Java logging example 1

example1.java

@RestController
public class ExampleController {
    private static final Logger log = LoggerFactory.getLogger(ExampleController.class);

    @GetMapping("/example1")
    public Mono<String> example1(@RequestHeader("X-Request-Id") String requestId) {
        return
            doSomeStuff()
                .contextWrite(context -> context.put("requestId", requestId))
            ;
    }
    
    private Mono<String> doSomeStuff() {
        return
            Mono.just("Some data")
                .doOnEach(signal -> {
                    if (signal.isOnNext()) {
                        var requestId = (String) signal.getContextView().get("requestId");

                        log.info("This is request id: {}", requestId);
                    }
                });
    }
}