Context

Debezium Embedded Engine supports a PostProcessor interface that allows developers to manipulate or transform change events before they are dispatched to the application via the .notifying() callback.

This mechanism is useful for:

• Filtering or modifying event payloads

• Injecting metadata

• Performing lightweight enrichment or data cleansing

To provide a consistent developer experience and support advanced transformation needs, the Quarkus extension should expose this capability via an annotation-based handler.

Decision

Introduce a CDI-compatible annotation: @DebeziumPostProcessor.

This annotation identifies a method that should be invoked as a post-processing step for each change event emitted by the engine. The method must accept the event key and value as parameters.

Example:

import io.debezium.engine.InsertEvent;
import jakarta.enterprise.context.ApplicationScoped;

@ApplicationScoped  
class CustomPostProcessor {  
  
    @DebeziumPostProcessor()  
    public void process(Object key, Struct value) {
        /// some logic to apply
    }
    
}

Consequences

• The extension must intercept and register a post-processor during engine configuration.

• The annotated method must be discovered at build time and invoked at runtime with proper parameter binding.

• Only one post-processor is supported per engine; multiple annotations must trigger a build-time validation error.

• The processor method must not throw exceptions; failures should be logged and suppressed.

References:

Debezium Design Document: https://github.com/debezium/debezium-design-documents/pull/16