Undertow Websockets: Could not create an endpoint dynamically

[pjgg]

Describe the bug

Extensions: io.quarkus:quarkus-undertow-websockets

On version 1.11.7.Final I could create an endpoint dynamically as follow:

 ((ServerContainer) sce.getServletContext().getAttribute(ServerContainer.class.getName()))
                    .addEndpoint(ServerEndpointConfig.Builder.create(WebsockEndpoint.class, "/simple")
                            .configurator(new WebsockEndpointConfigurator(this)).build());

However after upgrade to version 1.13.7.Final I got a NullPointerException

Caused by: java.lang.RuntimeException: java.lang.RuntimeException: java.lang.NullPointerException
	at io.quarkus.undertow.runtime.UndertowDeploymentRecorder.bootServletContainer(UndertowDeploymentRecorder.java:528)
	at io.quarkus.deployment.steps.UndertowBuildStep$build-649634386.deploy_0(UndertowBuildStep$build-649634386.zig:238)
	at io.quarkus.deployment.steps.UndertowBuildStep$build-649634386.deploy(UndertowBuildStep$build-649634386.zig:40)
	at io.quarkus.runner.ApplicationImpl.<clinit>(ApplicationImpl.zig:169)
	... 43 more
Caused by: java.lang.RuntimeException: java.lang.NullPointerException
	at io.undertow.servlet.core.DeploymentManagerImpl.deploy(DeploymentManagerImpl.java:253)
	at io.quarkus.undertow.runtime.UndertowDeploymentRecorder.bootServletContainer(UndertowDeploymentRecorder.java:517)
	... 46 more
Caused by: java.lang.NullPointerException
	at io.quarkus.qe.undertow.PongLeakSample.contextInitialized(PongLeakSample.java:51)

Here I paste you a full reproducer:

import java.io.IOException;
import java.util.Collections;
import java.util.IdentityHashMap;
import java.util.Set;

import javax.enterprise.inject.spi.DeploymentException;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.servlet.annotation.WebListener;
import javax.websocket.CloseReason;
import javax.websocket.Endpoint;
import javax.websocket.EndpointConfig;
import javax.websocket.Session;
import javax.websocket.server.ServerContainer;
import javax.websocket.server.ServerEndpointConfig;

import org.jboss.logging.Logger;

@WebListener
public class PongLeakSample implements ServletContextListener {
    private static final Logger LOG = Logger.getLogger(PongLeakSample.class);

    private Thread pingThread;
    private Set<WebsockEndpoint> endpoints;

    public PongLeakSample() {
        endpoints = Collections.synchronizedSet(Collections.newSetFromMap(new IdentityHashMap<>()));
    }

    @Override
    public void contextDestroyed(ServletContextEvent sce) {
        pingThread.interrupt();
        endpoints.forEach(WebsockEndpoint::close);
        try {
            pingThread.join();
        } catch (InterruptedException e) {
            Thread.currentThread().interrupt();
        }
    }

    /**
     * @see ServletContextListener#contextInitialized(ServletContextEvent)
     */
    @Override
    public void contextInitialized(ServletContextEvent sce) {
        try {
            ((ServerContainer) sce.getServletContext().getAttribute(ServerContainer.class.getName()))
                    .addEndpoint(ServerEndpointConfig.Builder.create(WebsockEndpoint.class, "/simple")
                            .configurator(new WebsockEndpointConfigurator(this)).build());
            
        } catch (DeploymentException | javax.websocket.DeploymentException e) {
            e.printStackTrace();
        }
        pingThread = new Thread(this::pingRoutine);
        pingThread.setDaemon(true);
        pingThread.start();
    }

    private void pingRoutine() {
        try {
            while (true) {
                Thread.sleep(300);
                endpoints.forEach(WebsockEndpoint::ping);
            }
        } catch (InterruptedException e) {
            Thread.currentThread().interrupt();
        }
    }

    public static class WebsockEndpoint extends Endpoint {

        private static final String PONG = "PONG";
        private final PongLeakSample filter;
        private Session session;

        public WebsockEndpoint(PongLeakSample filter) {
            this.filter = filter;
        }

        @Override
        public void onOpen(Session session, EndpointConfig config) {
            this.session = session;
            filter.endpoints.add(this);
        }

        @Override
        public void onClose(Session session, CloseReason closeReason) {
            filter.endpoints.remove(this);
        }

        public void ping() {
            LOG.info("ping-pong invoked!");
            session.getAsyncRemote().sendText(PONG);
        }

        public void close() {
            try {
                session.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    public static class WebsockEndpointConfigurator extends ServerEndpointConfig.Configurator {
        private PongLeakSample filter;

        WebsockEndpointConfigurator(PongLeakSample filter) {
            this.filter = filter;
        }

        @Override
        public <T> T getEndpointInstance(Class<T> endpointClass) throws InstantiationException {
            WebsockEndpoint endpoint = new WebsockEndpoint(filter);
            if (endpointClass.isInstance(endpoint))
                return endpointClass.cast(endpoint);
            throw new InstantiationException(
                    "Requested class is not assignable from " + WebsockEndpoint.class.getName());
        }
    }
}

Run: mvn quarkus:dev

Test: curl --include \\n --no-buffer \\n --header "Connection: Upgrade" \\n --header "Upgrade: websocket" \\n --header "Sec-WebSocket-Key: SGVsbG8sIHdvcmxkIQ==" \\n --header "Sec-WebSocket-Version: 13" \\n http://localhost:8080/simple

Works on: 1.11.7.Final

Fails on: 1.13.7.Final (and higher)

[gastaldi]

/cc @stuartwdouglas

[gastaldi]

FYI you can also fetch an instance of the configured ServerContainer by doing:

ServerContainer container = (ServerContainer) ContainerProvider.getWebSocketContainer();

But then you get an error when you try to deploy:

Caused by: java.lang.RuntimeException: java.lang.IllegalStateException: UT003017: Cannot add endpoint after deployment
	at io.undertow.servlet.core.DeploymentManagerImpl.deploy(DeploymentManagerImpl.java:253)
	at io.quarkus.undertow.runtime.UndertowDeploymentRecorder.bootServletContainer(UndertowDeploymentRecorder.java:510)

[pjgg]

So do you think that is still possible to create an endpoint programmatically(dynamically), on Quarkus 1.13.7 or higher?

2021-09-01 09:18:24,874 INFO  [io.und.web.jsr] (main) UT026005: Adding programmatic server endpoint class io.quarkus.qe.undertow.PongLeakSample$WebsockEndpoint for path /simple

[rsvoboda]

@gastaldi / @stuartwdouglas