perf: Prewarm LiveAvatar browser sessions

app-config.ts

@@ -220,9 +220,9 @@ export const APP_CONFIG_DEFAULTS: AppConfig = {
   remoteVideoHeight: 480,
   remoteVideoFps: 25,
 
-  logo: '/lk-logo.png',
+  logo: 'lk-logo.png',
   accent: '#002cf2',
-  logoDark: '/lk-logo-dark.png',
+  logoDark: 'lk-logo-dark.png',
   accentDark: '#1fd5f9',
   startButtonText: 'Start call',
 

app/api/session/agent-worker-readiness.ts

@@ -0,0 +1,129 @@
+import { readFile } from 'node:fs/promises';
+import path from 'node:path';
+
+const DEFAULT_READY_TIMEOUT_MS = 30_000;
+const DEFAULT_READY_POLL_MS = 200;
+
+type AgentWorkerReadyMarker = {
+  version: number;
+  agentName: string;
+  workerId: string;
+  registeredAt: string;
+};
+
+export type WaitForAgentWorkerReadyOptions = {
+  readyFile?: string;
+  timeoutMs?: number;
+  maxWaitMs?: number;
+  pollMs?: number;
+  readFile?: (filePath: string) => Promise<string>;
+  sleep?: (ms: number) => Promise<unknown>;
+};
+
+export type AgentWorkerReadiness =
+  | {
+      state: 'ready';
+      agentName: string;
+      workerId: string;
+      registeredAt: string;
+      waitedMs: number;
+    }
+  | {
+      state: 'skipped';
+      agentName: string;
+      reason: 'not_sandbox';
+      waitedMs: 0;
+    };
+
+export function resolveAgentWorkerReadyFile(env: NodeJS.ProcessEnv = process.env): string {
+  const configured = (env.LIVEAVATAR_AGENT_WORKER_READY_FILE || '').trim();
+  if (configured) {
+    return configured;
+  }
+  if ((env.LIVEAVATAR_RUNTIME_MODE || '').trim().toLowerCase() !== 'sandbox') {
+    return '';
+  }
+  const workspaceDataDir = (env.LIVEAVATAR_SANDBOX_WORKSPACE_DATA_DIR || '/workspace/data').trim();
+  return workspaceDataDir
+    ? path.join(workspaceDataDir, 'logs', 'sandbox', 'agent-worker-ready.json')
+    : '';
+}
+
+export function resolveAgentWorkerReadyTimeoutMs(env: NodeJS.ProcessEnv = process.env): number {
+  return readPositiveInt(env.LIVEAVATAR_AGENT_WORKER_READY_TIMEOUT_MS, DEFAULT_READY_TIMEOUT_MS);
+}
+
+export async function waitForAgentWorkerReady(
+  agentName: string,
+  options: WaitForAgentWorkerReadyOptions = {}
+): Promise<AgentWorkerReadiness> {
+  const readyFile = options.readyFile ?? resolveAgentWorkerReadyFile();
+  if (!readyFile) {
+    return { state: 'skipped', agentName, reason: 'not_sandbox', waitedMs: 0 };
+  }
+
+  const configuredTimeoutMs = options.timeoutMs ?? resolveAgentWorkerReadyTimeoutMs();
+  const timeoutMs =
+    options.maxWaitMs === undefined
+      ? configuredTimeoutMs
+      : Math.max(0, Math.min(configuredTimeoutMs, options.maxWaitMs));
+  if (timeoutMs <= 0) {
+    throw new Error(`agent worker did not register before prewarm timeout: ${agentName}`);
+  }
+  const pollMs =
+    options.pollMs ??
+    readPositiveInt(process.env.LIVEAVATAR_AGENT_WORKER_READY_POLL_MS, DEFAULT_READY_POLL_MS);
+  const readMarkerFile = options.readFile || ((filePath: string) => readFile(filePath, 'utf8'));
+  const sleepFn = options.sleep || sleep;
+  const startedAt = Date.now();
+  const deadline = startedAt + timeoutMs;
+
+  do {
+    const marker = await readReadyMarker(readyFile, readMarkerFile);
+    if (marker?.agentName === agentName && marker.workerId) {
+      return {
+        state: 'ready',
+        agentName,
+        workerId: marker.workerId,
+        registeredAt: marker.registeredAt,
+        waitedMs: Date.now() - startedAt,
+      };
+    }
+
+    const waitMs = Math.min(pollMs, deadline - Date.now());
+    if (waitMs > 0) {
+      await sleepFn(waitMs);
+    }
+  } while (Date.now() < deadline);
+
+  throw new Error(`agent worker did not register before prewarm timeout: ${agentName}`);
+}
+
+async function readReadyMarker(
+  readyFile: string,
+  readMarkerFile: (filePath: string) => Promise<string>
+): Promise<AgentWorkerReadyMarker | null> {
+  try {
+    const payload = JSON.parse(await readMarkerFile(readyFile)) as Partial<AgentWorkerReadyMarker>;
+    if (
+      payload.version !== 1 ||
+      typeof payload.agentName !== 'string' ||
+      typeof payload.workerId !== 'string' ||
+      typeof payload.registeredAt !== 'string'
+    ) {
+      return null;
+    }
+    return payload as AgentWorkerReadyMarker;
+  } catch {
+    return null;
+  }
+}
+
+function readPositiveInt(value: string | undefined, fallback: number): number {
+  const parsed = Number.parseInt(String(value || ''), 10);
+  return Number.isFinite(parsed) && parsed > 0 ? parsed : fallback;
+}
+
+function sleep(ms: number): Promise<void> {
+  return new Promise((resolve) => setTimeout(resolve, ms));
+}