Add 'fiscal/' from commit '102ba84500dbd9655a0471288c3e278652593ca9'

git-subtree-dir: fiscal
git-subtree-mainline: d95165fc8f
git-subtree-split: 102ba84500

fiscal/central/app/rate_limit.py

@@ -0,0 +1,36 @@
+"""In-memory per-IP rate limiting for pre-authentication routes.
+
+Same spirit as painel-clientes-web's `app/rate_limit.py`: a single-process
+in-memory counter, fine because the Hub runs as one container behind a
+trusted reverse proxy (FORWARDED_ALLOW_IPS), never multiple replicas behind
+a shared load balancer. A process restart resets the history — accepted,
+same tradeoff as that panel's SESSION_SECRET.
+
+Used for the two public, pre-authentication Agent-distribution routes
+(GET /dl/agent/{token}, POST /v1/agents/enroll): invalid attempts count
+against the caller's IP; a legitimate Agent's own successful traffic never
+gets counted, so it can never push other installations over the limit.
+"""
+import time
+
+MAX_ATTEMPTS = 10
+WINDOW_SECONDS = 5 * 60
+
+_attempts: dict[tuple[str, str], list[float]] = {}
+
+
+def _recent(bucket: str, origin: str, now: float) -> list[float]:
+    cutoff = now - WINDOW_SECONDS
+    return [t for t in _attempts.get((bucket, origin), []) if t > cutoff]
+
+
+def blocked(bucket: str, origin: str, now: float | None = None) -> bool:
+    moment = now if now is not None else time.time()
+    return len(_recent(bucket, origin, moment)) >= MAX_ATTEMPTS
+
+
+def record_attempt(bucket: str, origin: str, now: float | None = None) -> None:
+    moment = now if now is not None else time.time()
+    recent = _recent(bucket, origin, moment)
+    recent.append(moment)
+    _attempts[(bucket, origin)] = recent