ArcpJettyServer.java

package dev.arcp.runtime.jetty;

import dev.arcp.runtime.ArcpRuntime;
import jakarta.websocket.server.ServerEndpointConfig;
import java.net.URI;
import java.util.List;
import java.util.Objects;
import org.eclipse.jetty.ee10.servlet.ServletContextHandler;
import org.eclipse.jetty.ee10.websocket.jakarta.server.config.JakartaWebSocketServletContainerInitializer;
import org.eclipse.jetty.server.Server;
import org.eclipse.jetty.server.ServerConnector;
import org.eclipse.jetty.util.thread.VirtualThreadPool;

/** Embedded Jetty 12 server exposing an ARCP runtime over {@code /arcp} as a WebSocket endpoint. */
public final class ArcpJettyServer implements AutoCloseable {

  private final ArcpRuntime runtime;
  private final String path;
  private final int port;
  private final Server server;

  private ArcpJettyServer(Builder b) {
    this.runtime = Objects.requireNonNull(b.runtime, "runtime");
    this.path = b.path;
    this.port = b.port;
    VirtualThreadPool pool = new VirtualThreadPool();
    this.server = new Server(pool);
    ServerConnector connector = new ServerConnector(server);
    connector.setPort(port);
    server.addConnector(connector);

    ServletContextHandler context = new ServletContextHandler("/");
    server.setHandler(context);

    JakartaWebSocketServletContainerInitializer.configure(
        context,
        (servletContext, container) -> {
          ServerEndpointConfig endpointConfig =
              ServerEndpointConfig.Builder.create(ArcpJettyEndpoint.class, path)
                  .configurator(
                      new ServerEndpointConfig.Configurator() {
                        @Override
                        public <T> T getEndpointInstance(Class<T> endpointClass) {
                          return endpointClass.cast(new ArcpJettyEndpoint());
                        }
                      })
                  .build();
          endpointConfig.getUserProperties().put(ArcpJettyEndpoint.RUNTIME_KEY, runtime);
          container.addEndpoint(endpointConfig);
        });
  }

  public static Builder builder(ArcpRuntime runtime) {
    return new Builder(runtime);
  }

  public ArcpJettyServer start() throws Exception {
    server.start();
    return this;
  }

  public URI uri() {
    int boundPort = ((ServerConnector) server.getConnectors()[0]).getLocalPort();
    return URI.create("ws://127.0.0.1:" + boundPort + path);
  }

  public int port() {
    return ((ServerConnector) server.getConnectors()[0]).getLocalPort();
  }

  @Override
  public void close() throws Exception {
    server.stop();
  }

  public static final class Builder {
    private final ArcpRuntime runtime;
    private String path = "/arcp";
    private int port = 0;
    private List<String> allowedHosts = List.of();

    Builder(ArcpRuntime runtime) {
      this.runtime = runtime;
    }

    public Builder path(String path) {
      this.path = path;
      return this;
    }

    public Builder port(int port) {
      this.port = port;
      return this;
    }

    public Builder allowedHosts(List<String> hosts) {
      this.allowedHosts = List.copyOf(hosts);
      return this;
    }

    public ArcpJettyServer build() {
      return new ArcpJettyServer(this);
    }
  }
}