fix: apply backoff to watchdog reconnects

apps/client/src/common/utils/__tests__/socket.test.ts

@@ -59,6 +59,7 @@ vi.mock('../../stores/logger', () => ({ addLog: vi.fn() }));
 
 describe('socket connection watchdog', () => {
   let connectSocket: () => void;
+  let getReconnectAttempts: () => number;
 
   beforeEach(async () => {
     vi.useFakeTimers();
@@ -67,7 +68,9 @@ describe('socket connection watchdog', () => {
     vi.stubGlobal('WebSocket', MockWebSocket);
     // the module keeps connection state in module scope, we need a clean one for each test
     vi.resetModules();
-    connectSocket = (await import('../socket')).connectSocket;
+    const socketModule = await import('../socket');
+    connectSocket = socketModule.connectSocket;
+    getReconnectAttempts = socketModule.getReconnectAttempts;
   });
 
   afterEach(() => {
@@ -108,10 +111,12 @@ describe('socket connection watchdog', () => {
 
     vi.advanceTimersByTime(watchdogInterval);
     expect(socket.readyState).toBe(MockWebSocket.CLOSED);
+
+    vi.advanceTimersByTime(socketConfig.reconnectBaseInterval * 2);
     expect(MockWebSocket.instances).toHaveLength(2);
   });
 
-  it('gives up on a connection attempt which never completes', () => {
+  it('backs off after a connection attempt which never completes', () => {
     connectSocket();
     const socket = MockWebSocket.instances[0];
 
@@ -119,7 +124,12 @@ describe('socket connection watchdog', () => {
     vi.advanceTimersByTime(connectTimeout + watchdogInterval);
 
     expect(socket.readyState).toBe(MockWebSocket.CLOSED);
+    expect(MockWebSocket.instances).toHaveLength(1);
+    expect(getReconnectAttempts()).toBe(0);
+
+    vi.advanceTimersByTime(socketConfig.reconnectBaseInterval * 2);
     expect(MockWebSocket.instances).toHaveLength(2);
+    expect(getReconnectAttempts()).toBe(1);
   });
 
   it('logs one warning while repeated connection attempts time out', () => {
@@ -164,6 +174,7 @@ describe('socket connection watchdog', () => {
     const stale = openConnection();
 
     vi.advanceTimersByTime(silenceTimeout + watchdogInterval);
+    vi.advanceTimersByTime(socketConfig.reconnectBaseInterval * 2);
     expect(MockWebSocket.instances).toHaveLength(2);
     MockWebSocket.instances[1].open();
 

apps/client/src/common/utils/socket.ts

@@ -276,14 +276,11 @@ function scheduleReconnect() {
   }, delay);
 }
 
-/**
- * Drops the current connection and immediately opens a new one.
- * Used when we have reason to believe the socket is no longer delivering data.
- */
-function reconnectNow(reason: string) {
+/** Drops a socket that is no longer delivering and retries with the normal backoff. */
+function reconnectWithBackoff(reason: string) {
   logConnectionIssue(reason);
   detachSocket();
-  connectSocket();
+  scheduleReconnect();
 }
 
 /** Detaches a socket before closing it so late events cannot affect its replacement. */
@@ -325,23 +322,19 @@ function checkConnection() {
   if (websocket?.readyState === WebSocket.CONNECTING) {
     // A connection attempt can otherwise hang indefinitely.
     if (silentFor > socketConfig.connectTimeout) {
-      reconnectNow('WebSocket: connection attempt timed out');
+      reconnectWithBackoff('WebSocket: connection attempt timed out');
     }
     return;
   }
 
   if (websocket?.readyState === WebSocket.OPEN) {
     if (silentFor > socketConfig.silenceTimeout) {
-      reconnectNow('WebSocket: no data from server, reconnecting');
+      reconnectWithBackoff('WebSocket: no data from server, reconnecting');
     }
     return;
   }
 
-  /**
-   * The socket is closing, closed or was never created.
-   * Closing schedules its own reconnect, this is what covers us if that did not happen,
-   * so that there is no state the client can settle in without a way out.
-   */
+  // Covers a close event that the browser never reported.
   if (!reconnectTimeout) {
     scheduleReconnect();
   }