fix(ui): add retry logic to SSE pong to improve connection resilience

packages/ui/src/lib/retry-utils.ts

@@ -0,0 +1,38 @@
+interface RetryOptions {
+  maxAttempts?: number
+  initialDelayMs?: number
+  maxDelayMs?: number
+  backoffMultiplier?: number
+}
+
+export async function retryWithBackoff<T>(
+  fn: () => Promise<T>,
+  options: RetryOptions = {},
+): Promise<T> {
+  const {
+    maxAttempts = 3,
+    initialDelayMs = 100,
+    maxDelayMs = 5000,
+    backoffMultiplier = 2,
+  } = options
+
+  let lastError: Error | null = null
+  let delayMs = initialDelayMs
+
+  for (let attempt = 1; attempt <= maxAttempts; attempt++) {
+    try {
+      return await fn()
+    } catch (error) {
+      lastError = error instanceof Error ? error : new Error(String(error))
+
+      if (attempt < maxAttempts) {
+        await new Promise((resolve) => setTimeout(resolve, delayMs))
+        delayMs = Math.min(delayMs * backoffMultiplier, maxDelayMs)
+      }
+    }
+  }
+
+  throw new Error(
+    `Failed after ${maxAttempts} attempts: ${lastError?.message || "Unknown error"}`,
+  )
+}

packages/ui/src/lib/server-events.ts

@@ -2,6 +2,7 @@ import type { WorkspaceEventPayload, WorkspaceEventType } from "../../../server/
 import { serverApi } from "./api-client"
 import { getClientIdentity } from "./client-identity"
 import { getLogger } from "./logger"
+import { retryWithBackoff } from "./retry-utils"
 
 const RETRY_BASE_DELAY = 1000
 const RETRY_MAX_DELAY = 10000
@@ -39,14 +40,19 @@ class ServerEvents {
       (event) => this.dispatch(event),
       () => this.scheduleReconnect(),
       (payload) => {
-        void serverApi
-          .sendClientConnectionPong({
-            ...getClientIdentity(),
-            pingTs: payload.ts,
-          })
-          .catch((error) => {
-            log.error("Failed to send client connection pong", error)
-          })
+        const identity = getClientIdentity()
+        const pongPayload = { ...identity, pingTs: payload.ts }
+
+        void retryWithBackoff(
+          () => serverApi.sendClientConnectionPong(pongPayload),
+          {
+            maxAttempts: 3,
+            initialDelayMs: 100,
+            maxDelayMs: 2000,
+          },
+        ).catch((error) => {
+          log.error("Failed to send client connection pong after retries", error)
+        })
       },
     )
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