Actuator @ReadOperation on Flux cancels request after first element emitted #30095
Description
Problem:
@ReadOperation on a custom actuator endpoint returning Flux cancels the request after first element, the same code wrapped as a @GetMapping of a @RestController returns full response as expected. The workaround is to return Mono but its a bit weird.
Spring Boot Version 2.6.4 created via initializr with Webflux and Actuator
Code:
Actuator Endpoint
@Endpoint(id = "demo") @Component public class DemoEndpoint { @ReadOperation public Flux<String> test() { return Flux.range(0, 10).map(String::valueOf).log(); } } Demonstration Controller:
@RestController public class DemoRestController { @GetMapping public Flux<String> test(){ return Flux.range(0,10).map(String::valueOf).log(); } } See sample project attached.
curl localhost:8080 -> 0123456789
curl localhost:8080/actuator/demo -> 0
Expected behavior: 2nd call delivers 0123456789
Log:
2022-03-07 14:35:55.185 INFO 42052 --- [ctor-http-nio-2] reactor.Flux.MapFuseable.1 : | onSubscribe([Fuseable] FluxMapFuseable.MapFuseableSubscriber) 2022-03-07 14:35:55.186 INFO 42052 --- [ctor-http-nio-2] reactor.Flux.MapFuseable.1 : | request(1) 2022-03-07 14:35:55.187 INFO 42052 --- [ctor-http-nio-2] reactor.Flux.MapFuseable.1 : | onNext(0) 2022-03-07 14:35:55.201 INFO 42052 --- [ctor-http-nio-2] reactor.Flux.MapFuseable.1 : | request(127) 2022-03-07 14:35:55.201 INFO 42052 --- [ctor-http-nio-2] reactor.Flux.MapFuseable.1 : | onNext(1) 2022-03-07 14:35:55.201 INFO 42052 --- [ctor-http-nio-2] reactor.Flux.MapFuseable.1 : | onNext(2) 2022-03-07 14:35:55.202 INFO 42052 --- [ctor-http-nio-2] reactor.Flux.MapFuseable.1 : | onNext(3) 2022-03-07 14:35:55.202 INFO 42052 --- [ctor-http-nio-2] reactor.Flux.MapFuseable.1 : | onNext(4) 2022-03-07 14:35:55.202 INFO 42052 --- [ctor-http-nio-2] reactor.Flux.MapFuseable.1 : | onNext(5) 2022-03-07 14:35:55.202 INFO 42052 --- [ctor-http-nio-2] reactor.Flux.MapFuseable.1 : | onNext(6) 2022-03-07 14:35:55.203 INFO 42052 --- [ctor-http-nio-2] reactor.Flux.MapFuseable.1 : | onNext(7) 2022-03-07 14:35:55.203 INFO 42052 --- [ctor-http-nio-2] reactor.Flux.MapFuseable.1 : | onNext(8) 2022-03-07 14:35:55.203 INFO 42052 --- [ctor-http-nio-2] reactor.Flux.MapFuseable.1 : | onNext(9) 2022-03-07 14:35:55.203 INFO 42052 --- [ctor-http-nio-2] reactor.Flux.MapFuseable.1 : | onComplete() 2022-03-07 14:36:45.169 INFO 42052 --- [ctor-http-nio-3] reactor.Flux.MapFuseable.2 : | onSubscribe([Fuseable] FluxMapFuseable.MapFuseableSubscriber) 2022-03-07 14:36:45.169 INFO 42052 --- [ctor-http-nio-3] reactor.Flux.MapFuseable.2 : | request(unbounded) 2022-03-07 14:36:45.169 INFO 42052 --- [ctor-http-nio-3] reactor.Flux.MapFuseable.2 : | onNext(0) 2022-03-07 14:36:45.169 INFO 42052 --- [ctor-http-nio-3] reactor.Flux.MapFuseable.2 : | cancel()