110 lines
3.3 KiB
Python
110 lines
3.3 KiB
Python
"""LLM 调用全局限速器（令牌桶算法）
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所有 LLMProvider 实例共享同一个 RateLimiter 单例，
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确保跨 Provider 的总调用频率不超过配置上限。
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"""
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import asyncio
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import logging
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import os
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import time
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from collections import deque
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logger = logging.getLogger(__name__)
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class TokenBucketRateLimiter:
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"""基于令牌桶算法的速率限制器
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默认 30 RPM（每秒补充约 0.5 个令牌），可通过环境变量
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LLM_RATE_LIMIT_RPM 调整。
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"""
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_instance: "TokenBucketRateLimiter | None" = None
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_lock = asyncio.Lock()
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def __init__(
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self,
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max_rpm: float = 30.0,
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):
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self._max_rpm = max_rpm
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self._refill_rate = max_rpm / 60.0 # tokens per second
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self._max_tokens = max_rpm
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self._tokens = max_rpm # start full
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self._last_refill = time.monotonic()
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self._semaphore = asyncio.Semaphore(1) # 一次只能有一个 acquire 等待
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# 用于记录最近请求时间（调试/监控用）
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self._recent_requests: deque[float] = deque(maxlen=int(max_rpm * 2))
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@classmethod
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def get_instance(cls) -> "TokenBucketRateLimiter":
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"""获取全局单例"""
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if cls._instance is None:
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rpm = float(os.getenv("LLM_RATE_LIMIT_RPM", "30"))
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cls._instance = cls(max_rpm=rpm)
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logger.info(f"LLM RateLimiter initialized: {rpm} RPM")
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return cls._instance
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@classmethod
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async def reset_instance(cls) -> None:
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"""重置单例（仅用于测试）"""
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async with cls._lock:
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if cls._instance is not None:
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cls._instance = None
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def _refill(self) -> None:
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"""补充令牌"""
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now = time.monotonic()
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elapsed = now - self._last_refill
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tokens_to_add = elapsed * self._refill_rate
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self._tokens = min(self._max_tokens, self._tokens + tokens_to_add)
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self._last_refill = now
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async def acquire(self) -> None:
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"""获取一个令牌，若无可用令牌则等待
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此方法可安全地从多个协程并发调用。
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"""
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async with self._semaphore:
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self._refill()
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if self._tokens >= 1.0:
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self._tokens -= 1.0
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self._recent_requests.append(time.monotonic())
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return
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# 如果没有可用令牌，计算等待时间
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wait_time = (1.0 - self._tokens) / self._refill_rate
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if wait_time > 0:
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logger.debug(f"LLM rate limiter: waiting {wait_time:.2f}s for token")
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await asyncio.sleep(wait_time)
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# 重试获取
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async with self._semaphore:
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self._refill()
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self._tokens = max(0.0, self._tokens - 1.0)
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self._recent_requests.append(time.monotonic())
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@property
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def available_tokens(self) -> float:
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"""当前可用令牌数"""
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return self._tokens
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@property
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def max_rpm(self) -> float:
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"""配置的最大 RPM"""
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return self._max_rpm
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# 模块级便捷函数
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_rate_limiter: TokenBucketRateLimiter | None = None
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def get_rate_limiter() -> TokenBucketRateLimiter:
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"""获取全局速率限制器实例"""
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return TokenBucketRateLimiter.get_instance()
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# 别名以支持测试验收标准
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RateLimiter = TokenBucketRateLimiter
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