5 files changed, 79 insertions, 49 deletions

diff --git a/subprojects/language-web/src/main/java/tools/refinery/language/web/ProblemWebModule.java b/subprojects/language-web/src/main/java/tools/refinery/language/web/ProblemWebModule.java
index ec55036f..706413a9 100644
--- a/subprojects/language-web/src/main/java/tools/refinery/language/web/ProblemWebModule.java
+++ b/subprojects/language-web/src/main/java/tools/refinery/language/web/ProblemWebModule.java
@@ -3,12 +3,13 @@
  */
 package tools.refinery.language.web;
 
+import org.eclipse.xtext.ide.ExecutorServiceProvider;
 import org.eclipse.xtext.web.server.XtextServiceDispatcher;
 import org.eclipse.xtext.web.server.model.IWebDocumentProvider;
 import org.eclipse.xtext.web.server.model.XtextWebDocumentAccess;
 import org.eclipse.xtext.web.server.occurrences.OccurrencesService;
-
 import tools.refinery.language.web.occurrences.ProblemOccurrencesService;
+import tools.refinery.language.web.xtext.VirtualThreadExecutorServiceProvider;
 import tools.refinery.language.web.xtext.server.push.PushServiceDispatcher;
 import tools.refinery.language.web.xtext.server.push.PushWebDocumentAccess;
 import tools.refinery.language.web.xtext.server.push.PushWebDocumentProvider;
@@ -20,16 +21,20 @@ public class ProblemWebModule extends AbstractProblemWebModule {
         public Class<? extends IWebDocumentProvider> bindIWebDocumentProvider() {
                 return PushWebDocumentProvider.class;
         }
-        
+
         public Class<? extends XtextWebDocumentAccess> bindXtextWebDocumentAccess() {
                 return PushWebDocumentAccess.class;
         }
-        
+
         public Class<? extends XtextServiceDispatcher> bindXtextServiceDispatcher() {
                 return PushServiceDispatcher.class;
         }
-        
+
         public Class<? extends OccurrencesService> bindOccurrencesService() {
                 return ProblemOccurrencesService.class;
         }
+
+        public Class<? extends ExecutorServiceProvider> bindExecutorServiceProvider() {
+                return VirtualThreadExecutorServiceProvider.class;
+        }
 }
diff --git a/subprojects/language-web/src/main/java/tools/refinery/language/web/ServerLauncher.java b/subprojects/language-web/src/main/java/tools/refinery/language/web/ServerLauncher.java
index 58c8ea4e..5da16850 100644
--- a/subprojects/language-web/src/main/java/tools/refinery/language/web/ServerLauncher.java
+++ b/subprojects/language-web/src/main/java/tools/refinery/language/web/ServerLauncher.java
@@ -5,20 +5,21 @@ package tools.refinery.language.web;
 
 import jakarta.servlet.DispatcherType;
 import jakarta.servlet.SessionTrackingMode;
+import org.eclipse.jetty.ee10.servlet.DefaultServlet;
+import org.eclipse.jetty.ee10.servlet.ServletContextHandler;
+import org.eclipse.jetty.ee10.servlet.ServletHolder;
+import org.eclipse.jetty.ee10.servlet.SessionHandler;
+import org.eclipse.jetty.ee10.websocket.server.config.JettyWebSocketServletContainerInitializer;
 import org.eclipse.jetty.server.Server;
-import org.eclipse.jetty.server.session.SessionHandler;
-import org.eclipse.jetty.servlet.DefaultServlet;
-import org.eclipse.jetty.servlet.ServletContextHandler;
-import org.eclipse.jetty.servlet.ServletHolder;
+import org.eclipse.jetty.util.VirtualThreads;
 import org.eclipse.jetty.util.resource.Resource;
-import org.eclipse.jetty.websocket.server.config.JettyWebSocketServletContainerInitializer;
+import org.eclipse.jetty.util.resource.ResourceFactory;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import tools.refinery.language.web.config.BackendConfigServlet;
 import tools.refinery.language.web.xtext.servlet.XtextWebSocketServlet;
 
 import java.io.File;
-import java.io.IOException;
 import java.net.InetSocketAddress;
 import java.net.URI;
 import java.net.URISyntaxException;
@@ -42,13 +43,18 @@ public class ServerLauncher {
 
         private final Server server;
 
-        public ServerLauncher(InetSocketAddress bindAddress, Resource baseResource, String[] allowedOrigins,
-                                                  String webSocketUrl) {
+        public ServerLauncher(InetSocketAddress bindAddress, String[] allowedOrigins, String webSocketUrl) {
                 server = new Server(bindAddress);
+                if (server.getThreadPool() instanceof VirtualThreads.Configurable virtualThreadsConfigurable) {
+                        // Change this to setVirtualThreadsExecutor once
+                        // https://github.com/eclipse/jetty.project/commit/83154b4ffe4767ef44981598d6c26e6a5d32e57c gets released.
+                        virtualThreadsConfigurable.setUseVirtualThreads(VirtualThreads.areSupported());
+                }
                 var handler = new ServletContextHandler();
                 addSessionHandler(handler);
                 addProblemServlet(handler, allowedOrigins);
                 addBackendConfigServlet(handler, webSocketUrl);
+                var baseResource = getBaseResource();
                 if (baseResource != null) {
                         handler.setBaseResource(baseResource);
                         handler.setWelcomeFiles(new String[]{"index.html"});
@@ -95,6 +101,35 @@ public class ServerLauncher {
                 handler.addServlet(defaultServletHolder, "/");
         }
 
+        private Resource getBaseResource() {
+                var factory = ResourceFactory.of(server);
+                var baseResourceOverride = System.getenv("BASE_RESOURCE");
+                if (baseResourceOverride != null) {
+                        // If a user override is provided, use it.
+                        return factory.newResource(baseResourceOverride);
+                }
+                var indexUrlInJar = ServerLauncher.class.getResource("/webapp/index.html");
+                if (indexUrlInJar != null) {
+                        // If the app is packaged in the jar, serve it.
+                        URI webRootUri = null;
+                        try {
+                                webRootUri = URI.create(indexUrlInJar.toURI().toASCIIString().replaceFirst("/index.html$", "/"));
+                        } catch (URISyntaxException e) {
+                                throw new IllegalStateException("Jar has invalid base resource URI", e);
+                        }
+                        return factory.newResource(webRootUri);
+                }
+                // Look for unpacked production artifacts (convenience for running from IDE).
+                var unpackedResourcePathComponents = new String[]{System.getProperty("user.dir"), "build", "webpack",
+                                "production"};
+                var unpackedResourceDir = new File(String.join(File.separator, unpackedResourcePathComponents));
+                if (unpackedResourceDir.isDirectory()) {
+                        return factory.newResource(unpackedResourceDir.toPath());
+                }
+                // Fall back to just serving a 404.
+                return null;
+        }
+
         public void start() throws Exception {
                 server.start();
                 LOG.info("Server started on {}", server.getURI());
@@ -104,10 +139,9 @@ public class ServerLauncher {
         public static void main(String[] args) {
                 try {
                         var bindAddress = getBindAddress();
-                        var baseResource = getBaseResource();
                         var allowedOrigins = getAllowedOrigins();
                         var webSocketUrl = getWebSocketUrl();
-                        var serverLauncher = new ServerLauncher(bindAddress, baseResource, allowedOrigins, webSocketUrl);
+                        var serverLauncher = new ServerLauncher(bindAddress, allowedOrigins, webSocketUrl);
                         serverLauncher.start();
                 } catch (Exception exception) {
                         LOG.error("Fatal server error", exception);
@@ -137,29 +171,6 @@ public class ServerLauncher {
                 return new InetSocketAddress(listenAddress, listenPort);
         }
 
-        private static Resource getBaseResource() throws IOException, URISyntaxException {
-                var baseResourceOverride = System.getenv("BASE_RESOURCE");
-                if (baseResourceOverride != null) {
-                        // If a user override is provided, use it.
-                        return Resource.newResource(baseResourceOverride);
-                }
-                var indexUrlInJar = ServerLauncher.class.getResource("/webapp/index.html");
-                if (indexUrlInJar != null) {
-                        // If the app is packaged in the jar, serve it.
-                        var webRootUri = URI.create(indexUrlInJar.toURI().toASCIIString().replaceFirst("/index.html$", "/"));
-                        return Resource.newResource(webRootUri);
-                }
-                // Look for unpacked production artifacts (convenience for running from IDE).
-                var unpackedResourcePathComponents = new String[]{System.getProperty("user.dir"), "build", "webpack",
-                                "production"};
-                var unpackedResourceDir = new File(String.join(File.separator, unpackedResourcePathComponents));
-                if (unpackedResourceDir.isDirectory()) {
-                        return Resource.newResource(unpackedResourceDir);
-                }
-                // Fall back to just serving a 404.
-                return null;
-        }
-
         private static String getPublicHost() {
                 var publicHost = System.getenv("PUBLIC_HOST");
                 if (publicHost != null) {
diff --git a/subprojects/language-web/src/main/java/tools/refinery/language/web/xtext/VirtualThreadExecutorServiceProvider.java b/subprojects/language-web/src/main/java/tools/refinery/language/web/xtext/VirtualThreadExecutorServiceProvider.java
new file mode 100644
index 00000000..ead98927
--- /dev/null
+++ b/subprojects/language-web/src/main/java/tools/refinery/language/web/xtext/VirtualThreadExecutorServiceProvider.java
@@ -0,0 +1,20 @@
+package tools.refinery.language.web.xtext;
+
+import org.eclipse.xtext.ide.ExecutorServiceProvider;
+
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+
+public class VirtualThreadExecutorServiceProvider extends ExecutorServiceProvider {
+        private static final String THREAD_POOL_NAME = "xtextWeb";
+
+        @Override
+        protected ExecutorService createInstance(String key) {
+                var name = key == null ? THREAD_POOL_NAME : THREAD_POOL_NAME + "-" + key;
+                return Executors.newThreadPerTaskExecutor(Thread.ofVirtual()
+                                .allowSetThreadLocals(true)
+                                .inheritInheritableThreadLocals(false)
+                                .name(name + "-", 0)
+                                .factory());
+        }
+}
diff --git a/subprojects/language-web/src/main/java/tools/refinery/language/web/xtext/servlet/XtextWebSocket.java b/subprojects/language-web/src/main/java/tools/refinery/language/web/xtext/servlet/XtextWebSocket.java
index 82391d8b..1d9e0463 100644
--- a/subprojects/language-web/src/main/java/tools/refinery/language/web/xtext/servlet/XtextWebSocket.java
+++ b/subprojects/language-web/src/main/java/tools/refinery/language/web/xtext/servlet/XtextWebSocket.java
@@ -3,10 +3,10 @@ package tools.refinery.language.web.xtext.servlet;
 import com.google.gson.Gson;
 import com.google.gson.JsonIOException;
 import com.google.gson.JsonParseException;
-import org.eclipse.jetty.websocket.api.Session;
-import org.eclipse.jetty.websocket.api.StatusCode;
-import org.eclipse.jetty.websocket.api.WriteCallback;
-import org.eclipse.jetty.websocket.api.annotations.*;
+import org.eclipse.jetty.ee10.websocket.api.Session;
+import org.eclipse.jetty.ee10.websocket.api.StatusCode;
+import org.eclipse.jetty.ee10.websocket.api.WriteCallback;
+import org.eclipse.jetty.ee10.websocket.api.annotations.*;
 import org.eclipse.xtext.resource.IResourceServiceProvider;
 import org.eclipse.xtext.web.server.ISession;
 import org.slf4j.Logger;
@@ -17,7 +17,6 @@ import tools.refinery.language.web.xtext.server.TransactionExecutor;
 import tools.refinery.language.web.xtext.server.message.XtextWebRequest;
 import tools.refinery.language.web.xtext.server.message.XtextWebResponse;
 
-import java.io.IOException;
 import java.io.Reader;
 
 @WebSocket
@@ -108,12 +107,7 @@ public class XtextWebSocket implements WriteCallback, ResponseHandler {
                         throw new ResponseHandlerException("Trying to send message when websocket is disconnected");
                 }
                 var responseString = gson.toJson(response);
-                try {
-                        webSocketSession.getRemote().sendPartialString(responseString, true, this);
-                } catch (IOException e) {
-                        throw new ResponseHandlerException(
-                                        "Cannot initiate async write to websocket " + webSocketSession.getRemoteAddress(), e);
-                }
+                webSocketSession.getRemote().sendPartialString(responseString, true, this);
         }
 
         @Override
diff --git a/subprojects/language-web/src/main/java/tools/refinery/language/web/xtext/servlet/XtextWebSocketServlet.java b/subprojects/language-web/src/main/java/tools/refinery/language/web/xtext/servlet/XtextWebSocketServlet.java
index a2ad2943..9a32b937 100644
--- a/subprojects/language-web/src/main/java/tools/refinery/language/web/xtext/servlet/XtextWebSocketServlet.java
+++ b/subprojects/language-web/src/main/java/tools/refinery/language/web/xtext/servlet/XtextWebSocketServlet.java
@@ -2,7 +2,7 @@ package tools.refinery.language.web.xtext.servlet;
 
 import jakarta.servlet.ServletConfig;
 import jakarta.servlet.ServletException;
-import org.eclipse.jetty.websocket.server.*;
+import org.eclipse.jetty.ee10.websocket.server.*;
 import org.eclipse.xtext.resource.IResourceServiceProvider;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;