spring - 执行时间响应式编程

Question

这是在响应式(Reactive)编程中找到方法( getFavouriteDetails() )的执行时间的理想方法吗？

public List<Favourites> getFavouriteDetails(String userId){
    userService.getFavorites(userId) 
               .flatMap(favoriteService::getDetails) 
               .switchIfEmpty(suggestionService.getSuggestions()) 
               .take(5) 
               .publishOn(UiUtils.uiThreadScheduler()) 
               .subscribe(uiList::show, UiUtils::errorPopup)
               .flatMap(a -> Mono.subscriberContext().map(ctx -> {
                         log.info("Time taken : " + Duration.between(ctx.get(key), Instant.now()).toMillis() + " milliseconds.");
                         return a;
                     }))
               .subscriberContext(ctx -> ctx.put(key, Instant.now()))
}

Answer 1

两种方法可确保您仅在订阅时测量执行时间 -

使用 flatMapMany 在 Flux 周围包裹 Mono .这也返回一个 Flux 。

使用 AtomicReference，在 onSubscribe 中设置时间并在 doFinally 中记录耗时.

示例代码 -

timeFluxV1(getFavouriteDetails(userId)).subscribe(uiList::show, UiUtils::errorPopup);

timeFluxV1(getFavouriteDetails(userId)).subscribe(uiList::show, UiUtils::errorPopup);
 
private <T>  Flux<T> timeFluxV1(Flux<T> flux) {
    return Mono.fromSupplier(System::nanoTime)
             .flatMapMany(time -> flux.doFinally(sig -> log.info("Time taken : " + TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - time) + " milliseconds.")));
}


private <T>  Flux<T> timeFluxV2(Flux<T> flux) {
    AtomicReference<Long> startTime = new AtomicReference<>();
    return flux.doOnSubscribe(x -> startTime.set(System.nanoTime()))
            .doFinally(x -> log.info("Time taken : " + TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - startTime.get()) + " milliseconds."));
}

public Flux<Favourites> getFavouriteDetails(String userId) {
    return userService.getFavorites(userId)
               .flatMap(favoriteService::getDetails) 
               .switchIfEmpty(suggestionService.getSuggestions()) 
               .take(5) 
               .publishOn(UiUtils.uiThreadScheduler());
}