This sample demonstrates a simple Kafka Streams topology tested with TopologyTestDriver.
The application contains a simple Kafka Streams topology that counts the keys seen so far in a stateful manner.
The corresponding TopologyTestDriver based JUnit test verifies the behavior of the business logic in the Kafka Streams topology.
Console output describe the topology as shown below:
-
_ _ _ _ /\\ / '_ _ ()_ _ \ \ \ \ ( ( )_ | '_ | '| | ' \/ ` | \ \ \ \ \\/ __)| |)| | | | | || (| | ) ) ) ) ' |_| .|| ||| |_, | / / / / =========||==============|__/=///_/
- :: Spring Boot
-
(v2.5.2)
2021-06-30 17:38:33.637 INFO 92063 --- [ main] com.example.ApplicationTests : Starting ApplicationTests using Java 11.0.10 on C02FL1KSMD6T with PID 92063 (started by igomez in /Users/igomez/Projects/spring-kafka/samples/sample-05) 2021-06-30 17:38:33.638 INFO 92063 --- [ main] com.example.ApplicationTests : The following profiles are active: test 2021-06-30 17:38:35.027 INFO 92063 --- [ main] com.example.ApplicationTests : Started ApplicationTests in 1.73 seconds (JVM running for 2.833) 2021-06-30 17:38:35.695 INFO 92063 --- [ main] com.example.ApplicationTests : Topologies: Sub-topology: 0 Source: KSTREAM-SOURCE-0000000000 (topics: [input]) -→ KSTREAM-AGGREGATE-0000000002 Processor: KSTREAM-AGGREGATE-0000000002 (stores: [KSTREAM-AGGREGATE-STATE-STORE-0000000001]) -→ KTABLE-SUPPRESS-0000000003 ←- KSTREAM-SOURCE-0000000000 Processor: KTABLE-SUPPRESS-0000000003 (stores: [KTABLE-SUPPRESS-STATE-STORE-0000000004]) -→ KTABLE-TOSTREAM-0000000005 ←- KSTREAM-AGGREGATE-0000000002 Processor: KTABLE-TOSTREAM-0000000005 (stores: []) -→ KSTREAM-SINK-0000000006 ←- KTABLE-SUPPRESS-0000000003 Sink: KSTREAM-SINK-0000000006 (topic: output) ←- KTABLE-TOSTREAM-0000000005