SpringEventTranslator - do not relay events if the reactor Environment is not alive

[zyro23]

Task List

• Steps to reproduce provided
• Stacktrace (if present) provided
• Example that reproduces the problem uploaded to Github
• Full description of the issue provided (see below)

Steps to Reproduce

1. run sample-app
2. see stacktrace

Expected Behaviour

• the application should shutdown gracefully without errors
• SpringEventTranslator should only relay events to reactor if the reactor Environment is alive
  • which is not always the case during application shutdown / spring context closing

i tried to override springReactorEventTranslator with a custom impl like this:

void onApplicationEvent(ApplicationEvent event) {
    def eventName = eventClassToName[event.getClass()]
    // don't relay events if Reactor is shutdown
    if (Environment.alive()) {
        notify(eventName, eventFor(event))
    }
}

this brought the desired result (clean shutdown)

Actual Behaviour

• the spring websocket support fires a BrokerAvailabilityEvent (false) when the ApplicationContext is closed
• that results in an exception (reactor dispatcher already closed)

stacktrace:

java.lang.IllegalArgumentException: This Dispatcher has been shut down.
    at reactor.core.support.Assert.isTrue(Assert.java:61) ~[reactor-core-2.0.7.RELEASE.jar:na]
    at reactor.core.dispatch.AbstractLifecycleDispatcher.dispatch(AbstractLifecycleDispatcher.java:111) ~[reactor-core-2.0.7.RELEASE.jar:na]
    at reactor.bus.EventBus.notify(EventBus.java:368) ~[reactor-bus-2.0.7.RELEASE.jar:na]
    at grails.events.Events$Trait$Helper.notify(Events.groovy:111) ~[grails-plugin-events-3.1.6.jar:3.1.6]
    at org.grails.events.spring.SpringEventTranslator.notify(SpringEventTranslator.groovy) ~[grails-plugin-events-3.1.6.jar:3.1.6]
    at org.grails.events.spring.SpringEventTranslator.onApplicationEvent(SpringEventTranslator.groovy:63) ~[grails-plugin-events-3.1.6.jar:3.1.6]
    at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:163) ~[spring-context-4.2.5.RELEASE.jar:4.2.5.RELEASE]
    at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:136) ~[spring-context-4.2.5.RELEASE.jar:4.2.5.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:381) [spring-context-4.2.5.RELEASE.jar:4.2.5.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:335) [spring-context-4.2.5.RELEASE.jar:4.2.5.RELEASE]
    at org.springframework.messaging.simp.broker.AbstractBrokerMessageHandler.publishBrokerUnavailableEvent(AbstractBrokerMessageHandler.java:272) ~[spring-messaging-4.2.5.RELEASE.jar:4.2.5.RELEASE]
    at org.springframework.messaging.simp.broker.SimpleBrokerMessageHandler.stopInternal(SimpleBrokerMessageHandler.java:206) ~[spring-messaging-4.2.5.RELEASE.jar:4.2.5.RELEASE]
    at org.springframework.messaging.simp.broker.AbstractBrokerMessageHandler.stop(AbstractBrokerMessageHandler.java:179) ~[spring-messaging-4.2.5.RELEASE.jar:4.2.5.RELEASE]
    at org.springframework.messaging.simp.broker.AbstractBrokerMessageHandler.stop(AbstractBrokerMessageHandler.java:196) ~[spring-messaging-4.2.5.RELEASE.jar:4.2.5.RELEASE]
    at org.springframework.context.support.DefaultLifecycleProcessor.doStop(DefaultLifecycleProcessor.java:229) [spring-context-4.2.5.RELEASE.jar:4.2.5.RELEASE]
    at org.springframework.context.support.DefaultLifecycleProcessor.access$300(DefaultLifecycleProcessor.java:51) [spring-context-4.2.5.RELEASE.jar:4.2.5.RELEASE]
    at org.springframework.context.support.DefaultLifecycleProcessor$LifecycleGroup.stop(DefaultLifecycleProcessor.java:363) [spring-context-4.2.5.RELEASE.jar:4.2.5.RELEASE]
    at org.springframework.context.support.DefaultLifecycleProcessor.stopBeans(DefaultLifecycleProcessor.java:202) [spring-context-4.2.5.RELEASE.jar:4.2.5.RELEASE]
    at org.springframework.context.support.DefaultLifecycleProcessor.onClose(DefaultLifecycleProcessor.java:118) [spring-context-4.2.5.RELEASE.jar:4.2.5.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.doClose(AbstractApplicationContext.java:975) [spring-context-4.2.5.RELEASE.jar:4.2.5.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext$1.run(AbstractApplicationContext.java:901) [spring-context-4.2.5.RELEASE.jar:4.2.5.RELEASE]

2016-05-05 13:27:54.829  WARN 4976 --- [       Thread-9] o.s.c.support.DefaultLifecycleProcessor  : Failed to shut down 1 bean with phase value 2147483647 within timeout of 30000: [simpleBrokerMessageHandler]

Environment Information

• Operating System: win x64
• Grails Version: 3.1.6
• JDK Version: 8
• Container Version (If Applicable): n/a

Example Application

• see referenced commit
• added grails-spring-websocket plugin, no further config
• the Application class does a Runtime.runtime.exit 0 right after the app started

[ZacharyKlein]

I'm seeing this behavior on 3.1.8.