Update engine protocol

engine/app/backend_client.py

@@ -0,0 +1,44 @@
+"""Backend API client for assistant config."""
+
+from __future__ import annotations
+
+from typing import Any, Dict, Optional
+
+import aiohttp
+from loguru import logger
+
+from app.config import settings
+
+
+async def fetch_assistant_config(assistant_id: str) -> Optional[Dict[str, Any]]:
+    """Fetch assistant config payload from backend API.
+
+    Expected response shape:
+    {
+      "assistant": {...},
+      "voice": {...} | null
+    }
+    """
+    if not settings.backend_url:
+        logger.warning("BACKEND_URL not set; skipping assistant config fetch")
+        return None
+
+    url = f"{settings.backend_url.rstrip('/')}/api/assistants/{assistant_id}/config"
+    timeout = aiohttp.ClientTimeout(total=settings.backend_timeout_sec)
+
+    try:
+        async with aiohttp.ClientSession(timeout=timeout) as session:
+            async with session.get(url) as resp:
+                if resp.status == 404:
+                    logger.warning(f"Assistant config not found: {assistant_id}")
+                    return None
+                resp.raise_for_status()
+                payload = await resp.json()
+                if not isinstance(payload, dict):
+                    logger.warning("Assistant config payload is not a dict; ignoring")
+                    return None
+                return payload
+    except Exception as exc:
+        logger.warning(f"Failed to fetch assistant config ({assistant_id}): {exc}")
+        return None
+