支持gimini格式，优化debug日志

utils/usage_tracker.py

@@ -0,0 +1,72 @@
+"""用量统计 — 内存聚合
+
+按模型名聚合请求数、token 用量等统计数据。
+重启后重置，适合轻量监控场景。
+"""
+
+from __future__ import annotations
+
+import threading
+import time
+from typing import Any
+
+
+class _ModelStats:
+    __slots__ = ('request_count', 'input_tokens', 'output_tokens', 'first_seen', 'last_seen')
+
+    def __init__(self):
+        self.request_count = 0
+        self.input_tokens = 0
+        self.output_tokens = 0
+        self.first_seen = time.time()
+        self.last_seen = time.time()
+
+
+class UsageTracker:
+    def __init__(self):
+        self._lock = threading.Lock()
+        self._stats: dict[str, _ModelStats] = {}
+        self._start_time = time.time()
+
+    def record(
+        self,
+        model: str,
+        usage: dict[str, Any] | None = None,
+        *,
+        input_key: str = 'prompt_tokens',
+        output_key: str = 'completion_tokens',
+    ) -> None:
+        """记录一次请求的用量。"""
+        with self._lock:
+            if model not in self._stats:
+                self._stats[model] = _ModelStats()
+            s = self._stats[model]
+            s.request_count += 1
+            s.last_seen = time.time()
+            if usage:
+                s.input_tokens += usage.get(input_key, 0) or 0
+                s.output_tokens += usage.get(output_key, 0) or 0
+
+    def get_stats(self) -> dict[str, Any]:
+        """返回所有模型的聚合统计。"""
+        with self._lock:
+            result = {}
+            for model, s in self._stats.items():
+                result[model] = {
+                    'request_count': s.request_count,
+                    'input_tokens': s.input_tokens,
+                    'output_tokens': s.output_tokens,
+                    'total_tokens': s.input_tokens + s.output_tokens,
+                }
+            return {
+                'uptime_seconds': int(time.time() - self._start_time),
+                'models': result,
+            }
+
+    def reset(self) -> None:
+        with self._lock:
+            self._stats.clear()
+            self._start_time = time.time()
+
+
+usage_tracker = UsageTracker()