Is there an alternative for Axon 2 ClusteringEventBus in Axon4

Imported from Google Groups
1

Greetings,

I’m working on a monolith Enterprise application using SpringFramework 4x & Axon 2.4.6. and the event sourcing infrastructure built on Axon ClusteringEventBus.

The current structure as follows:

multiple clusters for instance those 2 type of clusters:

<axon:cluster id="syncCluster" order="5000">
  <axon:replay-config event-store="eventStore" transaction-manager="transactionManager" commit-threshold="5000"/>
  <axon:selectors>
    <axon:annotation check-superclass="true" type="com.example.ClusterAnnotation"/>
  </axon:selectors>
</axon:cluster>

<axon:cluster id="asyncCluster" order="6000">
  <axon:replay-config event-store="eventStore" transaction-manager="transactionManager" commit-threshold="5000"/>
  <axon:selectors>
    <axon:annotation check-superclass="true" type="com.example.ClusterAnnotation"/>
  </axon:selectors>
  <bean class="org.axonframework.eventhandling.async.AsynchronousCluster">
    <constructor-arg name="identifier" value="myCluster"/>
    <constructor-arg name="executor" ref="asyncExecutor"/>
    <constructor-arg name="transactionManager" ref="clusterTransactionManager"/>
    <constructor-arg name="sequencingPolicy" ref="fullConcurrencyPolicy"/>
    <constructor-arg name="errorHandler" ref="myErrorHandler"/>
  </bean>
</axon:cluster>

and incase of failure, there’s event replay mechanism only for that specific cluster with criteria as follows:

public void replayEventsForAggregate(final String aggregateIdentifier,ReplayingCluster replayCluster){
  final Criteria criteria = getCriteriaThatListAllEventsForAggregate(aggregateIdentifier,replayCluster);
  replayCluster.startReplay(criteria);
}

the goal: is to migrate to Spring framework 5 and Axon 4.

Since cluster event bus is no longer exist in Axon4 what would be the best way to implement such structure in Axon 4 without clustering?

2

Hi Muhammed,

the behavior of the ClusteringEventBus has become the default for EventBus implementations in Axon 3/4. The “Cluster” part is now contained in Event Processors.
So instead of defining “clusters”, configure processing groups with the same non-functionals. To be able to support replays, use a TrackingProcessor.

Hope this helps.
Cheers,