Spring WebFlux Block Hound Tells Blocking State - spring-webflux

Question

I'm new in spring flux trying to understand blocking system of spring flux.
When I execute the controller first method only then everything goes well.
But when I execute the second method only I got block statement and also not fetch data this way.
My Controller
#GetMapping("/test")
public Mono<Users> test1() {
return redisUtils.findByHash("users", "26", Users.class); // 1
return userService.findByEmail("a#a.com"); //2
}
My Service
#Override
public Mono<Users> findByEmail(String email) {
return redisUtils.findByHash(RedisKeys.USERS, "26", Users.class);
}
Redis Utility Methods
public <T> Mono<T> findByHash(String baseKey, String key, Class<T> clazz) {
return reactiveRedisTemplate.opsForHash().get(baseKey, key)
.flatMap(x -> {
try {
return Mono.just(objectMapper.convertValue(x, clazz));
} catch (IllegalArgumentException e) {
e.printStackTrace();
}
return Mono.empty();
});
}
block hound logs
reactor.blockhound.BlockingOperationError: Blocking call! sun.misc.Unsafe#park
at sun.misc.Unsafe.park(Unsafe.java) ~[na:1.8.0_281]
Suppressed: reactor.core.publisher.FluxOnAssembly$OnAssemblyException:
Error has been observed at the following site(s):
|_ checkpoint ⇢ Handler com.caretap.docapp.test.TestController#test1() [DispatcherHandler]
|_ checkpoint ⇢ org.springframework.web.cors.reactive.CorsWebFilter [DefaultWebFilterChain]
|_ checkpoint ⇢ org.springframework.security.web.server.authorization.AuthorizationWebFilter [DefaultWebFilterChain]
|_ checkpoint ⇢ org.springframework.security.web.server.authorization.ExceptionTranslationWebFilter [DefaultWebFilterChain]
|_ checkpoint ⇢ org.springframework.security.web.server.authentication.logout.LogoutWebFilter [DefaultWebFilterChain]
|_ checkpoint ⇢ org.springframework.security.web.server.savedrequest.ServerRequestCacheWebFilter [DefaultWebFilterChain]
|_ checkpoint ⇢ org.springframework.security.web.server.context.SecurityContextServerWebExchangeWebFilter [DefaultWebFilterChain]
|_ checkpoint ⇢ org.springframework.security.web.server.authentication.AuthenticationWebFilter [DefaultWebFilterChain]
|_ checkpoint ⇢ org.springframework.security.web.server.context.ReactorContextWebFilter [DefaultWebFilterChain]
|_ checkpoint ⇢ org.springframework.security.web.server.header.HttpHeaderWriterWebFilter [DefaultWebFilterChain]
|_ checkpoint ⇢ org.springframework.security.config.web.server.ServerHttpSecurity$ServerWebExchangeReactorContextWebFilter [DefaultWebFilterChain]
|_ checkpoint ⇢ org.springframework.security.web.server.WebFilterChainProxy [DefaultWebFilterChain]
|_ checkpoint ⇢ HTTP GET "/auth/test" [ExceptionHandlingWebHandler]
Stack trace:
at sun.misc.Unsafe.park(Unsafe.java) ~[na:1.8.0_281]
at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175) ~[na:1.8.0_281]
at java.util.concurrent.CompletableFuture$Signaller.block(CompletableFuture.java:1707) ~[na:1.8.0_281]
at java.util.concurrent.ForkJoinPool.managedBlock(ForkJoinPool.java:3334) ~[na:1.8.0_281]
at java.util.concurrent.CompletableFuture.waitingGet(CompletableFuture.java:1742) ~[na:1.8.0_281]
at java.util.concurrent.CompletableFuture.get(CompletableFuture.java:1908) ~[na:1.8.0_281]
at io.lettuce.core.DefaultConnectionFuture.get(DefaultConnectionFuture.java:69) ~[lettuce-core-6.0.2.RELEASE.jar:6.0.2.RELEASE]
at io.lettuce.core.AbstractRedisClient.getConnection(AbstractRedisClient.java:315) ~[lettuce-core-6.0.2.RELEASE.jar:6.0.2.RELEASE]
at io.lettuce.core.RedisClient.connect(RedisClient.java:211) ~[lettuce-core-6.0.2.RELEASE.jar:6.0.2.RELEASE]
at org.springframework.data.redis.connection.lettuce.StandaloneConnectionProvider.lambda$getConnection$1(StandaloneConnectionProvider.java:115) ~[spring-data-redis-2.4.3.jar:2.4.3]
at java.util.Optional.orElseGet(Optional.java:267) ~[na:1.8.0_281]
at org.springframework.data.redis.connection.lettuce.StandaloneConnectionProvider.getConnection(StandaloneConnectionProvider.java:115) ~[spring-data-redis-2.4.3.jar:2.4.3]
at org.springframework.data.redis.connection.lettuce.LettuceConnectionFactory$ExceptionTranslatingConnectionProvider.getConnection(LettuceConnectionFactory.java:1459) ~[spring-data-redis-2.4.3.jar:2.4.3]
at org.springframework.data.redis.connection.lettuce.LettuceConnectionFactory$SharedConnection.getNativeConnection(LettuceConnectionFactory.java:1247) ~[spring-data-redis-2.4.3.jar:2.4.3]
at org.springframework.data.redis.connection.lettuce.LettuceConnectionFactory$SharedConnection.getConnection(LettuceConnectionFactory.java:1230) ~[spring-data-redis-2.4.3.jar:2.4.3]
at org.springframework.data.redis.connection.lettuce.LettuceConnectionFactory.getSharedReactiveConnection(LettuceConnectionFactory.java:989) ~[spring-data-redis-2.4.3.jar:2.4.3]
at org.springframework.data.redis.connection.lettuce.LettuceConnectionFactory.getReactiveConnection(LettuceConnectionFactory.java:445) ~[spring-data-redis-2.4.3.jar:2.4.3]
at org.springframework.data.redis.connection.lettuce.LettuceConnectionFactory.getReactiveConnection(LettuceConnectionFactory.java:98) ~[spring-data-redis-2.4.3.jar:2.4.3]
at org.springframework.data.redis.core.ReactiveRedisTemplate.lambda$doInConnection$0(ReactiveRedisTemplate.java:198) ~[spring-data-redis-2.4.3.jar:2.4.3]
at reactor.core.publisher.MonoSupplier.call(MonoSupplier.java:85) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.FluxUsingWhen.subscribe(FluxUsingWhen.java:80) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:64) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.MonoUsingWhen.subscribe(MonoUsingWhen.java:87) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:64) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.MonoFlatMap$FlatMapMain.onNext(MonoFlatMap.java:157) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onNext(FluxSwitchIfEmpty.java:73) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.FluxMapFuseable$MapFuseableSubscriber.onNext(FluxMapFuseable.java:127) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.Operators$MonoSubscriber.complete(Operators.java:1789) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.MonoFlatMap$FlatMapInner.onNext(MonoFlatMap.java:249) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.Operators$MonoSubscriber.complete(Operators.java:1789) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.MonoFlatMap$FlatMapInner.onNext(MonoFlatMap.java:249) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.Operators$MonoSubscriber.complete(Operators.java:1789) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.MonoFlatMap$FlatMapInner.onNext(MonoFlatMap.java:249) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.FluxOnErrorResume$ResumeSubscriber.onNext(FluxOnErrorResume.java:79) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.Operators$MonoSubscriber.complete(Operators.java:1789) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.MonoIgnoreThen$ThenIgnoreMain.drain(MonoIgnoreThen.java:148) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.MonoIgnoreThen$ThenIgnoreMain.ignoreDone(MonoIgnoreThen.java:191) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.MonoIgnoreThen$ThenIgnoreInner.onComplete(MonoIgnoreThen.java:248) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.MonoPeekTerminal$MonoTerminalPeekSubscriber.onComplete(MonoPeekTerminal.java:299) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.MonoIgnoreElements$IgnoreElementsSubscriber.onComplete(MonoIgnoreElements.java:88) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.MonoIgnoreElements$IgnoreElementsSubscriber.onComplete(MonoIgnoreElements.java:88) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.Operators$MultiSubscriptionSubscriber.onComplete(Operators.java:2031) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.Operators$MonoSubscriber.complete(Operators.java:1790) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.MonoFlatMap$FlatMapInner.onNext(MonoFlatMap.java:249) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.FluxOnErrorResume$ResumeSubscriber.onNext(FluxOnErrorResume.java:79) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.Operators$MonoSubscriber.complete(Operators.java:1789) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.MonoIgnoreThen$ThenIgnoreMain.drain(MonoIgnoreThen.java:148) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.MonoIgnoreThen$ThenIgnoreMain.ignoreDone(MonoIgnoreThen.java:191) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.MonoIgnoreThen$ThenIgnoreInner.onComplete(MonoIgnoreThen.java:248) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.MonoPeekTerminal$MonoTerminalPeekSubscriber.onComplete(MonoPeekTerminal.java:299) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.Operators$MonoSubscriber.onComplete(Operators.java:1831) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.MonoIgnoreThen$ThenAcceptInner.onComplete(MonoIgnoreThen.java:323) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.FluxPeek$PeekSubscriber.onComplete(FluxPeek.java:259) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.MonoIgnoreElements$IgnoreElementsSubscriber.onComplete(MonoIgnoreElements.java:88) ~[reactor-core-3.4.2.jar:3.4.2]
at io.r2dbc.postgresql.util.FluxDiscardOnCancel$FluxDiscardOnCancelSubscriber.onComplete(FluxDiscardOnCancel.java:99) ~[r2dbc-postgresql-0.8.6.RELEASE.jar:0.8.6.RELEASE]
at reactor.core.publisher.Operators.complete(Operators.java:135) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.FluxEmpty.subscribe(FluxEmpty.java:41) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.FluxDefer.subscribe(FluxDefer.java:54) ~[reactor-core-3.4.2.jar:3.4.2]
at io.r2dbc.postgresql.util.FluxDiscardOnCancel.subscribe(FluxDiscardOnCancel.java:49) ~[r2dbc-postgresql-0.8.6.RELEASE.jar:0.8.6.RELEASE]
at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:64) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.MonoIgnoreThen$ThenIgnoreMain.drain(MonoIgnoreThen.java:154) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.MonoIgnoreThen$ThenIgnoreMain.ignoreDone(MonoIgnoreThen.java:191) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.MonoIgnoreThen$ThenIgnoreInner.onComplete(MonoIgnoreThen.java:248) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.MonoIgnoreElements$IgnoreElementsSubscriber.onComplete(MonoIgnoreElements.java:88) ~[reactor-core-3.4.2.jar:3.4.2]
at io.r2dbc.postgresql.util.FluxDiscardOnCancel$FluxDiscardOnCancelSubscriber.onComplete(FluxDiscardOnCancel.java:99) ~[r2dbc-postgresql-0.8.6.RELEASE.jar:0.8.6.RELEASE]
at reactor.core.publisher.MonoIgnoreElements$IgnoreElementsSubscriber.onComplete(MonoIgnoreElements.java:88) ~[reactor-core-3.4.2.jar:3.4.2]
at io.r2dbc.postgresql.util.FluxDiscardOnCancel$FluxDiscardOnCancelSubscriber.onComplete(FluxDiscardOnCancel.java:99) ~[r2dbc-postgresql-0.8.6.RELEASE.jar:0.8.6.RELEASE]
at io.r2dbc.postgresql.util.FluxDiscardOnCancel$FluxDiscardOnCancelSubscriber.onComplete(FluxDiscardOnCancel.java:99) ~[r2dbc-postgresql-0.8.6.RELEASE.jar:0.8.6.RELEASE]
at reactor.core.publisher.FluxHandle$HandleSubscriber.onComplete(FluxHandle.java:212) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.FluxCreate$BaseSink.complete(FluxCreate.java:439) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.FluxCreate$BufferAsyncSink.drain(FluxCreate.java:784) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.FluxCreate$BufferAsyncSink.complete(FluxCreate.java:732) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.FluxCreate$SerializedFluxSink.drainLoop(FluxCreate.java:240) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.FluxCreate$SerializedFluxSink.drain(FluxCreate.java:206) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.FluxCreate$SerializedFluxSink.complete(FluxCreate.java:197) ~[reactor-core-3.4.2.jar:3.4.2]
at io.r2dbc.postgresql.client.ReactorNettyClient$Conversation.complete(ReactorNettyClient.java:719) ~[r2dbc-postgresql-0.8.6.RELEASE.jar:0.8.6.RELEASE]
at io.r2dbc.postgresql.client.ReactorNettyClient$BackendMessageSubscriber.emit(ReactorNettyClient.java:984) ~[r2dbc-postgresql-0.8.6.RELEASE.jar:0.8.6.RELEASE]
at io.r2dbc.postgresql.client.ReactorNettyClient$BackendMessageSubscriber.onNext(ReactorNettyClient.java:860) ~[r2dbc-postgresql-0.8.6.RELEASE.jar:0.8.6.RELEASE]
at io.r2dbc.postgresql.client.ReactorNettyClient$BackendMessageSubscriber.onNext(ReactorNettyClient.java:767) ~[r2dbc-postgresql-0.8.6.RELEASE.jar:0.8.6.RELEASE]
at reactor.core.publisher.FluxHandle$HandleSubscriber.onNext(FluxHandle.java:118) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.FluxPeekFuseable$PeekConditionalSubscriber.onNext(FluxPeekFuseable.java:854) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.FluxMap$MapConditionalSubscriber.onNext(FluxMap.java:220) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.core.publisher.FluxMap$MapConditionalSubscriber.onNext(FluxMap.java:220) ~[reactor-core-3.4.2.jar:3.4.2]
at reactor.netty.channel.FluxReceive.drainReceiver(FluxReceive.java:267) ~[reactor-netty-core-1.0.3.jar:1.0.3]
at reactor.netty.channel.FluxReceive.onInboundNext(FluxReceive.java:377) ~[reactor-netty-core-1.0.3.jar:1.0.3]
at reactor.netty.channel.ChannelOperations.onInboundNext(ChannelOperations.java:381) ~[reactor-netty-core-1.0.3.jar:1.0.3]
at reactor.netty.channel.ChannelOperationsHandler.channelRead(ChannelOperationsHandler.java:94) ~[reactor-netty-core-1.0.3.jar:1.0.3]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) ~[netty-transport-4.1.58.Final.jar:4.1.58.Final]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365) ~[netty-transport-4.1.58.Final.jar:4.1.58.Final]
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357) ~[netty-transport-4.1.58.Final.jar:4.1.58.Final]
at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:324) ~[netty-codec-4.1.58.Final.jar:4.1.58.Final]
at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:296) ~[netty-codec-4.1.58.Final.jar:4.1.58.Final]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) ~[netty-transport-4.1.58.Final.jar:4.1.58.Final]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365) ~[netty-transport-4.1.58.Final.jar:4.1.58.Final]
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357) ~[netty-transport-4.1.58.Final.jar:4.1.58.Final]
at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1410) ~[netty-transport-4.1.58.Final.jar:4.1.58.Final]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) ~[netty-transport-4.1.58.Final.jar:4.1.58.Final]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365) ~[netty-transport-4.1.58.Final.jar:4.1.58.Final]
at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:919) ~[netty-transport-4.1.58.Final.jar:4.1.58.Final]
at io.netty.channel.epoll.AbstractEpollStreamChannel$EpollStreamUnsafe.epollInReady(AbstractEpollStreamChannel.java:795) ~[netty-transport-native-epoll-4.1.58.Final-linux-x86_64.jar:4.1.58.Final]
at io.netty.channel.epoll.EpollEventLoop.processReady(EpollEventLoop.java:480) ~[netty-transport-native-epoll-4.1.58.Final-linux-x86_64.jar:4.1.58.Final]
at io.netty.channel.epoll.EpollEventLoop.run(EpollEventLoop.java:378) ~[netty-transport-native-epoll-4.1.58.Final-linux-x86_64.jar:4.1.58.Final]
at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989) ~[netty-common-4.1.58.Final.jar:4.1.58.Final]
at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74) ~[netty-common-4.1.58.Final.jar:4.1.58.Final]
at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30) ~[netty-common-4.1.58.Final.jar:4.1.58.Final]
at java.lang.Thread.run(Thread.java:748) ~[na:1.8.0_281]