Chapter 23. Configuring a service and the KIE Server to emit Kafka messages when a transaction is committed

You can configure the KIE Server to emit Kafka messages about every event when a process, case, or task is completed. The KIE Server sends the messages when it commits transactions.

You can use this functionality with any business process or case. You do not need to change anything in the process design.

This configuration is also available if you run your process service using SpringBoot.

By default, the KIE Server publishes the messages in the following topics:

  • jbpm-processes-events for messages about completed processes
  • jbpm-tasks-events for messages about completed tasks
  • jbpm-cases-events for messages about completed cases

You can configure the topic names.

The published messages comply with the CloudEvents specification version 1.0. Each message contains the following fields:

  • id: The unique identifier of the event
  • type: The type of the event (process, task, or case)
  • source: The event source as a URI
  • time: The timestamp of the event, by default in the RFC3339 format
  • data: Information about the process, case, or task, presented in a JSON format

Procedure

  1. To enable emitting Kafka messages, complete one of the following steps:

    1. If you deployed the KIE Server on Red Hat JBoss EAP or another application server:

      1. Download the rhpam-7.11.0-maven-repository.zip product deliverable file from the Software Downloads page of the Red Hat Customer Portal.
      2. Extract the contents of the file.
      3. Copy the maven-repository/org/jbpm/jbpm-event-emitters-kafka/7.52.0.Final-redhat-00007/jbpm-event-emitters-kafka-7.52.0.Final-redhat-00007.jar file into the deployments/kie-server.war/WEB-INF/lib subdirectory of the application server.
    2. If you deployed the application using SpringBoot, add the following lines to the <dependencies> list in the pom.xml file of your service:

      <dependency>
        <groupId>org.jbpm</groupId>
        <artifactId>jbpm-event-emitters-kafka</artifactId>
        <version>${version.org.kie}</version>
      </dependency>
  2. Configure any of the following system properties for the KIE Server as necessary:

    • org.kie.jbpm.event.emitters.kafka.bootstrap.servers: The host and port of the Kafka broker. The default value is localhost:9092. You can use a comma-separated list of multiple host:port pairs.
    • org.kie.jbpm.event.emitters.kafka.date_format: The timestamp format for the time field of the messages. The default value is yyyy-MM-dd’T’HH:mm:ss.SSSZ .
    • org.kie.jbpm.event.emitters.kafka.topic.processes: The topic name for process event messages. The default value is jbpm-processes-events.
    • org.kie.jbpm.event.emitters.kafka.topic.cases: The topic name for process event messages. The default value is jbpm-cases-events.
    • org.kie.jbpm.event.emitters.kafka.topic.tasks: The topic name for process event messages. The default value is jbpm-processes-tasks.
    • org.kie.jbpm.event.emitters.kafka.client.id: An identifier string to pass to the server when making requests. The server uses this string for logging.