reactive @Transactional fails with java.lang.IllegalStateException: block()/blockFirst()/blockLast() are blocking

[mikereiche]

From #1524.

The underlying issue is that TransactionInterceptor is being called instead of CouchbaseTransactionInterceptor. And it should be calling executeReactive() instead of execute().

@Service
class ScheduleService(
    private val reactiveOperations: ReactiveCouchbaseOperations
) {
    @Transactional
    fun saveScheduleWithTransaction(schedule: Schedule): Mono<Schedule> {
        return reactiveOperations.insertById(Schedule::class.java).one(schedule)
    }
}

java.lang.IllegalStateException: block()/blockFirst()/blockLast() are blocking, which is not supported in thread reactor-http-nio-3
	at reactor.core.publisher.BlockingSingleSubscriber.blockingGet(BlockingSingleSubscriber.java:83) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
	Suppressed: reactor.core.publisher.FluxOnAssembly$OnAssemblyException: 
Error has been observed at the following site(s):
	*__checkpoint ⇢ org.springframework.boot.actuate.metrics.web.reactive.server.MetricsWebFilter [DefaultWebFilterChain]
	*__checkpoint ⇢ HTTP POST "/schedule" [ExceptionHandlingWebHandler]
Original Stack Trace:
		at reactor.core.publisher.BlockingSingleSubscriber.blockingGet(BlockingSingleSubscriber.java:83) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.Mono.block(Mono.java:1675) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at org.springframework.data.couchbase.transaction.CouchbaseCallbackTransactionManager.handlePropagation(CouchbaseCallbackTransactionManager.java:191) ~[spring-data-couchbase-5.0.0-M5.jar:5.0.0-M5]
		at org.springframework.data.couchbase.transaction.CouchbaseCallbackTransactionManager.execute(CouchbaseCallbackTransactionManager.java:76) ~[spring-data-couchbase-5.0.0-M5.jar:5.0.0-M5]
		at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:417) ~[spring-tx-6.0.0-M5.jar:6.0.0-M5]
		at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:119) ~[spring-tx-6.0.0-M5.jar:6.0.0-M5]
		at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:184) ~[spring-aop-6.0.0-M5.jar:6.0.0-M5]
		at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:763) ~[spring-aop-6.0.0-M5.jar:6.0.0-M5]
		at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:708) ~[spring-aop-6.0.0-M5.jar:6.0.0-M5]
		at com.rbleuse.spring.reactive.couchbase.service.ScheduleService$$EnhancerBySpringCGLIB$$f091fb23.saveScheduleWithTransaction(<generated>) ~[main/:na]
		at com.rbleuse.spring.reactive.couchbase.handler.ScheduleHandler.createSchedule(ScheduleHandler.kt:20) ~[main/:na]

[mikereiche]

I was able to reproduce this. There are a couple issues - one is the call to block() in the non-blocking thread, and the other is that the TransactionInterceptor is used instead of the CouchbaseTransactionInterceptor.

If you create a ScheduleService that uses CouchbaseOperations instead of ReactiveOperations, then you will avoid the issue (I realize this isn't the same functionality, but it will let you try out transactions in spring).

[rbleuse]

Thanks for your suggestion !

[mikereiche]

I think you might be missing the @EnableTransactionManagement in your configuration class which extends AbstractCouchbaseConfiguration. (If it's in a different class, you might have transaction management, but it won't use the CouchbaseTransactionInterceptor, and the default TransactionInterceptor will attempt to execute reactive transactions as non-reactive transactions.

@Configuration
@EnableCouchbaseRepositories(...)
@EnableTransactionManagement // must be in the class that extends AbstractCouchbaseConfiguration
public class Config extends AbstractCouchbaseConfiguration {

If you print out the stacktrace in your @transactional method, it should show CouchbaseTransactionInterceptor in the stacktrace.
(new Exception(Thread.currentThread().getName())).printStackTrace();

java.lang.Exception: cb-txn-9
	at com.example.demo.UserService.insertReactive(UserService.java:24)
	at com.example.demo.UserService$$FastClassBySpringCGLIB$$86043490.invoke(<generated>)
	at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:218)
	at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:793)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163)
	at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:763)
	at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:123)
	at org.springframework.data.couchbase.transaction.CouchbaseTransactionInterceptor.lambda$invokeWithinTransaction$0(CouchbaseTransactionInterceptor.java:63)
	at org.springframework.data.couchbase.transaction.CouchbaseCallbackTransactionManager.lambda$executeNewReactiveTr

[rbleuse]

Thanks for investigating.

A couple of things :

I don't override AbstractCouchbaseConfiguration, instead I rely on the auto configuration with those parameters :

spring:
  couchbase:
    connection-string: couchbase://127.0.0.1
    username: admin
    password: password
  data:
    couchbase:
      bucket-name: test

And I declared a configuration like this :

@Configuration
@EnableTransactionManagement
class CouchbaseConfig {

    @Bean(BeanNames.COUCHBASE_TRANSACTION_MANAGER)
    fun couchbaseTransactionManager(clientFactory: CouchbaseClientFactory): CouchbaseCallbackTransactionManager {
        return CouchbaseCallbackTransactionManager(clientFactory)
    }
}

This is my set up with current exception.

Now I tried to follow your suggestion, I keep same code base but instead declare a config that extends AbstractCouchbaseConfiguration :

@Configuration
@EnableTransactionManagement
class CouchbaseConfig(
    private val properties: CouchbaseProperties
) : AbstractCouchbaseConfiguration() {
    override fun getConnectionString(): String {
        return properties.connectionString
    }

    override fun getUserName(): String {
        return properties.username
    }

    override fun getPassword(): String {
        return properties.password
    }

    override fun getBucketName(): String {
        return "test"
    }
}

By doing so, indeed as you mentioned I have to add allow-bean-definition-overriding: true else the app doesn't start at all :

The bean 'transactionInterceptor', defined in class path resource [com/rbleuse/spring/reactive/couchbase/config/CouchbaseConfig.class], could not be registered. A bean with that name has already been defined in class path resource [org/springframework/transaction/annotation/ProxyTransactionManagementConfiguration.class] and overriding is disabled.

Then after adding this configuration properties, the app starts well but I still have the same exception.
This exception occurs before entering my service saveScheduleWithTransaction function, annotated with @Transactional.
If I comment the annotation, my function is well executed (without transaction of course).

I can push my code on a dummy repo if you would like to investigate with my configuration

[mikereiche]

Thanks for your patience.
Yes, if you could make a repo that I could access to reproduce the issue that would help.
If you want to try something yourself - Maybe completely abandon the spring: properties and use only the CouchbaseConfig class - it will also need @EnableCouchbaseRepository. (all our testing is done with only the configuration class).

Then after adding this configuration properties, the app starts well but I still have the same exception.
This exception occurs before entering my service saveScheduleWithTransaction function, annotated with @transactional.

I lost track - which exception? The block() exception? Is CouchbaseTransactionInterceptor in the stack trace?

[rbleuse]

I lost track - which exception? The block() exception? Is CouchbaseTransactionInterceptor in the stack trace?

Yes the blocking exception, a bit different stack trace now but still referring to CouchbaseCallbackTransactionManager.java:191 :

stack trace

java.lang.IllegalStateException: block()/blockFirst()/blockLast() are blocking, which is not supported in thread reactor-http-nio-3
	at reactor.core.publisher.BlockingSingleSubscriber.blockingGet(BlockingSingleSubscriber.java:83) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
	Suppressed: reactor.core.publisher.FluxOnAssembly$OnAssemblyException: 
Error has been observed at the following site(s):
	*__checkpoint ⇢ org.springframework.boot.actuate.metrics.web.reactive.server.MetricsWebFilter [DefaultWebFilterChain]
	*__checkpoint ⇢ HTTP POST "/schedule" [ExceptionHandlingWebHandler]
Original Stack Trace:
		at reactor.core.publisher.BlockingSingleSubscriber.blockingGet(BlockingSingleSubscriber.java:83) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.Mono.block(Mono.java:1675) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at org.springframework.data.couchbase.transaction.CouchbaseCallbackTransactionManager.handlePropagation(CouchbaseCallbackTransactionManager.java:191) ~[spring-data-couchbase-5.0.0-M5.jar:5.0.0-M5]
		at org.springframework.data.couchbase.transaction.CouchbaseCallbackTransactionManager.lambda$executeReactive$0(CouchbaseCallbackTransactionManager.java:91) ~[spring-data-couchbase-5.0.0-M5.jar:5.0.0-M5]
		at reactor.core.publisher.FluxDefer.subscribe(FluxDefer.java:46) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:64) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.MonoFlatMap$FlatMapMain.onNext(MonoFlatMap.java:157) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onNext(FluxSwitchIfEmpty.java:74) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.MonoNext$NextSubscriber.onNext(MonoNext.java:82) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.FluxConcatMapNoPrefetch$FluxConcatMapNoPrefetchSubscriber.innerNext(FluxConcatMapNoPrefetch.java:258) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.FluxConcatMap$ConcatMapInner.onNext(FluxConcatMap.java:863) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.FluxMap$MapSubscriber.onNext(FluxMap.java:122) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.FluxPeek$PeekSubscriber.onNext(FluxPeek.java:200) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.MonoNext$NextSubscriber.onNext(MonoNext.java:82) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.FluxConcatArray$ConcatArraySubscriber.onNext(FluxConcatArray.java:201) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.MonoNext$NextSubscriber.onNext(MonoNext.java:82) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.FluxConcatArray$ConcatArraySubscriber.onNext(FluxConcatArray.java:201) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.Operators$ScalarSubscription.request(Operators.java:2398) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.FluxConcatArray$ConcatArraySubscriber.request(FluxConcatArray.java:276) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.MonoNext$NextSubscriber.request(MonoNext.java:108) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.FluxConcatArray$ConcatArraySubscriber.request(FluxConcatArray.java:276) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.MonoNext$NextSubscriber.request(MonoNext.java:108) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.FluxPeek$PeekSubscriber.request(FluxPeek.java:138) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.FluxMap$MapSubscriber.request(FluxMap.java:164) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.Operators$MultiSubscriptionSubscriber.request(Operators.java:2158) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.FluxConcatMapNoPrefetch$FluxConcatMapNoPrefetchSubscriber.request(FluxConcatMapNoPrefetch.java:338) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.MonoNext$NextSubscriber.request(MonoNext.java:108) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.Operators$MultiSubscriptionSubscriber.set(Operators.java:2194) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.Operators$MultiSubscriptionSubscriber.onSubscribe(Operators.java:2068) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.MonoNext$NextSubscriber.onSubscribe(MonoNext.java:70) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.FluxConcatMapNoPrefetch$FluxConcatMapNoPrefetchSubscriber.onSubscribe(FluxConcatMapNoPrefetch.java:164) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.FluxIterable.subscribe(FluxIterable.java:165) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.FluxIterable.subscribe(FluxIterable.java:87) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:64) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:64) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:64) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.Mono.subscribe(Mono.java:4321) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.MonoIgnoreThen$ThenIgnoreMain.subscribeNext(MonoIgnoreThen.java:263) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.MonoIgnoreThen.subscribe(MonoIgnoreThen.java:51) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:64) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.MonoDeferContextual.subscribe(MonoDeferContextual.java:55) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.netty.http.server.HttpServer$HttpServerHandle.onStateChange(HttpServer.java:967) ~[reactor-netty-http-1.1.0-M4.jar:1.1.0-M4]
		at reactor.netty.ReactorNetty$CompositeConnectionObserver.onStateChange(ReactorNetty.java:677) ~[reactor-netty-core-1.1.0-M4.jar:1.1.0-M4]
		at reactor.netty.transport.ServerTransport$ChildObserver.onStateChange(ServerTransport.java:478) ~[reactor-netty-core-1.1.0-M4.jar:1.1.0-M4]
		at reactor.netty.http.server.HttpServerOperations.onInboundNext(HttpServerOperations.java:570) ~[reactor-netty-http-1.1.0-M4.jar:1.1.0-M4]
		at reactor.netty.channel.ChannelOperationsHandler.channelRead(ChannelOperationsHandler.java:93) ~[reactor-netty-core-1.1.0-M4.jar:1.1.0-M4]
		at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) ~[netty-transport-4.1.79.Final.jar:4.1.79.Final]
		at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365) ~[netty-transport-4.1.79.Final.jar:4.1.79.Final]
		at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357) ~[netty-transport-4.1.79.Final.jar:4.1.79.Final]
		at reactor.netty.http.server.HttpTrafficHandler.channelRead(HttpTrafficHandler.java:222) ~[reactor-netty-http-1.1.0-M4.jar:1.1.0-M4]
		at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) ~[netty-transport-4.1.79.Final.jar:4.1.79.Final]
		at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365) ~[netty-transport-4.1.79.Final.jar:4.1.79.Final]
		at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357) ~[netty-transport-4.1.79.Final.jar:4.1.79.Final]
		at io.netty.channel.CombinedChannelDuplexHandler$DelegatingChannelHandlerContext.fireChannelRead(CombinedChannelDuplexHandler.java:436) ~[netty-transport-4.1.79.Final.jar:4.1.79.Final]
		at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:327) ~[netty-codec-4.1.79.Final.jar:4.1.79.Final]
		at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:299) ~[netty-codec-4.1.79.Final.jar:4.1.79.Final]
		at io.netty.channel.CombinedChannelDuplexHandler.channelRead(CombinedChannelDuplexHandler.java:251) ~[netty-transport-4.1.79.Final.jar:4.1.79.Final]
		at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) ~[netty-transport-4.1.79.Final.jar:4.1.79.Final]
		at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365) ~[netty-transport-4.1.79.Final.jar:4.1.79.Final]
		at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357) ~[netty-transport-4.1.79.Final.jar:4.1.79.Final]
		at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1410) ~[netty-transport-4.1.79.Final.jar:4.1.79.Final]
		at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) ~[netty-transport-4.1.79.Final.jar:4.1.79.Final]
		at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365) ~[netty-transport-4.1.79.Final.jar:4.1.79.Final]
		at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:919) ~[netty-transport-4.1.79.Final.jar:4.1.79.Final]
		at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:166) ~[netty-transport-4.1.79.Final.jar:4.1.79.Final]
		at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:722) ~[netty-transport-4.1.79.Final.jar:4.1.79.Final]
		at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:658) ~[netty-transport-4.1.79.Final.jar:4.1.79.Final]
		at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:584) ~[netty-transport-4.1.79.Final.jar:4.1.79.Final]
		at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:496) ~[netty-transport-4.1.79.Final.jar:4.1.79.Final]
		at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:997) ~[netty-common-4.1.79.Final.jar:4.1.79.Final]
		at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74) ~[netty-common-4.1.79.Final.jar:4.1.79.Final]
		at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30) ~[netty-common-4.1.79.Final.jar:4.1.79.Final]
		at java.base/java.lang.Thread.run(Thread.java:833) ~[na:na]

I'll push my code on a reroducible repo

[rbleuse]

Here it is : https://github.com/rbleuse/spring-reactive-couchbase
It's using spring boot 3.0.0-M4 with latest couchbase snapshot

Just run the spring boot app and a curl curl --location --request POST 'localhost:8080/schedule'

By the way, saving with a repository (without transaction) doesn't work since 5.0.0-M5 (works fine with M4), I added comments about it, if you want to investigate.
Thanks for your help

[mikereiche]

 		at org.springframework.data.couchbase.transaction.CouchbaseCallbackTransactionManager.handlePropagation(CouchbaseCallbackTransactionManager.java:191) ~[spring-data-couchbase-5.0.0-M5.jar:5.0.0-M5]
		at org.springframework.data.couchbase.transaction.CouchbaseCallbackTransactionManager.lambda$executeReactive$0(CouchbaseCallbackTransactionManager.java:91) ~[spring-data-couchbase-5.0.0-M5.jar:5.0.0-M5]

Ok - I can fix this.

[mikereiche]

@rbleuse - this should work now. I tried it on your project.

[rbleuse]

@mikereiche indeed now transaction works with latest snapshot !

In my dummy repo there's a second exception that is showcased but was commented.
https://github.com/rbleuse/spring-reactive-couchbase/blob/main/src/main/kotlin/com/rbleuse/spring/reactive/couchbase/handler/ScheduleHandler.kt#L21
A simple repository.save(schedule) gives me this exception (still occurs with latest snapshot) :

stack trace

java.lang.IllegalStateException: block()/blockFirst()/blockLast() are blocking, which is not supported in thread reactor-http-nio-3
	at reactor.core.publisher.BlockingSingleSubscriber.blockingGet(BlockingSingleSubscriber.java:83) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
	Suppressed: reactor.core.publisher.FluxOnAssembly$OnAssemblyException: 
Error has been observed at the following site(s):
	*__checkpoint ⇢ org.springframework.boot.actuate.metrics.web.reactive.server.MetricsWebFilter [DefaultWebFilterChain]
	*__checkpoint ⇢ HTTP POST "/schedule" [ExceptionHandlingWebHandler]
Original Stack Trace:
		at reactor.core.publisher.BlockingSingleSubscriber.blockingGet(BlockingSingleSubscriber.java:83) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.Mono.block(Mono.java:1675) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at org.springframework.data.couchbase.core.ReactiveCouchbaseTemplate.save(ReactiveCouchbaseTemplate.java:94) ~[spring-data-couchbase-5.0.0-SNAPSHOT.jar:5.0.0-SNAPSHOT]
		at org.springframework.data.couchbase.repository.support.SimpleReactiveCouchbaseRepository.save(SimpleReactiveCouchbaseRepository.java:100) ~[spring-data-couchbase-5.0.0-SNAPSHOT.jar:5.0.0-SNAPSHOT]
		at org.springframework.data.couchbase.repository.support.SimpleReactiveCouchbaseRepository.save(SimpleReactiveCouchbaseRepository.java:79) ~[spring-data-couchbase-5.0.0-SNAPSHOT.jar:5.0.0-SNAPSHOT]
		at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
		at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77) ~[na:na]
		at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
		at java.base/java.lang.reflect.Method.invoke(Method.java:568) ~[na:na]
		at org.springframework.data.repository.core.support.RepositoryMethodInvoker$RepositoryFragmentMethodInvoker.lambda$new$0(RepositoryMethodInvoker.java:289) ~[spring-data-commons-3.0.0-M5.jar:3.0.0-M5]
		at org.springframework.data.repository.core.support.RepositoryMethodInvoker.doInvoke(RepositoryMethodInvoker.java:137) ~[spring-data-commons-3.0.0-M5.jar:3.0.0-M5]
		at org.springframework.data.repository.core.support.RepositoryMethodInvoker.invoke(RepositoryMethodInvoker.java:121) ~[spring-data-commons-3.0.0-M5.jar:3.0.0-M5]
		at org.springframework.data.repository.core.support.RepositoryComposition$RepositoryFragments.invoke(RepositoryComposition.java:516) ~[spring-data-commons-3.0.0-M5.jar:3.0.0-M5]
		at org.springframework.data.repository.core.support.RepositoryComposition.invoke(RepositoryComposition.java:285) ~[spring-data-commons-3.0.0-M5.jar:3.0.0-M5]
		at org.springframework.data.repository.core.support.RepositoryFactorySupport$ImplementationMethodExecutionInterceptor.invoke(RepositoryFactorySupport.java:628) ~[spring-data-commons-3.0.0-M5.jar:3.0.0-M5]
		at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:184) ~[spring-aop-6.0.0-M5.jar:6.0.0-M5]
		at org.springframework.data.repository.core.support.QueryExecutorMethodInterceptor.doInvoke(QueryExecutorMethodInterceptor.java:160) ~[spring-data-commons-3.0.0-M5.jar:3.0.0-M5]
		at org.springframework.data.repository.core.support.QueryExecutorMethodInterceptor.invoke(QueryExecutorMethodInterceptor.java:135) ~[spring-data-commons-3.0.0-M5.jar:3.0.0-M5]
		at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:184) ~[spring-aop-6.0.0-M5.jar:6.0.0-M5]
		at org.springframework.data.couchbase.repository.support.CrudMethodMetadataPostProcessor$CrudMethodMetadataPopulatingMethodInterceptor.invoke(CrudMethodMetadataPostProcessor.java:173) ~[spring-data-couchbase-5.0.0-SNAPSHOT.jar:5.0.0-SNAPSHOT]
		at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:184) ~[spring-aop-6.0.0-M5.jar:6.0.0-M5]
		at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:97) ~[spring-aop-6.0.0-M5.jar:6.0.0-M5]
		at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:184) ~[spring-aop-6.0.0-M5.jar:6.0.0-M5]
		at org.springframework.data.repository.core.support.MethodInvocationValidator.invoke(MethodInvocationValidator.java:94) ~[spring-data-commons-3.0.0-M5.jar:3.0.0-M5]
		at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:184) ~[spring-aop-6.0.0-M5.jar:6.0.0-M5]
		at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:215) ~[spring-aop-6.0.0-M5.jar:6.0.0-M5]
		at jdk.proxy2/jdk.proxy2.$Proxy102.save(Unknown Source) ~[na:na]
		at com.rbleuse.spring.reactive.couchbase.service.ScheduleService.saveScheduleWithRepo(ScheduleService.kt:19) ~[main/:na]
		at com.rbleuse.spring.reactive.couchbase.service.ScheduleService$$FastClassBySpringCGLIB$$3d816b45.invoke(<generated>) ~[main/:na]
		at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:218) ~[spring-core-6.0.0-M5.jar:6.0.0-M5]
		at org.springframework.aop.framework.CglibAopProxy.invokeMethod(CglibAopProxy.java:386) ~[spring-aop-6.0.0-M5.jar:6.0.0-M5]
		at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:704) ~[spring-aop-6.0.0-M5.jar:6.0.0-M5]
		at com.rbleuse.spring.reactive.couchbase.service.ScheduleService$$EnhancerBySpringCGLIB$$1c17fc5d.saveScheduleWithRepo(<generated>) ~[main/:na]
		at com.rbleuse.spring.reactive.couchbase.handler.ScheduleHandler.createSchedule(ScheduleHandler.kt:22) ~[main/:na]
		at org.springframework.web.reactive.function.server.support.HandlerFunctionAdapter.handle(HandlerFunctionAdapter.java:61) ~[spring-webflux-6.0.0-M5.jar:6.0.0-M5]
		at org.springframework.web.reactive.DispatcherHandler.invokeHandler(DispatcherHandler.java:171) ~[spring-webflux-6.0.0-M5.jar:6.0.0-M5]
		at org.springframework.web.reactive.DispatcherHandler.lambda$handle$1(DispatcherHandler.java:153) ~[spring-webflux-6.0.0-M5.jar:6.0.0-M5]
		at reactor.core.publisher.MonoFlatMap$FlatMapMain.onNext(MonoFlatMap.java:125) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onNext(FluxSwitchIfEmpty.java:74) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.MonoNext$NextSubscriber.onNext(MonoNext.java:82) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.FluxConcatMapNoPrefetch$FluxConcatMapNoPrefetchSubscriber.innerNext(FluxConcatMapNoPrefetch.java:258) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.FluxConcatMap$ConcatMapInner.onNext(FluxConcatMap.java:863) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.FluxMapFuseable$MapFuseableSubscriber.onNext(FluxMapFuseable.java:129) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.FluxPeekFuseable$PeekFuseableSubscriber.onNext(FluxPeekFuseable.java:210) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.Operators$ScalarSubscription.request(Operators.java:2398) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.FluxPeekFuseable$PeekFuseableSubscriber.request(FluxPeekFuseable.java:144) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.FluxMapFuseable$MapFuseableSubscriber.request(FluxMapFuseable.java:171) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.Operators$MultiSubscriptionSubscriber.request(Operators.java:2158) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.FluxConcatMapNoPrefetch$FluxConcatMapNoPrefetchSubscriber.request(FluxConcatMapNoPrefetch.java:338) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.MonoNext$NextSubscriber.request(MonoNext.java:108) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.Operators$MultiSubscriptionSubscriber.set(Operators.java:2194) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.Operators$MultiSubscriptionSubscriber.onSubscribe(Operators.java:2068) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.MonoNext$NextSubscriber.onSubscribe(MonoNext.java:70) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.FluxConcatMapNoPrefetch$FluxConcatMapNoPrefetchSubscriber.onSubscribe(FluxConcatMapNoPrefetch.java:164) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.FluxIterable.subscribe(FluxIterable.java:165) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.FluxIterable.subscribe(FluxIterable.java:87) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:64) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:64) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:64) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.Mono.subscribe(Mono.java:4321) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.MonoIgnoreThen$ThenIgnoreMain.subscribeNext(MonoIgnoreThen.java:263) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.MonoIgnoreThen.subscribe(MonoIgnoreThen.java:51) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:64) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.core.publisher.MonoDeferContextual.subscribe(MonoDeferContextual.java:55) ~[reactor-core-3.5.0-M4.jar:3.5.0-M4]
		at reactor.netty.http.server.HttpServer$HttpServerHandle.onStateChange(HttpServer.java:967) ~[reactor-netty-http-1.1.0-M4.jar:1.1.0-M4]
		at reactor.netty.ReactorNetty$CompositeConnectionObserver.onStateChange(ReactorNetty.java:677) ~[reactor-netty-core-1.1.0-M4.jar:1.1.0-M4]
		at reactor.netty.transport.ServerTransport$ChildObserver.onStateChange(ServerTransport.java:478) ~[reactor-netty-core-1.1.0-M4.jar:1.1.0-M4]
		at reactor.netty.http.server.HttpServerOperations.onInboundNext(HttpServerOperations.java:570) ~[reactor-netty-http-1.1.0-M4.jar:1.1.0-M4]
		at reactor.netty.channel.ChannelOperationsHandler.channelRead(ChannelOperationsHandler.java:93) ~[reactor-netty-core-1.1.0-M4.jar:1.1.0-M4]
		at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) ~[netty-transport-4.1.79.Final.jar:4.1.79.Final]
		at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365) ~[netty-transport-4.1.79.Final.jar:4.1.79.Final]
		at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357) ~[netty-transport-4.1.79.Final.jar:4.1.79.Final]
		at reactor.netty.http.server.HttpTrafficHandler.channelRead(HttpTrafficHandler.java:222) ~[reactor-netty-http-1.1.0-M4.jar:1.1.0-M4]
		at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) ~[netty-transport-4.1.79.Final.jar:4.1.79.Final]
		at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365) ~[netty-transport-4.1.79.Final.jar:4.1.79.Final]
		at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357) ~[netty-transport-4.1.79.Final.jar:4.1.79.Final]
		at io.netty.channel.CombinedChannelDuplexHandler$DelegatingChannelHandlerContext.fireChannelRead(CombinedChannelDuplexHandler.java:436) ~[netty-transport-4.1.79.Final.jar:4.1.79.Final]
		at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:327) ~[netty-codec-4.1.79.Final.jar:4.1.79.Final]
		at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:299) ~[netty-codec-4.1.79.Final.jar:4.1.79.Final]
		at io.netty.channel.CombinedChannelDuplexHandler.channelRead(CombinedChannelDuplexHandler.java:251) ~[netty-transport-4.1.79.Final.jar:4.1.79.Final]
		at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) ~[netty-transport-4.1.79.Final.jar:4.1.79.Final]
		at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365) ~[netty-transport-4.1.79.Final.jar:4.1.79.Final]
		at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357) ~[netty-transport-4.1.79.Final.jar:4.1.79.Final]
		at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1410) ~[netty-transport-4.1.79.Final.jar:4.1.79.Final]
		at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) ~[netty-transport-4.1.79.Final.jar:4.1.79.Final]
		at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365) ~[netty-transport-4.1.79.Final.jar:4.1.79.Final]
		at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:919) ~[netty-transport-4.1.79.Final.jar:4.1.79.Final]
		at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:166) ~[netty-transport-4.1.79.Final.jar:4.1.79.Final]
		at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:722) ~[netty-transport-4.1.79.Final.jar:4.1.79.Final]
		at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:658) ~[netty-transport-4.1.79.Final.jar:4.1.79.Final]
		at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:584) ~[netty-transport-4.1.79.Final.jar:4.1.79.Final]
		at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:496) ~[netty-transport-4.1.79.Final.jar:4.1.79.Final]
		at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:997) ~[netty-common-4.1.79.Final.jar:4.1.79.Final]
		at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74) ~[netty-common-4.1.79.Final.jar:4.1.79.Final]
		at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30) ~[netty-common-4.1.79.Final.jar:4.1.79.Final]
		at java.base/java.lang.Thread.run(Thread.java:833) ~[na:na]

Should I create another issue for it ?