SpringBootTest with MockMvc and WebSocketHandlers work with Tomcat and Undertow but not with Jetty

[isopov]

Test projects may be found here: https://github.com/isopov/mockmvc-test-websocket

Basically it is simple "hello world" application with "do nothing" WebSocketHandler and MockMvc-based SpringBootTest to test "hello world" endpoint. This test passes successfully with Tomcat and Undertow in the classpath, but not with Jetty.

Full stacktrace is:

java.lang.IllegalStateException: Failed to load ApplicationContext
	at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:124) ~[spring-test-4.3.4.RELEASE.jar:4.3.4.RELEASE]
	at org.springframework.test.context.support.DefaultTestContext.getApplicationContext(DefaultTestContext.java:83) ~[spring-test-4.3.4.RELEASE.jar:4.3.4.RELEASE]
	at org.springframework.test.context.web.ServletTestExecutionListener.setUpRequestContextIfNecessary(ServletTestExecutionListener.java:189) ~[spring-test-4.3.4.RELEASE.jar:4.3.4.RELEASE]
	at org.springframework.test.context.web.ServletTestExecutionListener.prepareTestInstance(ServletTestExecutionListener.java:131) ~[spring-test-4.3.4.RELEASE.jar:4.3.4.RELEASE]
	at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:230) ~[spring-test-4.3.4.RELEASE.jar:4.3.4.RELEASE]
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.createTest(SpringJUnit4ClassRunner.java:228) [spring-test-4.3.4.RELEASE.jar:4.3.4.RELEASE]
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner$1.runReflectiveCall(SpringJUnit4ClassRunner.java:287) [spring-test-4.3.4.RELEASE.jar:4.3.4.RELEASE]
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12) [junit-4.12.jar:4.12]
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.methodBlock(SpringJUnit4ClassRunner.java:289) [spring-test-4.3.4.RELEASE.jar:4.3.4.RELEASE]
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:247) [spring-test-4.3.4.RELEASE.jar:4.3.4.RELEASE]
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:94) [spring-test-4.3.4.RELEASE.jar:4.3.4.RELEASE]
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290) [junit-4.12.jar:4.12]
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71) [junit-4.12.jar:4.12]
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288) [junit-4.12.jar:4.12]
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58) [junit-4.12.jar:4.12]
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268) [junit-4.12.jar:4.12]
	at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61) [spring-test-4.3.4.RELEASE.jar:4.3.4.RELEASE]
	at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70) [spring-test-4.3.4.RELEASE.jar:4.3.4.RELEASE]
	at org.junit.runners.ParentRunner.run(ParentRunner.java:363) [junit-4.12.jar:4.12]
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:191) [spring-test-4.3.4.RELEASE.jar:4.3.4.RELEASE]
	at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86) [.cp/:na]
	at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38) [.cp/:na]
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459) [.cp/:na]
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:675) [.cp/:na]
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382) [.cp/:na]
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192) [.cp/:na]
Caused by: org.springframework.context.ApplicationContextException: Failed to start bean 'webSocketHandlerMapping'; nested exception is java.lang.IllegalStateException: Unable to initialize Jetty WebSocketServerFactory
	at org.springframework.context.support.DefaultLifecycleProcessor.doStart(DefaultLifecycleProcessor.java:176) ~[spring-context-4.3.4.RELEASE.jar:4.3.4.RELEASE]
	at org.springframework.context.support.DefaultLifecycleProcessor.access$200(DefaultLifecycleProcessor.java:51) ~[spring-context-4.3.4.RELEASE.jar:4.3.4.RELEASE]
	at org.springframework.context.support.DefaultLifecycleProcessor$LifecycleGroup.start(DefaultLifecycleProcessor.java:346) ~[spring-context-4.3.4.RELEASE.jar:4.3.4.RELEASE]
	at org.springframework.context.support.DefaultLifecycleProcessor.startBeans(DefaultLifecycleProcessor.java:149) ~[spring-context-4.3.4.RELEASE.jar:4.3.4.RELEASE]
	at org.springframework.context.support.DefaultLifecycleProcessor.onRefresh(DefaultLifecycleProcessor.java:112) ~[spring-context-4.3.4.RELEASE.jar:4.3.4.RELEASE]
	at org.springframework.context.support.AbstractApplicationContext.finishRefresh(AbstractApplicationContext.java:879) ~[spring-context-4.3.4.RELEASE.jar:4.3.4.RELEASE]
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:545) ~[spring-context-4.3.4.RELEASE.jar:4.3.4.RELEASE]
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:761) ~[spring-boot-1.4.2.RELEASE.jar:1.4.2.RELEASE]
	at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:371) ~[spring-boot-1.4.2.RELEASE.jar:1.4.2.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:315) ~[spring-boot-1.4.2.RELEASE.jar:1.4.2.RELEASE]
	at org.springframework.boot.test.context.SpringBootContextLoader.loadContext(SpringBootContextLoader.java:111) ~[spring-boot-test-1.4.2.RELEASE.jar:1.4.2.RELEASE]
	at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContextInternal(DefaultCacheAwareContextLoaderDelegate.java:98) ~[spring-test-4.3.4.RELEASE.jar:4.3.4.RELEASE]
	at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:116) ~[spring-test-4.3.4.RELEASE.jar:4.3.4.RELEASE]
	... 25 common frames omitted
Caused by: java.lang.IllegalStateException: Unable to initialize Jetty WebSocketServerFactory
	at org.springframework.web.socket.server.jetty.JettyRequestUpgradeStrategy.start(JettyRequestUpgradeStrategy.java:164) ~[spring-websocket-4.3.4.RELEASE.jar:4.3.4.RELEASE]
	at org.springframework.web.socket.server.support.AbstractHandshakeHandler.doStart(AbstractHandshakeHandler.java:204) ~[spring-websocket-4.3.4.RELEASE.jar:4.3.4.RELEASE]
	at org.springframework.web.socket.server.support.AbstractHandshakeHandler.start(AbstractHandshakeHandler.java:198) ~[spring-websocket-4.3.4.RELEASE.jar:4.3.4.RELEASE]
	at org.springframework.web.socket.server.support.WebSocketHttpRequestHandler.start(WebSocketHttpRequestHandler.java:132) ~[spring-websocket-4.3.4.RELEASE.jar:4.3.4.RELEASE]
	at org.springframework.web.socket.server.support.WebSocketHandlerMapping.start(WebSocketHandlerMapping.java:65) ~[spring-websocket-4.3.4.RELEASE.jar:4.3.4.RELEASE]
	at org.springframework.context.support.DefaultLifecycleProcessor.doStart(DefaultLifecycleProcessor.java:173) ~[spring-context-4.3.4.RELEASE.jar:4.3.4.RELEASE]
	... 37 common frames omitted
Caused by: javax.servlet.ServletException: Not running on Jetty, WebSocket support unavailable
	at org.eclipse.jetty.websocket.server.WebSocketServerFactory.init(WebSocketServerFactory.java:393) ~[websocket-server-9.3.14.v20161028.jar:9.3.14.v20161028]
	at org.springframework.web.socket.server.jetty.JettyRequestUpgradeStrategy.start(JettyRequestUpgradeStrategy.java:160) ~[spring-websocket-4.3.4.RELEASE.jar:4.3.4.RELEASE]
	... 42 common frames omitted

[wilkinsona]

There's no standardised API for performing a WebSocket upgrade so Spring Framework has a strategy interface, RequestUpgradeStrategy, and a number of container-specific implementations. The Jetty implementation requires Jetty to be running. I don't think there's anything we can do about that in Spring Boot as it's simply due to the way that Jetty's been implemented.

@SpringBootTest indicates that you are integration testing your entire application so it would not be appropriate for Spring Boot to ignore @EnableWebSocket. You could use @SpringBootTest with webEnvironment=RANDOM_PORT and use TestRestTemplate rather than MockMvc. If you want to continue using MockMvc, then I think you'd probably be better restructuring things a little so that @EnableWebSocket only comes into effect when you're running your app or a full-blown integration test that actually starts the embedded container.

One final point to note is that this test will reproduce the problem without any involvement from Spring Boot:

public class MockServletContextJettyWebSocketTests {

    @Test
    public void test() {
        AnnotationConfigWebApplicationContext context = new AnnotationConfigWebApplicationContext();
        context.setServletContext(new MockServletContext());
        context.register(ExampleConfiguration.class);
        context.refresh();
    }

    @Configuration
    @EnableWebSocket
    static class ExampleConfiguration implements WebSocketConfigurer {

        @Override
        public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
            registry.addHandler(webSocketHandler(), "/ws");
        }

        @Bean
        public WebSocketHandler webSocketHandler() {
            return new TextWebSocketHandler();
        }

    }
    
}

If you'd like to pursue your current arrangement working with Jetty then please open a Spring Framework JIRA ticket.

[jmc420]

I have been struggling to get integration tests working with jetty and websockets and came across this issue.

I checked out https://github.com/isopov/mockmvc-test-websocket and it does not work with jetty.

It seems to be related to https://jira.spring.io/browse/SPR-16263

Within the init method of WebSocketServerFactory, this exception is thrown

ContextHandler handler = ContextHandler.getContextHandler(context);

if (handler == null)
{
throw new ServletException("Not running on Jetty, WebSocket support unavailable");
}

According to the jira, it appears this is because Spring's MockServletContext doesn't implement Jetty's ContextHandler.Context; i.e. ContextHandler.getContextHandler(context); returns null.

is there anyway to get websocket integration tests (with or without spring boot) to work jetty?

[wilkinsona]

Is there anyway to get websocket integration tests (with or without spring boot) to work jetty?

Yes, I believe you can integration test WebSockets with Jetty by starting Jetty rather than trying to use MockMvc. If you need some help with that, please ask on Stack Overflow or Gitter. As mentioned in the guidelines for contributing, we prefer to use GitHub issues only for bugs and enhancements.

[jmc420]

I have posted a question here:

https://stackoverflow.com/questions/49446510/spring-integration-testing-with-jetty-and-websockets

[joakime]

@jmc420 start a real jetty server for your websocket testing. It starts faster then the Spring MockMVC anyway. (in our testing we can start a real server, toss a dozen messages with echo at the websocket, and shutdown the server in under 150ms)

As for ...

ContextHandler handler = ContextHandler.getContextHandler(context);

if (handler == null)
{
throw new ServletException("Not running on Jetty, WebSocket support unavailable");
}

That's from the WebSocketUpgradeFilter (Not the WebSocketServerFactory).

In WebSocket on Jetty there are 2 such checks ...

org/eclipse/jetty/websocket/server/WebSocketUpgradeFilter.java

org/eclipse/jetty/websocket/jsr356/server/deploy/WebSocketServerContainerInitializer.java

The internal use of the Jetty ContextHandler and ServletContextHandler exist to manage the Jetty object LifeCycle and allow reuse of other expensive LifeCycle components (such as the ThreadPool, Executor, and HttpClient)

I'd be open to making Jetty (perhaps Jetty 9.4.10, definitely Jetty 10.x) a bit more flexible here to allow MockMVC.

What's the requirements from the MockMVC point of view?

[jmc420]

@joakime Thanks for the reply.

I would see if you can get it working with the (unit) test in the example repo above:

https://github.com/isopov/mockmvc-test-websocket/blob/master/mockmvc-test-websocket-jetty/src/test/java/com/example/MockmvcTestWebsocketJettyApplicationTests.java

As I mentioned in the stackoverflow post, I am running a Jetty integration (rather than unit) test using these annotations:

@RunWith( SpringJUnit4ClassRunner.class )
@ContextConfiguration( classes = { ApplicationConfig.class } )
@WebAppConfiguration

When I run this without a WebSocket configuration picked up by component scanning, everything works fine, but when I introduce a WebSocket configuration it fails because of which is the exception (throw new ServletException("Not running on Jetty, WebSocket support unavailable");)

I am running Jetty 9.3 which is why it appears for me in WebSocketServerFactory rather than WebSocketUpgradeFilter.

[joakime]

Looking at this ...

Why does JettyRequestUpgradeStrategy exist this way?
Why is the ServletContext arriving late? and via a .setServletContext call, and not as part of the constructor?
Using Jetty's WebSocketHandler as your example to base JettyRequestUpgradeStrategy against is super strange.
Of the various ways to implement a websocket server on Jetty, someone chose to use the one and only way that doesn't have/use a standard javax.servlet.ServletContext to begin with.
Does this MockMVC layer perform any javax.servlet.ServletContainerInitializer behaviors? (doesn't appear to)

Hmm, lots of strange decisions here.
I'll have to work out why first, then see if I can replace all of this with just a simple SCI usage. (it would be backward compatible to Jetty 9.0 too!)

[wilkinsona]

Those are interesting questions, but they're question for the Spring Framework team. The code in question is not part of Spring Boot.

/cc @rstoyanchev

[joakime]

I've made some minor changes to WebSocketServerFactory to allow MockMVC to function.

Jetty Branch: https://github.com/eclipse/jetty.project/tree/jetty-9.4.x-issue-2376-ws-context-relaxation
Mockmvc-test-websocket fork: https://github.com/joakime/mockmvc-test-websocket

Let me know if this is sufficient (for now), or of anything else is needed?

Aside: I think the Jetty implementation for upgrade at Spring Framework needs an overhaul to be more resilient.
Using the WebSocketServerFactory directly like it's doing is probably the most complex approach that could have been taken.