M35: harden the shared public demo

backend/app/services/integration_status.py

@@ -1,5 +1,7 @@
 from __future__ import annotations
 
+import threading
+import time
 from datetime import UTC, datetime, timedelta
 from typing import Literal
 
@@ -18,6 +20,9 @@ from app.schemas import (
 )
 
 settings = get_settings()
+_hub_health_lock = threading.Lock()
+_hub_health_cached_at = 0.0
+_hub_health_cached_value: bool | None = None
 
 # The 4 canonical Fleet Ops n8n workflows (see n8n/workflows/MANIFEST.md). All 4 are
 # built (all with their full node set saved).
@@ -278,8 +283,15 @@ def _check_hub_reachable() -> bool | None:
     `None` means not configured / not checked, never a guess."""
     if not settings.mcp_hub_base_url:
         return None
-    try:
-        response = httpx.get(f"{settings.mcp_hub_base_url.rstrip('/')}/health", timeout=1.5)
-        return response.status_code == 200
-    except httpx.HTTPError:
-        return False
+    global _hub_health_cached_at, _hub_health_cached_value
+    now = time.monotonic()
+    with _hub_health_lock:
+        if now - _hub_health_cached_at < settings.mcp_hub_health_cache_seconds:
+            return _hub_health_cached_value
+        try:
+            response = httpx.get(f"{settings.mcp_hub_base_url.rstrip('/')}/health", timeout=1.5)
+            _hub_health_cached_value = response.status_code == 200
+        except httpx.HTTPError:
+            _hub_health_cached_value = False
+        _hub_health_cached_at = time.monotonic()
+        return _hub_health_cached_value