SpringDocs - Customize GroupedApi in external Module

OpenApiConfiguration_ModuleX.java

@Configuration
public class OpenApiConfiguration_ModuleX {
   
   @Bean("ModXApiDefinitionBuilder")
    public GroupedOpenApi.Builder adminApiDefinitionBuilder(@Value("${info.app.version:unknown}") String version) {
        return GroupedOpenApi.builder()
                .group("My API")
                .addOpenApiCustomizer(openApi -> {
                    openApi.info(new Info().title("My API").version(version));
                })
                .pathsToMatch("/api/x/**");
    }

    @Bean("ModXApiDefinition")
    public GroupedOpenApi adminApiDefinition(@Qualifier("ModXApiDefinitionBuilder") GroupedOpenApi.Builder builder) {
        return builder.build();
    }

}

OpenApiConfiguration_ModuleY.java

@Configuration
public class OpenApiConfiguration_ModuleY implements InitializingBean {
  
    private @Autowired(required = false)  @Qualifier("ModXApiDefinitionBuilder") GroupedOpenApi.Builder builder;
  
  
    @Override
    public void afterPropertiesSet() {
        if (Objects.nonNull(this.builder)) {
            builder.addOperationCustomizer((ops, method)
                    -> ops.addParametersItem(new HeaderParameter().name("X-Application")));
        }
    }
  
}

Example how to extend an API defined in a different module with additional parameters (in this case a header)