Package org.axonframework.messaging.eventhandling.tracing

Class TracingEventSink

java.lang.Object
org.axonframework.messaging.eventhandling.tracing.TracingEventSink
All Implemented Interfaces:
DescribableComponent, EventSink
@Internal public final class TracingEventSink extends Object implements EventSink
Delegating EventSink decorator that opens tracing spans around event publication.

Publication is traced with a short-lived producer span per event, during which the span's tracing context is injected into the event's metadata so a downstream handler can continue the trace.

This decorator is registered by MessagingTracingConfigurationEnhancer; it is never instantiated directly by applications.

Since:
5.3.0
Author:
Mateusz Nowak

  • Constructor Details

    • TracingEventSink

      public TracingEventSink(EventSink delegate, SpanFactory spanFactory)
      Initializes a tracing EventSink wrapping the given delegate, obtaining spans from the given spanFactory.
      Parameters:
      delegate - the event sink to delegate to
      spanFactory - the factory producing the tracing spans

  • Method Details

    • publish

      public CompletableFuture<Void> publish(@Nullable ProcessingContext context, List<? extends EventMessage> events)
      Description copied from interface: EventSink
      Publishes the given events within the given context, when present.

      When present, the post invocation phase is used to publish the events. As a consequence, the resulting CompletableFuture completes when the events are staged in that phase.

      When no ProcessingContext is provided, implementers of this interface may choose to create a ProcessingContext when necessary.

      Specified by:
      publish in interface EventSink
      Parameters:
      context - The processing context, if any, to publish the given events in.
      events - The events to publish in this sink.
      Returns:
      A CompletableFuture of Void. When this completes and a non-null context was given, this means the events have been successfully staged. When a null context was provided, successful completion of this future means the events were published.

    • describeTo

      public void describeTo(ComponentDescriptor descriptor)
      Description copied from interface: DescribableComponent
      Describe the properties of this DescribableComponent with the given descriptor.

      Components should call the appropriate describeProperty methods on the descriptor to register their properties. The descriptor is responsible for determining how these properties are formatted and structured in the final output.

      Best Practices: As a general rule, all relevant fields of a DescribableComponent implementation should be described in this method. However, developers have discretion to include only the fields that make sense in the context. Not every field may be meaningful for description purposes, especially internal implementation details. Furthermore, components might want to expose different information based on their current state. The final decision on what properties to include lies with the person implementing the describeTo method, who should focus on providing information that is useful for understanding the component's configuration and state.

      Example implementation: 

       public void describeTo(ComponentDescriptor descriptor) {
     descriptor.describeProperty("name", this.name);
     descriptor.describeProperty("enabled", this.enabled);
     descriptor.describeProperty("configuration", this.configuration); // A nested component
     descriptor.describeProperty("handlers", this.eventHandlers);      // A collection
 }
      Specified by:
      describeTo in interface DescribableComponent
      Parameters:
      descriptor - The component descriptor to describe this DescribableComponentn its properties in.