问题描述
根据 Spring Cloud Stream Binder Kafka 发送消息/接收消息的代码示例，只需要配置好 application.yaml 中的 event hub connection string, Event Hub Name就可以正常运行并查看执行结果。
但是，当使用JMeter作并发测试时候，就会遇见异常, 主要的异常信息为：reactor.core.publisher.Sinks$EmissionException: Spec. Rule 1.3 - onSubscribe, onNext, onError and onComplete signaled to a Subscriber MUST be signaled serially. 这是Sinks中发送者发送消息的时候，调用 onSubscribe、onNext、onError 和 onComplete 必须顺序执行，不能并发操作。
完整的异常日志：
2025-02-18T13:08:34.399+08:00 ERROR 35416 --- [io-8080-exec-41] o.a.c.c.C.[.[.[/].[dispatcherServlet] : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed: reactor.core.publisher.Sinks$EmissionException: Spec. Rule 1.3 - onSubscribe, onNext, onError and onComplete signaled to a Subscriber MUST be signaled serially.] with root cause reactor.core.publisher.Sinks$EmissionException: Spec. Rule 1.3 - onSubscribe, onNext, onError and onComplete signaled to a Subscriber MUST be signaled serially. at reactor.core.publisher.InternalManySink.emitNext(InternalManySink.java:56) ~[reactor-core-3.7.2.jar:3.7.2] at com.azure.spring.sample.eventhubs.SourceExample.sendMessage(SourceExample.java:22) ~[classes/:na] at jdk.internal.reflect.GeneratedMethodAccessor5.invoke(Unknown Source) ~[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.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:257) ~[spring-web-6.2.2.jar:6.2.2] at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:190) ~[spring-web-6.2.2.jar:6.2.2] at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:118) ~[spring-webmvc-6.2.2.jar:6.2.2] at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:986) ~[spring-webmvc-6.2.2.jar:6.2.2] at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:891) ~[spring-webmvc-6.2.2.jar:6.2.2] at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-6.2.2.jar:6.2.2] at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1088) ~[spring-webmvc-6.2.2.jar:6.2.2] at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:978) ~[spring-webmvc-6.2.2.jar:6.2.2] at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1014) ~[spring-webmvc-6.2.2.jar:6.2.2] at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:914) ~[spring-webmvc-6.2.2.jar:6.2.2] at jakarta.servlet.http.HttpServlet.service(HttpServlet.java:590) ~[tomcat-embed-core-10.1.34.jar:6.0] at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:885) ~[spring-webmvc-6.2.2.jar:6.2.2] at jakarta.servlet.http.HttpServlet.service(HttpServlet.java:658) ~[tomcat-embed-core-10.1.34.jar:6.0] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:195) ~[tomcat-embed-core-10.1.34.jar:10.1.34] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:140) ~[tomcat-embed-core-10.1.34.jar:10.1.34] at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51) ~[tomcat-embed-websocket-10.1.34.jar:10.1.34] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:164) ~[tomcat-embed-core-10.1.34.jar:10.1.34] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:140) ~[tomcat-embed-core-10.1.34.jar:10.1.34] at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-6.2.2.jar:6.2.2] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116) ~[spring-web-6.2.2.jar:6.2.2] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:164) ~[tomcat-embed-core-10.1.34.jar:10.1.34] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:140) ~[tomcat-embed-core-10.1.34.jar:10.1.34] at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-6.2.2.jar:6.2.2] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116) ~[spring-web-6.2.2.jar:6.2.2] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:164) ~[tomcat-embed-core-10.1.34.jar:10.1.34] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:140) ~[tomcat-embed-core-10.1.34.jar:10.1.34] at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-6.2.2.jar:6.2.2] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116) ~[spring-web-6.2.2.jar:6.2.2] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:164) ~[tomcat-embed-core-10.1.34.jar:10.1.34] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:140) ~[tomcat-embed-core-10.1.34.jar:10.1.34] at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:167) ~[tomcat-embed-core-10.1.34.jar:10.1.34] at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:90) ~[tomcat-embed-core-10.1.34.jar:10.1.34] at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:483) ~[tomcat-embed-core-10.1.34.jar:10.1.34] at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:115) ~[tomcat-embed-core-10.1.34.jar:10.1.34] at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:93) ~[tomcat-embed-core-10.1.34.jar:10.1.34] at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) ~[tomcat-embed-core-10.1.34.jar:10.1.34] at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:344) ~[tomcat-embed-core-10.1.34.jar:10.1.34] at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:397) ~[tomcat-embed-core-10.1.34.jar:10.1.34] at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:63) ~[tomcat-embed-core-10.1.34.jar:10.1.34] at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:905) ~[tomcat-embed-core-10.1.34.jar:10.1.34] at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1741) ~[tomcat-embed-core-10.1.34.jar:10.1.34] at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:52) ~[tomcat-embed-core-10.1.34.jar:10.1.34] at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1190) ~[tomcat-embed-core-10.1.34.jar:10.1.34] at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659) ~[tomcat-embed-core-10.1.34.jar:10.1.34] at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:63) ~[tomcat-embed-core-10.1.34.jar:10.1.34] at java.base/java.lang.Thread.run(Thread.java:833) ~[na:na]
问题解答
错误的原因主要是在发送消息的方法中使用了 Sinks.EmitFailureHandler.FAIL_FAST参数，这个参数表示只要发送消息失败，不进行任何重试，直接返回异常。
在Sinks类中，因无法使用 EmitResult 中的其它参数来代替EmitFailureHandler.FAIL_FAST， 所以只能使用 tryEmitNext 方法来缓解此问题。
参考资料
Sending and Receiving Message by Azure Event Hubs and Spring Cloud Stream Binder Kafka in Spring Boot Application : https://github.com/Azure-Samples/azure-spring-boot-samples/tree/main/eventhubs/spring-cloud-azure-starter/spring-cloud-azure-sample-eventhubs-kafka
【Azure 事件中心】Spring Cloud Stream Event Hubs Binder 发送Event Hub消息遇见 Spec. Rule 1.3 - onSubscribe, onNext, onError and onComplete signaled to a Subscriber MUST be signaled serially 异常 ：https://www.cnblogs.com/lulight/p/17357267.html
