Проект на Java и библиотеке Reactor - а как же тесты?

Transcript

1. Проект на java и REACtor Kirill Merkushev а как же тесты?
2. 2 Kirill Merkushev Open Source aerokube.com JAVA Go sr. Java Engineer Vivy gmbh BERlin ex. Yandex
3. 3 Platform for new age of communication between Patients, Doctors and Insurances
4. 4 destroyer monolith as mvp document requestS vaccinations checkups
5. 5 Non-scalable Development testing load
6. 6 microservices? vaccinations data checkups reminders document request
7. 7 communication? how to build
8. 8 WE HAVESLA
9. 9 communication high level low level
10. 10 Predictable extensible reliable e
11. 11 architecture
12. 12 direct communication?
13. 13 event sourcing
14. 14 implementation
15. 15 Reactor
16. 16 service.getUser(id) .filter(permissionsService!::allowed) .flatMap(user !-> service .fetchDocumentRequests(user.getId()) .zipWith(logService!::reportAction) ) .doOnError(logService!::reportFail) .onErrorReturn( RateLimitException.class, status(TOO_MANY_REQUESTS).build() ) .onErrorReturn(status(INTERNAL_SERVER_ERROR).build()); Reactor way
17. 17 how to test? how to debug?
18. 18 YOU won't WANT to use Reactor
19. 19 Until… YOU won't WANT to use Reactor
20. 20 PlanWhat we have how to follow use reactor safe
21. 21 Reactive manifesto www.reactivemanifesto.org Responsive Resilient Elastic Message Driven
22. 22 Non-Blocking With Back-pressure Responsive Resilient Elastic Message Driven Reactive manifesto
23. 23 Non-Blocking With Back-pressure Responsive Resilient Elastic Message Driven Reactive manifesto to consume resources only when active
24. 24 Reactive Streams
25. 25 publisher subscriber subscription Reactive Streams
26. 26 Reactive Streams implementation v8 Reactor
27. 27 Flux: 0..N mono: 0..1 Reactor
28. 28 stream: 0..N optional: 0..1 JDK8 ~
29. 29 Reactive Streams rxJava reactor Actors akka fp oop
30. 30 service.getUser(id) .filter(permissionsService!::allowed) .flatMap(user !-> service .fetchDocumentRequests(user.getId()) .zipWith(logService!::reportAction) ) .doOnError(logService!::reportFail) .onErrorReturn( RateLimitException.class, status(TOO_MANY_REQUESTS).build() ) .onErrorReturn(status(INTERNAL_SERVER_ERROR).build()); We have
31. 31 service.getUser(id) .filter(permissionsService!::allowed) .flatMap(user !-> service .fetchDocumentRequests(user.getId()) .zipWith(logService!::reportAction) ) .doOnError(logService!::reportFail) .onErrorReturn( RateLimitException.class, status(TOO_MANY_REQUESTS).build() ) .onErrorReturn(status(INTERNAL_SERVER_ERROR).build()); We have flow
32. 32 service.getUser(id) .filter(permissionsService!::allowed) .flatMap(user !-> service .fetchDocumentRequests(user.getId()) .zipWith(logService!::reportAction) ) .doOnError(logService!::reportFail) .onErrorReturn( RateLimitException.class, status(TOO_MANY_REQUESTS).build() ) .onErrorReturn(status(INTERNAL_SERVER_ERROR).build()); We have merge
33. 33 service.getUser(id) .filter(permissionsService!::allowed) .flatMap(user !-> service .fetchDocumentRequests(user.getId()) .zipWith(logService!::reportAction) ) .doOnError(logService!::reportFail) .onErrorReturn( RateLimitException.class, status(TOO_MANY_REQUESTS).build() ) .onErrorReturn(status(INTERNAL_SERVER_ERROR).build()); We have Error handling
34. 34 Concurrent HERE Have back-pressure Declarative Have to get used
35. 35 Concurrent HERE Have back-pressure Declarative Have to get used Where layers? HOW TO TEST? HOW TO DEBUG?
36. 36 how to follow
37. 37 Layers service.getUser(id) permissionsService!::allowed logService!::reportFail logService!::reportAction
38. 38 Layers service.getUser(id) permissionsService!::allowed logService!::reportFail logService!::reportAction doOnError onErrorReturn Mono<User> Mono<Void>
39. 39 service.getUser(id) .filter(permissionsService!::allowed) .flatMap(user !-> service .fetchDocumentRequests(user.getId()) .zipWith(logService!::reportAction) ) .doOnError(logService!::reportFail) .onErrorReturn( RateLimitException.class, status(TOO_MANY_REQUESTS).build() ) .onErrorReturn(status(INTERNAL_SERVER_ERROR).build());
40. 40 Unhandled exception at reactor.util.Loggers$Slf4JLogger.error(Loggers.java:295) at reactor.core.publisher.SignalLogger.lambda$onErrorCall$5(SignalLogger.java:296) at reactor.core.publisher.FluxPeekFuseable$PeekFuseableSubscriber.onError(FluxPeekFuseable.java:219) at reactor.core.publisher.FluxMapFuseable$MapFuseableSubscriber.onError(FluxMapFuseable.java:134) at reactor.core.publisher.MonoCollectList$MonoBufferAllSubscriber.onError(MonoCollectList.java:107) at reactor.core.publisher.FluxMergeSequential$MergeSequentialMain.drain(FluxMergeSequential.java:341) at reactor.core.publisher.FluxMergeSequential$MergeSequentialMain.onError(FluxMergeSequential.java:242) at reactor.core.publisher.FluxFlattenIterable$FlattenIterableSubscriber.drainAsync(FluxFlattenIterable.java:305) onErrorReturn
41. 41 Checkpoints .checkpoint("allow-service") Assembly site of producer [reactor.core.publisher.MonoIgnoreThen] is identified by light checkpoint [allow- service]."description" : "allow-service" at reactor.util.Loggers$Slf4JLogger.error(Loggers.java:295) at reactor.core.publisher.SignalLogger.lambda$onErrorCall$5(SignalLogger.java:296) at reactor.core.publisher.FluxPeekFuseable$PeekFuseableSubscriber.onError(FluxPeekFuseable.java:219) at reactor.core.publisher.FluxMapFuseable$MapFuseableSubscriber.onError(FluxMapFuseable.java:134) at reactor.core.publisher.MonoCollectList$MonoBufferAllSubscriber.onError(MonoCollectList.java:107) at reactor.core.publisher.FluxMergeSequential$MergeSequentialMain.drain(FluxMergeSequential.java:341) at reactor.core.publisher.FluxMergeSequential$MergeSequentialMain.onError(FluxMergeSequential.java:242) at reactor.core.publisher.FluxFlattenIterable$FlattenIterableSubscriber.drainAsync(FluxFlattenIterable.java:305)
42. 42 DEBUG - logs .log("flow") 2018-11-21 17:59:23.285 INFO --- [ Test worker] flow : | request(unbounded) 2018-11-21 17:59:23.275 INFO --- [ Test worker] flow : | onSubscribe([Fuseable] FluxOnAssembly.OnAssemblySubscriber) 2018-11-21 17:59:23.291 ERROR --- [ Test worker] flow : | onError(java.lang.IllegalStateException)
43. 43 Use reactor safe
44. 44 hooks + tests Hooks.onOperatorDebug(); warn: performance impact Error has been observed by the following operator(s): |_ Mono.create(PublicEmergencyDataRepository.java:101) |_ MonoCreate$DefaultMonoSink.error(DefaultAsyncHandler.java:14) |_ Mono.onErrorMap(PublicEmergencyDataRepository.java:102) |_ Mono.then(PublicEmergencyDataRepository.java:103) |_ MonoCreate$DefaultMonoSink.error(DefaultAsyncHandler.java:14) |_ Mono.onErrorResume(PublicEmergencyDataService.java:70) |_ Mono.then(PublicEmergencyDataService.java:71) |_ Mono.then(UserEventLogConsumer.java:63) |_ Mono.defer(UserEventLogConsumer.java:29)
45. 45 unittest void expectTwoUsers(Flux<User> flux) { StepVerifier.create(flux) .expectNextMatches( user !-> user.getUsername().equals("swhite") ) .expectNextMatches( user !-> user.getUsername().equals("jpinkman") ) .expectComplete(); }
46. 46 cold/hot Mono.defer Mono.fromCallable Mono.just Mono.fromRunnable Flux.~ Mono.error
47. 47 cold/hot .switchIfEmpty(Mono.defer(() !-> service.random(id)) .delayUntil(!__ !-> accessLogService.unsuccess(id, headers)) .map(data !-> ResponseEntity.ok() .body(new ByteArrayResource(data)) ) ) heavY Delay
48. 48 cold/hot Mono.just(Files.readString(path)) immediately evaluated
49. 49 Retry .retryWhen(it -> it.delayElements(Duration.ofMillis(100)).take(2) ) .defaultIfEmpty(Collections.emptyList())
50. 50 Retry .retryWhen(Retry .anyOf(ServerException.class) .retryMax(5) .exponentialBackoff(Duration.ofMillis(100), Duration.ofMillis(500)) ) .onErrorMap(RetryExhaustedException.class, Throwable!::getCause) reactor-extra
51. 51 schedulers Mono.fromCallable(() !-> heavyIO(next)) .subscribeOn(Schedulers.parallel()) .log("heavy-io")
52. 52 schedulers Mono.fromCallable(() !-> heavyIO(next)) .subscribeOn(Schedulers.parallel()) .log("heavy-io") blocks Flux.interval .delay… .timeout…
53. 53 Drawbacks
54. 54 benefits only if fully non blocking already reactive
55. 55 fully non blocking already reactive or Mono.fromCallable Mono.fromRunnable .subscribeOn( Schedulers.elastic ) Mono!::block Flux…
56. 56 fully non blocking already reactive or Mono.fromCallable Mono.fromRunnable .subscribeOn( Schedulers.elastic ) Mono!::block Flux… or deal with leaks, race conditions, deadlocks
57. 57 Top 3 checkpoints, logs =========== TAKEAWAYS
58. 58 Top 3 checkpoints, logs unit tests, hooks =========== TAKEAWAYS
59. 59 Top 3 checkpoints, logs retries unit tests, hooks =========== TAKEAWAYS
60. 60 I am open to talk! github.com/lanwen t.me/lanwen kirill merkushev @delnariel