Support Spring MVC functional controller

[haupv1m]

Feature Description

From Spring 5.2, functional endpoint approach is already available on Spring MVC. However, currently, newrelic-java agent only support Spring MVC annotation controller

https://docs.spring.io/spring-framework/reference/web/webmvc-functional.html

Describe Alternatives

Support Spring MVC HandlerFunction as Web request handler

(Migrate to Jira)

[workato-integration]

https://issues.newrelic.com/browse/NEWRELIC-4046

[jtduffy]

The existing instrumentation supports this pattern of controllers with RouterFunctions and registered handlers: For example:

public class Greeting2Router {
    @Bean
    public RouterFunction<ServerResponse> routeGet(Greeting2Handler greetingHandler) {
        return RouterFunctions
                .route(GET("/greet2").and(accept(MediaType.APPLICATION_JSON)), greetingHandler::hello);
    }
}


public class Greeting2Handler {
    public Mono<ServerResponse> hello(ServerRequest request) {
        return ServerResponse.ok().contentType(MediaType.APPLICATION_JSON)
                .body(BodyInserters.fromValue(new Greeting("hello", "world")));
    }
}