We now support SpEL expressions in routing targets for events to be externalized. Introduced a BrokerRouting.getTarget(Object) overload to allow access to the event object in the SpEL expression. To support those, event externalizers will have to call that method where they previously called ….getTarget().
EventExternalizationConfiguration now exposes a ….headers(Class<T>, Function<T, Map<String, Object>) to allow to define a function that extracts headers from the event that are supposed to added to the message to be sent out. The Kafka and AMQP implementations have been augmented to consider those configurations.
Furthermore, if the mapping step prior to the externalization creates a Spring Message<?>, we add routing information as fallback and send it out as is.
DelegatingEventExternalizer.externalize(…) flavors now return a CompletableFuture to allow the target APIs to use asynchronous message sending and to transparently return a result from those invocations.
We now expose spring.modulith.events.externalization.enabled that can be set to false to disable the event externalization completely. Useful in test cases, for example.
We now allow externalizing application events to a variety of message brokers through the addition of Spring Modulith modules for Kafka, AMQP and JMS to a user project's classpath. Which events shall be externalized and how they're supposed to be routed to the message broker can be configured through either annotations or via a configuration API declared as Spring bean.
In case Jackson is on the classpath, we also add auto-configuration to use a Boot-configured ObjectMapper instance with the corresponding message broker client APIs to properly serialize and deserialize messages to JSON.
Introduce a new spring-modulith-events-api artifact to contain types that are supposed to be used by application code to deal with event publications. `EventPublication` was moved into that artifact and got everything non infrastructure related extracted from it's previous incarnation. That in turn has been renamed to `TargetEventPublication`.
`CompletedEventPublications` exposes API to allow purging completed publications either by a given predicate or age (in `Duration`). The interface is implemented by `DefaultEventPublicationRegistry` and thus subject for dependency injection into user code. It primarily delegates to the corresponding methods on `EventPublicationRepository` adapting the given `Duration`s to the `Clock` instance already held internally.
`IncompleteEventPublications` allows triggering the re-submission of incomplete publications by the same criteria as `CEP`. The interface is implemented by `PersistentApplicationEventMulticaster` and this subject for dependency injection into user code.
`EventPublicationRepository` now also allows publications to be deleted by identifiers. The existing implementations have been adapted and batch the requests for every 100 identifiers to prevent a list too large to run into limitations of the underlying data store.
Polished transactional metadata declaration in JPA- and MongoDB-based repository implementations.
Tightened nullability expressions here and there.
