Define hudsonUrl in WebSocket mode to fix agent installers

src/main/java/hudson/remoting/Engine.java

@@ -30,6 +30,7 @@
 import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.net.HttpURLConnection;
+import java.net.MalformedURLException;
 import java.net.Socket;
 import java.net.URI;
 import java.net.URL;
@@ -61,6 +62,7 @@
 import java.util.concurrent.atomic.AtomicReference;
 import java.util.logging.Level;
 import java.util.logging.Logger;
+import java.util.stream.Collectors;
 import javax.annotation.CheckForNull;
 import javax.annotation.Nonnull;
 import javax.annotation.concurrent.NotThreadSafe;
@@ -243,7 +245,7 @@ public Engine(EngineListener listener, List<URL> hudsonUrls, String secretKey, S
  this.listener = listener;
  this.directConnection = directConnection;
  this.events.add(listener);
- this.candidateUrls = hudsonUrls;
+ this.candidateUrls = hudsonUrls.stream().map(Engine::ensureTrailingSlash).collect(Collectors.toList());
  this.secretKey = secretKey;
  this.agentName = agentName;
  this.instanceIdentity = instanceIdentity;
@@ -257,6 +259,18 @@ public Engine(EngineListener listener, List<URL> hudsonUrls, String secretKey, S
  });
  }
 
+ private static URL ensureTrailingSlash(URL u) {
+ if (u.toString().endsWith("/")) {
+ return u;
+ } else {
+ try {
+ return new URL(u + "/");
+ } catch (MalformedURLException x) {
+ throw new IllegalArgumentException(x);
+ }
+ }
+ }
+
  /**
  * Starts the engine.
  * The procedure initializes the working directory and all the required environment
@@ -623,8 +637,8 @@ public void closeRead() throws IOException {
  }
  }
  }
- String wsUrl = candidateUrls.get(0).toString().replaceFirst("^http", "ws");
- if(!wsUrl.endsWith("/")) wsUrl += "/";
+ hudsonUrl = candidateUrls.get(0);
+ String wsUrl = hudsonUrl.toString().replaceFirst("^http", "ws");
  ContainerProvider.getWebSocketContainer().connectToServer(new AgentEndpoint(),
  ClientEndpointConfig.Builder.create().configurator(headerHandler).build(), URI.create(wsUrl + "wsagents/"));
  while (ch.get() == null) {
@@ -640,7 +654,7 @@ public void closeRead() throws IOException {
  events.onDisconnect();
  while (true) {
  // Unlike JnlpAgentEndpointResolver, we do not use $jenkins/tcpSlaveAgentListener/, as that will be a 404 if the TCP port is disabled.
- URL ping = new URL(candidateUrls.get(0), "login");
+ URL ping = new URL(hudsonUrl, "login");
  try {
  HttpURLConnection conn = (HttpURLConnection) ping.openConnection();
  int status = conn.getResponseCode();

src/main/java/org/jenkinsci/remoting/engine/JnlpAgentEndpointResolver.java

@@ -376,9 +376,7 @@ private boolean isPortVisible(String hostname, int port) {
 
  @Nonnull
  private URL toAgentListenerURL(@Nonnull String jenkinsUrl) throws MalformedURLException {
- return jenkinsUrl.endsWith("/")
- ? new URL(jenkinsUrl + "tcpSlaveAgentListener/")
- : new URL(jenkinsUrl + "/tcpSlaveAgentListener/");
+ return new URL(jenkinsUrl + "tcpSlaveAgentListener/");
  }
 
  @Override