merge: testing → main (reconcile 2-week divergence)

decnet/web/router/stats/api_get_stats.py

@@ -1,14 +1,50 @@
-from typing import Any
+import asyncio
+import time
+from typing import Any, Optional
 
 from fastapi import APIRouter, Depends
 
-from decnet.web.dependencies import get_current_user, repo
+from decnet.telemetry import traced as _traced
+from decnet.web.dependencies import require_viewer, repo
 from decnet.web.db.models import StatsResponse
 
 router = APIRouter()
 
+# /stats is aggregate telemetry polled constantly by the UI and locust.
+# A 5s window collapses thousands of concurrent calls — each of which
+# runs SELECT count(*) FROM logs + SELECT count(DISTINCT attacker_ip) —
+# into one DB hit per window.
+_STATS_TTL = 5.0
+_stats_cache: tuple[Optional[dict[str, Any]], float] = (None, 0.0)
+_stats_lock: Optional[asyncio.Lock] = None
+
+
+def _reset_stats_cache() -> None:
+    global _stats_cache, _stats_lock
+    _stats_cache = (None, 0.0)
+    _stats_lock = None
+
+
+async def _get_stats_cached() -> dict[str, Any]:
+    global _stats_cache, _stats_lock
+    value, ts = _stats_cache
+    now = time.monotonic()
+    if value is not None and now - ts < _STATS_TTL:
+        return value
+    if _stats_lock is None:
+        _stats_lock = asyncio.Lock()
+    async with _stats_lock:
+        value, ts = _stats_cache
+        now = time.monotonic()
+        if value is not None and now - ts < _STATS_TTL:
+            return value
+        value = await repo.get_stats_summary()
+        _stats_cache = (value, time.monotonic())
+        return value
+
 
 @router.get("/stats", response_model=StatsResponse, tags=["Observability"],
-    responses={401: {"description": "Could not validate credentials"}, 422: {"description": "Validation error"}},)
-async def get_stats(current_user: str = Depends(get_current_user)) -> dict[str, Any]:
-    return await repo.get_stats_summary()
+    responses={401: {"description": "Could not validate credentials"}, 403: {"description": "Insufficient permissions"}, 422: {"description": "Validation error"}},)
+@_traced("api.get_stats")
+async def get_stats(user: dict = Depends(require_viewer)) -> dict[str, Any]:
+    return await _get_stats_cached()