fix: stabilize webvnc reconnects

internal/cli/daemon_unix.go

@@ -3,6 +3,7 @@
 package cli
 
 import (
+	"os"
 	"os/exec"
 	"syscall"
 )
@@ -10,3 +11,14 @@ import (
 func configureDaemonCommand(cmd *exec.Cmd) {
 	cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
 }
+
+func stopDaemonProcess(process *os.Process) error {
+	if process == nil {
+		return nil
+	}
+	err := syscall.Kill(-process.Pid, syscall.SIGTERM)
+	if err == syscall.ESRCH {
+		return nil
+	}
+	return err
+}

internal/cli/daemon_windows.go

@@ -2,6 +2,16 @@
 
 package cli
 
-import "os/exec"
+import (
+	"os"
+	"os/exec"
+)
 
 func configureDaemonCommand(_ *exec.Cmd) {}
+
+func stopDaemonProcess(process *os.Process) error {
+	if process == nil {
+		return nil
+	}
+	return process.Kill()
+}

internal/cli/webvnc.go

@@ -194,7 +194,7 @@ func (a App) startWebVNCDaemon(args []string, leaseID string) error {
 		return exit(5, "release WebVNC daemon process: %v", err)
 	}
 	fmt.Fprintf(a.Stdout, "webvnc daemon: pid=%d log=%s\n", pid, logPath)
-	fmt.Fprintf(a.Stdout, "webvnc daemon: stop with kill $(cat %s)\n", pidPath)
+	fmt.Fprintln(a.Stdout, "webvnc daemon: stop with crabbox webvnc --id <lease-id-or-slug> --stop")
 	return nil
 }
 
@@ -277,7 +277,7 @@ func (a App) stopWebVNCDaemon(leaseID string) error {
 	if err != nil {
 		return exit(5, "find WebVNC daemon pid %d: %v", pid, err)
 	}
-	if err := process.Kill(); err != nil {
+	if err := stopDaemonProcess(process); err != nil {
 		return exit(5, "stop WebVNC daemon pid %d: %v", pid, err)
 	}
 	_ = os.Remove(pidPath)

worker/src/fleet.ts

@@ -1226,14 +1226,12 @@ export class FleetDurableObject implements DurableObject {
       );
     }
     const existingViewer = this.webVNCViewers.get(lease.id);
-    if (existingViewer) {
-      closeSocket(existingViewer, 1012, "replaced by a newer WebVNC viewer");
-      this.clearWebVNCViewer(lease.id, existingViewer);
+    if (existingViewer?.readyState === WebSocket.OPEN) {
       const command = webVNCBridgeCommand(lease);
       return json(
         {
-          error: "webvnc_bridge_reset",
-          message: `another viewer was active; restart or wait for the bridge to reconnect with: ${command}`,
+          error: "webvnc_viewer_active",
+          message: `another viewer is active; close stale WebVNC tabs or wait before reconnecting with: ${command}`,
           command,
         },
         { status: 409 },

worker/src/portal.ts

@@ -231,10 +231,10 @@ export function portalVNC(lease: LeaseRecord): Response {
             return;
           }
           if (state?.viewerConnected) {
-            setStatus("another viewer is connected; close stale tabs if this resets", "warn");
-          } else {
-            setStatus(retryAttempt ? "bridge connected; opening viewer" : "connecting");
+            scheduleRetry("another viewer is connected; close stale WebVNC tabs");
+            return;
           }
+          setStatus(retryAttempt ? "bridge connected; opening viewer" : "connecting");
           rfb = new RFB(screen, wsURL.toString(), options);
           rfb.scaleViewport = true;
           rfb.resizeSession = false;

worker/test/fleet.test.ts

@@ -745,6 +745,7 @@ describe("fleet lease identity and idle", () => {
     expect(pageBody).toContain("/portal/leases/cbx_000000000001/vnc/status");
     expect(pageBody).toContain("vnc-copy");
     expect(pageBody).toContain("no bridge connected; run the bridge command below");
+    expect(pageBody).toContain("another viewer is connected; close stale WebVNC tabs");
     expect(pageBody).toContain('fragment.get("username")');
     expect(pageBody).toContain('types.includes("username")');
     expect(pageBody).not.toContain("cdn.jsdelivr.net");