java spring spring-boot spring-cloud spring-webflux
Spring Cloud Hoxton.SR5 issue with Eureka and WebFlux: Exceeded limit on max bytes to buffer

We have Spring Cloud application using Eureka as service discovery, Config Service and WebFlux. Service works fine with Spring Cloud Hoxton.SR4, but fails with Hoxton.SR5 on app start during fetching data from Eureka. If Eureka has small number of registered apps (e.g. 30), it works fine, but in case it has around 250 services, it fails with the following exception
DataBufferLimitException: Exceeded limit on max bytes to buffer : 262144 Error has been observed at the following site(s): checkpoint ⇢ Body from GET http://eureka.xxx.com:8080/eureka/apps/?regions=us-east-1.
If we remove WebFlux from classpath, it also works fine even with Hoxton.SR5. I provided reproducible issue on github (but in order to reproduce, we need to connect to Eureka having several hundreds of registered apps). I also saw issue with similar exception , in their case issue occurred on the controller side, but in our case on app start, and property spring.codec.max-in-memory-size doesn't work here.
Spring Boot version 2.3.1.RELEASE.
Stack trace:
org.springframework.core.io.buffer.DataBufferLimitException: Exceeded limit on max bytes to buffer : 262144
    at org.springframework.core.io.buffer.LimitedDataBufferList.raiseLimitException(LimitedDataBufferList.java:101) ~[spring-core-5.2.7.RELEASE.jar:5.2.7.RELEASE]
    Suppressed: reactor.core.publisher.FluxOnAssembly$OnAssemblyException: 
Error has been observed at the following site(s):
    |_ checkpoint ⇢ Body from GET http://eureka.xxx.com:8080/eureka/apps/?regions=us-east-1 [DefaultClientResponse]
Stack trace:
        at org.springframework.core.io.buffer.LimitedDataBufferList.raiseLimitException(LimitedDataBufferList.java:101) ~[spring-core-5.2.7.RELEASE.jar:5.2.7.RELEASE]
        at org.springframework.core.io.buffer.LimitedDataBufferList.updateCount(LimitedDataBufferList.java:94) ~[spring-core-5.2.7.RELEASE.jar:5.2.7.RELEASE]
        at org.springframework.core.io.buffer.LimitedDataBufferList.add(LimitedDataBufferList.java:59) ~[spring-core-5.2.7.RELEASE.jar:5.2.7.RELEASE]
        at reactor.core.publisher.MonoCollect$CollectSubscriber.onNext(MonoCollect.java:124) ~[reactor-core-3.3.6.RELEASE.jar:3.3.6.RELEASE]
        at reactor.core.publisher.FluxMap$MapSubscriber.onNext(FluxMap.java:114) ~[reactor-core-3.3.6.RELEASE.jar:3.3.6.RELEASE]
        at reactor.core.publisher.FluxPeek$PeekSubscriber.onNext(FluxPeek.java:192) ~[reactor-core-3.3.6.RELEASE.jar:3.3.6.RELEASE]
        at reactor.core.publisher.FluxPeek$PeekSubscriber.onNext(FluxPeek.java:192) ~[reactor-core-3.3.6.RELEASE.jar:3.3.6.RELEASE]
        at reactor.core.publisher.FluxMap$MapSubscriber.onNext(FluxMap.java:114) ~[reactor-core-3.3.6.RELEASE.jar:3.3.6.RELEASE]
        at reactor.netty.channel.FluxReceive.onInboundNext(FluxReceive.java:330) ~[reactor-netty-0.9.8.RELEASE.jar:0.9.8.RELEASE]
        at reactor.netty.channel.ChannelOperations.onInboundNext(ChannelOperations.java:353) ~[reactor-netty-0.9.8.RELEASE.jar:0.9.8.RELEASE]
        at reactor.netty.http.client.HttpClientOperations.onInboundNext(HttpClientOperations.java:635) ~[reactor-netty-0.9.8.RELEASE.jar:0.9.8.RELEASE]
        at reactor.netty.channel.ChannelOperationsHandler.channelRead(ChannelOperationsHandler.java:96) ~[reactor-netty-0.9.8.RELEASE.jar:0.9.8.RELEASE]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) ~[netty-transport-4.1.50.Final.jar:4.1.50.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365) ~[netty-transport-4.1.50.Final.jar:4.1.50.Final]
        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357) ~[netty-transport-4.1.50.Final.jar:4.1.50.Final]
        at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103) ~[netty-codec-4.1.50.Final.jar:4.1.50.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) ~[netty-transport-4.1.50.Final.jar:4.1.50.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365) ~[netty-transport-4.1.50.Final.jar:4.1.50.Final]
        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357) ~[netty-transport-4.1.50.Final.jar:4.1.50.Final]
        at io.netty.channel.CombinedChannelDuplexHandler$DelegatingChannelHandlerContext.fireChannelRead(CombinedChannelDuplexHandler.java:436) ~[netty-transport-4.1.50.Final.jar:4.1.50.Final]
        at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:324) ~[netty-codec-4.1.50.Final.jar:4.1.50.Final]
        at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:311) ~[netty-codec-4.1.50.Final.jar:4.1.50.Final]
        at io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:425) ~[netty-codec-4.1.50.Final.jar:4.1.50.Final]
        at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:276) ~[netty-codec-4.1.50.Final.jar:4.1.50.Final]
        at io.netty.channel.CombinedChannelDuplexHandler.channelRead(CombinedChannelDuplexHandler.java:251) ~[netty-transport-4.1.50.Final.jar:4.1.50.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) ~[netty-transport-4.1.50.Final.jar:4.1.50.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365) ~[netty-transport-4.1.50.Final.jar:4.1.50.Final]
        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357) ~[netty-transport-4.1.50.Final.jar:4.1.50.Final]
        at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1410) ~[netty-transport-4.1.50.Final.jar:4.1.50.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) ~[netty-transport-4.1.50.Final.jar:4.1.50.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365) ~[netty-transport-4.1.50.Final.jar:4.1.50.Final]
        at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:919) ~[netty-transport-4.1.50.Final.jar:4.1.50.Final]
        at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:163) ~[netty-transport-4.1.50.Final.jar:4.1.50.Final]
        at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:714) ~[netty-transport-4.1.50.Final.jar:4.1.50.Final]
        at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:650) ~[netty-transport-4.1.50.Final.jar:4.1.50.Final]
        at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:576) ~[netty-transport-4.1.50.Final.jar:4.1.50.Final]
        at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:493) ~[netty-transport-4.1.50.Final.jar:4.1.50.Final]
        at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989) ~[netty-common-4.1.50.Final.jar:4.1.50.Final]
        at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74) ~[netty-common-4.1.50.Final.jar:4.1.50.Final]
        at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30) ~[netty-common-4.1.50.Final.jar:4.1.50.Final]
        at java.base/java.lang.Thread.run(Thread.java:835) ~[na:na]
    Suppressed: java.lang.Exception: #block terminated with an error
        at reactor.core.publisher.BlockingSingleSubscriber.blockingGet(BlockingSingleSubscriber.java:99) ~[reactor-core-3.3.6.RELEASE.jar:3.3.6.RELEASE]
        at reactor.core.publisher.Mono.block(Mono.java:1679) ~[reactor-core-3.3.6.RELEASE.jar:3.3.6.RELEASE]
        at org.springframework.cloud.netflix.eureka.http.WebClientEurekaHttpClient.getApplicationsInternal(WebClientEurekaHttpClient.java:143) ~[spring-cloud-netflix-eureka-client-2.2.3.RELEASE.jar:2.2.3.RELEASE]
        at org.springframework.cloud.netflix.eureka.http.WebClientEurekaHttpClient.getApplications(WebClientEurekaHttpClient.java:124) ~[spring-cloud-netflix-eureka-client-2.2.3.RELEASE.jar:2.2.3.RELEASE]
        at org.springframework.cloud.netflix.eureka.config.EurekaConfigServerBootstrapConfiguration.lambda$eurekaConfigServerInstanceProvider$0(EurekaConfigServerBootstrapConfiguration.java:112) ~[spring-cloud-netflix-eureka-client-2.2.3.RELEASE.jar:2.2.3.RELEASE]
        at org.springframework.cloud.config.client.ConfigServerInstanceProvider.getConfigServerInstances(ConfigServerInstanceProvider.java:50) ~[spring-cloud-config-client-2.2.3.RELEASE.jar:2.2.3.RELEASE]
        at org.springframework.cloud.config.client.DiscoveryClientConfigServiceBootstrapConfiguration$HeartbeatListener.refresh(DiscoveryClientConfigServiceBootstrapConfiguration.java:120) ~[spring-cloud-config-client-2.2.3.RELEASE.jar:2.2.3.RELEASE]
        at org.springframework.cloud.config.client.DiscoveryClientConfigServiceBootstrapConfiguration$HeartbeatListener.startup(DiscoveryClientConfigServiceBootstrapConfiguration.java:106) ~[spring-cloud-config-client-2.2.3.RELEASE.jar:2.2.3.RELEASE]
        at org.springframework.cloud.config.client.DiscoveryClientConfigServiceBootstrapConfiguration$HeartbeatListener.onApplicationEvent(DiscoveryClientConfigServiceBootstrapConfiguration.java:98) ~[spring-cloud-config-client-2.2.3.RELEASE.jar:2.2.3.RELEASE]
        at org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener(SimpleApplicationEventMulticaster.java:172) ~[spring-context-5.2.7.RELEASE.jar:5.2.7.RELEASE]
        at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:165) ~[spring-context-5.2.7.RELEASE.jar:5.2.7.RELEASE]
        at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:139) ~[spring-context-5.2.7.RELEASE.jar:5.2.7.RELEASE]
        at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:404) ~[spring-context-5.2.7.RELEASE.jar:5.2.7.RELEASE]
        at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:361) ~[spring-context-5.2.7.RELEASE.jar:5.2.7.RELEASE]
        at org.springframework.context.support.AbstractApplicationContext.finishRefresh(AbstractApplicationContext.java:898) ~[spring-context-5.2.7.RELEASE.jar:5.2.7.RELEASE]
        at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:554) ~[spring-context-5.2.7.RELEASE.jar:5.2.7.RELEASE]
        at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:758) ~[spring-boot-2.3.1.RELEASE.jar:2.3.1.RELEASE]
        at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:750) ~[spring-boot-2.3.1.RELEASE.jar:2.3.1.RELEASE]
        at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397) ~[spring-boot-2.3.1.RELEASE.jar:2.3.1.RELEASE]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:315) ~[spring-boot-2.3.1.RELEASE.jar:2.3.1.RELEASE]
        at org.springframework.boot.builder.SpringApplicationBuilder.run(SpringApplicationBuilder.java:140) ~[spring-boot-2.3.1.RELEASE.jar:2.3.1.RELEASE]
        at org.springframework.cloud.bootstrap.BootstrapApplicationListener.bootstrapServiceContext(BootstrapApplicationListener.java:212) ~[spring-cloud-context-2.2.3.RELEASE.jar:2.2.3.RELEASE]
        at org.springframework.cloud.bootstrap.BootstrapApplicationListener.onApplicationEvent(BootstrapApplicationListener.java:117) ~[spring-cloud-context-2.2.3.RELEASE.jar:2.2.3.RELEASE]
        at org.springframework.cloud.bootstrap.BootstrapApplicationListener.onApplicationEvent(BootstrapApplicationListener.java:74) ~[spring-cloud-context-2.2.3.RELEASE.jar:2.2.3.RELEASE]
        at org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener(SimpleApplicationEventMulticaster.java:172) ~[spring-context-5.2.7.RELEASE.jar:5.2.7.RELEASE]
        at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:165) ~[spring-context-5.2.7.RELEASE.jar:5.2.7.RELEASE]
        at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:139) ~[spring-context-5.2.7.RELEASE.jar:5.2.7.RELEASE]
        at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:127) ~[spring-context-5.2.7.RELEASE.jar:5.2.7.RELEASE]
        at org.springframework.boot.context.event.EventPublishingRunListener.environmentPrepared(EventPublishingRunListener.java:80) ~[spring-boot-2.3.1.RELEASE.jar:2.3.1.RELEASE]
        at org.springframework.boot.SpringApplicationRunListeners.environmentPrepared(SpringApplicationRunListeners.java:53) ~[spring-boot-2.3.1.RELEASE.jar:2.3.1.RELEASE]
        at org.springframework.boot.SpringApplication.prepareEnvironment(SpringApplication.java:345) ~[spring-boot-2.3.1.RELEASE.jar:2.3.1.RELEASE]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:308) ~[spring-boot-2.3.1.RELEASE.jar:2.3.1.RELEASE]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:1237) ~[spring-boot-2.3.1.RELEASE.jar:2.3.1.RELEASE]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:1226) ~[spring-boot-2.3.1.RELEASE.jar:2.3.1.RELEASE]
        at com.vsarzhynskyi.springcloud.hoxtonsr5.ReproducibleIssueApplication.main(ReproducibleIssueApplication.java:10) ~[classes/:na]
Solution
it was a bug Spring Cloud Hoxton.SR5 issue with Eureka and WebFlux: Exceeded limit on max bytes to buffer #3819. issue is fixed with Spring Cloud version Hoxton.SR7.