics.
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`$ docker exec -it kafka-polledconsumer /opt/kafka/bin/kafka-console-producer.sh --broker-list 127.0.0.1:9092 --topic polledConsumerIn`
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On another terminal:
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and
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`$ docker exec -it kafka-polledconsumer /opt/kafka/bin/kafka-console-consumer.sh --bootstrap-server 127.0.0.1:9092 --topic polledConsumerOut --from-beginning`
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Once you are done testing, stop the Kafka cluster: `docker-compose down`
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