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Custom message logs

Fluxzero supports custom message logs in addition to built-in ones like commands, events, and queries.

Most applications won’t need them — but they’re powerful for advanced use cases like:

  • Tracking external systems or integrations without cluttering your main event log
  • Publishing low-frequency control signals or batched updates for downstream consumers
  • Isolating workflows with different delivery or retention guarantees

Fluxzero lets you define and handle custom messages by assigning them to user-defined topics. Each topic has its own durable log and behaves just like a native command/event/query log.

Handling messages from a custom log

Section titled “Handling messages from a custom log”

To receive messages from a custom log, annotate your handler with @HandleCustom and specify the topic name.

@HandleCustom("metering-points")
void on(MeteringPoint event) {
    log.info("Metering point: {}", event);
}

Custom handlers support everything native handlers do:

  • Stateless or @Stateful
  • Optional results if it’s a request
  • Use of custom consumers
  • Segment routing and metadata access
  • Full delivery tracking

Publishing to a custom log

Section titled “Publishing to a custom log”

You can publish messages directly to a custom topic using the customGateway(...) API.

Fluxzero.get()
    .customGateway("third-party-events")
    .sendAndForget(new AuditEntry("User login"));

This gives you full control to emit messages that won’t show up in the main event log — ideal for isolating workflows, logs, or side effects.

Controlling retention

Section titled “Controlling retention”

Each log (including custom ones) can have its own retention policy. By default, messages are retained according to the global retention settings — but you can override this per topic.

Fluxzero.get()
    .customGateway("third-party-events")
    .setRetentionTime(Duration.ofDays(90));

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