Merge pull request #753 from christianlouis/copilot/scale-worker-and-api-pods

feat(scaling): enable horizontal scaling for API and worker pods

app/api/diagnostic.py

@@ -21,6 +21,67 @@ _DEFAULT_REDIS_URL = "redis://localhost:6379/0"
 
 router = APIRouter()
 
+# ---------------------------------------------------------------------------
+# Unauthenticated probe endpoints for Kubernetes liveness / readiness checks.
+# These intentionally skip authentication so that kubelet can reach them
+# without credentials.  They live under /diagnostic/healthz/* so that the
+# existing authenticated /diagnostic/health endpoint is unaffected.
+# ---------------------------------------------------------------------------
+
+
+@router.get("/diagnostic/healthz/live")
+async def liveness_probe() -> JSONResponse:
+    """Lightweight liveness probe for Kubernetes.
+
+    Returns **200 OK** as long as the process is running.  Kubernetes uses
+    this to decide whether to *restart* the container — it should therefore
+    be as cheap as possible and **never** check external dependencies.
+
+    **Authentication:** None (designed for kubelet probes).
+    """
+    return JSONResponse(content={"status": "ok"}, status_code=200)
+
+
+@router.get("/diagnostic/healthz/ready")
+async def readiness_probe() -> JSONResponse:
+    """Readiness probe for Kubernetes.
+
+    Verifies that the application can serve traffic by checking the database
+    and Redis.  Kubernetes uses this to decide whether to *route traffic* to
+    the pod.
+
+    Returns **200 OK** when all critical subsystems are reachable, or
+    **503 Service Unavailable** when the database is down.
+
+    **Authentication:** None (designed for kubelet probes).
+    """
+    checks: dict[str, dict[str, str]] = {}
+    db_ok = False
+
+    # ── Database check ─────────────────────────────────────────────────
+    try:
+        with engine.connect() as conn:
+            conn.execute(text("SELECT 1"))
+        checks["database"] = {"status": "ok"}
+        db_ok = True
+    except Exception as exc:
+        logger.warning("Readiness probe: database check failed: %s", exc)
+        checks["database"] = {"status": "error", "detail": str(exc)}
+
+    # ── Redis check ────────────────────────────────────────────────────
+    try:
+        redis_url = settings.redis_url or _DEFAULT_REDIS_URL
+        r = redis_lib.from_url(redis_url, socket_connect_timeout=2, socket_timeout=2)
+        r.ping()
+        checks["redis"] = {"status": "ok"}
+    except Exception as exc:
+        logger.warning("Readiness probe: Redis check failed: %s", exc)
+        checks["redis"] = {"status": "error", "detail": str(exc)}
+
+    http_status = 503 if not db_ok else 200
+    overall = "ready" if db_ok else "not_ready"
+    return JSONResponse(content={"status": overall, "checks": checks}, status_code=http_status)
+
 
 @router.get("/diagnostic/health")
 @require_login