feat(api): add keep-alive endpoints for Supabase and Vercel cold-start mitigation

Author: sanjeevafk

api/main.py

@@ -5,27 +5,27 @@
 import time
 import structlog
 from contextlib import asynccontextmanager
-from fastapi import FastAPI, Request
+from fastapi import FastAPI, Request, Response
 from fastapi.middleware.cors import CORSMiddleware
 from fastapi.responses import JSONResponse
 from slowapi import Limiter
 from slowapi.errors import RateLimitExceeded
 from slowapi.middleware import SlowAPIMiddleware
 from slowapi.util import get_remote_address
-from routers import (
-    pinned,
-    query,
-    export,
-    history,
-    webhooks,
-    payments,
-    messages,
-    analytics,
-    legal,
-    seo,
-    emails,
-    shares,
-)
+from routers import (
+    pinned,
+    query,
+    export,
+    history,
+    webhooks,
+    payments,
+    messages,
+    analytics,
+    legal,
+    seo,
+    emails,
+    shares,
+)
 from auth import get_supabase_admin
 from services.cache import close_redis, get_redis
 from services.inference import close_client
@@ -334,11 +334,11 @@ async def llm_error_handler(request: Request, exc: LLMError):
 app.include_router(history.router, prefix="/api")
 app.include_router(analytics.router, prefix="/api")
 app.include_router(legal.router, prefix="/api")
-app.include_router(seo.router)
-app.include_router(emails.router, prefix="/api")
-app.include_router(webhooks.router)  # No prefix - webhooks use full path
-app.include_router(payments.router, prefix="/api")
-app.include_router(shares.router, prefix="/api")
+app.include_router(seo.router)
+app.include_router(emails.router, prefix="/api")
+app.include_router(webhooks.router)  # No prefix - webhooks use full path
+app.include_router(payments.router, prefix="/api")
+app.include_router(shares.router, prefix="/api")
 
 
 @app.get("/api/health", tags=["health"])
@@ -378,6 +378,7 @@ async def check_rate_limit() -> dict[str, str]:
             log_fn("rate_limit_health_probe_failed", severity="error" if is_prod else "warning", error=str(exc))
             return {"status": status}
 
+
     async def check_db() -> dict[str, str]:
         try:
             if not settings.supabase_url or not settings.supabase_secret_key:
@@ -416,6 +417,36 @@ async def check_db() -> dict[str, str]:
     }
 
 
+@app.get("/api/keep-alive", tags=["health"])
+async def keep_alive(request: Request):
+    """Minimal keep-alive endpoint for Supabase and Vercel cold-start mitigation."""
+    cron_secret = os.getenv("CRON_SECRET")
+    if cron_secret:
+        provided = request.query_params.get("key")
+        if not provided or provided != cron_secret:
+            return JSONResponse(status_code=401, content={"error": "unauthorized"})
+
+    supabase = get_supabase_admin()
+    if not supabase:
+        return JSONResponse(status_code=503, content={"error": "supabase_unavailable"})
+
+    await asyncio.to_thread(
+        lambda: supabase.table("conversations").select("id").limit(1).execute()
+    )
+    return JSONResponse(status_code=200, content={"ok": True})
+
+
+@app.head("/api/keep-alive", tags=["health"])
+async def keep_alive_head(request: Request):
+    """HEAD variant that avoids Supabase calls."""
+    cron_secret = os.getenv("CRON_SECRET")
+    if cron_secret:
+        provided = request.query_params.get("key")
+        if not provided or provided != cron_secret:
+            return Response(status_code=401)
+    return Response(status_code=200)
+
+
 # Catch-all route for debugging (should be last)
 @app.api_route("/{path:path}", methods=["GET", "POST", "PUT", "PATCH", "DELETE"])
 async def catch_all(request: Request, path: str):