fix(collector/bridge/gateway): rate limit 구조적 수정 — 점진적 백오프 + adaptive 폴링 + burst-friendly 윈도우

bridge.py

@@ -176,8 +176,9 @@ class RemoteTransport(BridgeTransport):
         # Rate limit backoff
         self._rate_limited_until = 0.0  # timestamp until which we should not send requests
         self._backoff_seconds = 0.0  # current backoff duration (exponential)
-        self._BACKOFF_BASE = 1.0
+        self._BACKOFF_BASE = 2.0
         self._BACKOFF_MAX = 60.0
+        self._success_streak = 0  # consecutive successes for gradual backoff reduction
 
         # Retry queue: list of (method, path, data) tuples
         self._retry_queue: list[tuple[str, str, dict | None]] = []
@@ -207,6 +208,7 @@ class RemoteTransport(BridgeTransport):
 
     def _apply_backoff(self, retry_after: float = 0):
         """Apply exponential backoff for rate limiting."""
+        self._success_streak = 0  # Reset success streak on any failure
         if retry_after > 0:
             self._backoff_seconds = min(retry_after, self._BACKOFF_MAX)
         else:
@@ -217,11 +219,22 @@ class RemoteTransport(BridgeTransport):
         self._rate_limited_until = time.time() + self._backoff_seconds
         logger.warning(f"RemoteTransport: backing off {self._backoff_seconds:.0f}s (until +{self._backoff_seconds:.0f}s)")
 
-    def _reset_backoff(self):
-        """Reset backoff after a successful request."""
-        if self._backoff_seconds > 0:
-            self._backoff_seconds = 0
-            self._rate_limited_until = 0
+    def _on_request_success(self):
+        """Gradually reduce backoff after consecutive successes.
+
+        Instead of instantly resetting to 0 (which causes the 1s oscillation loop
+        when 7 loops share one transport), require sustained success before reducing.
+        """
+        if self._backoff_seconds <= 0:
+            return  # Already at zero, nothing to do
+        self._success_streak += 1
+        if self._success_streak >= 5:
+            # Halve the backoff (gradual cooldown)
+            self._backoff_seconds = self._backoff_seconds / 2
+            if self._backoff_seconds < 0.5:
+                self._backoff_seconds = 0
+                self._rate_limited_until = 0
+            self._success_streak = 0
 
     async def _arequest(self, method: str, path: str, data: dict | None = None) -> dict | None:
         """Async non-blocking HTTP request to Gateway API."""
@@ -250,7 +263,7 @@ class RemoteTransport(BridgeTransport):
                     logger.info("RemoteTransport: ✅ Gateway connected")
                 self.connected = True
                 self._consecutive_failures = 0
-                self._reset_backoff()
+                self._on_request_success()
                 return result
         except Exception as e:
             self._consecutive_failures += 1