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Apply patch
This commit is contained in:
William FH
parent
16b47a8c17
commit
0c5ca73d9d
@ -4,9 +4,19 @@ from __future__ import annotations
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import abc
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import asyncio
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import logging
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import random
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import threading
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import time
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from typing import Optional
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from contextlib import asynccontextmanager
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from typing import Any, Dict, Optional, Union
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# Optional Redis imports - will be None if not available
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coredis = None
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try:
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import coredis
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except ImportError:
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pass
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class BaseRateLimiter(abc.ABC):
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@ -253,7 +263,542 @@ class InMemoryRateLimiter(BaseRateLimiter):
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return True
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class RedisRateLimiter(BaseRateLimiter):
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"""A Redis-based distributed rate limiter using sliding window algorithm.
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This rate limiter provides distributed rate limiting across multiple processes,
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pods, or containers using Redis as the shared state store. It uses a sliding
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window counter algorithm implemented with Redis sorted sets and Lua scripts
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for atomic operations.
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Key features:
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- Distributed rate limiting across multiple processes/pods
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- Sliding window algorithm for accurate rate limiting
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- Atomic operations using Lua scripts
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- Connection pooling and Redis cluster support
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- Comprehensive error handling with fallback options
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- High performance with minimal Redis round trips
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Example:
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.. code-block:: python
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from langchain_core.rate_limiters import RedisRateLimiter
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# Basic usage
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rate_limiter = RedisRateLimiter(
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redis_url="redis://localhost:6379",
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requests_per_second=10,
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window_size=60, # 60 second sliding window
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)
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# With Redis cluster
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rate_limiter = RedisRateLimiter(
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redis_url="redis://node1:7000,redis://node2:7000,redis://node3:7000",
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requests_per_second=100,
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window_size=60,
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redis_cluster=True,
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)
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# Use with chat model
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from langchain_anthropic import ChatAnthropic
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model = ChatAnthropic(
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model_name="claude-3-opus-20240229",
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rate_limiter=rate_limiter
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)
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.. versionadded:: 0.2.25
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"""
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# Lua script for atomic rate limit checking and updating
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_CHECK_AND_UPDATE_SCRIPT = """
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local key = KEYS[1]
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local window_size = tonumber(ARGV[1])
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local max_requests = tonumber(ARGV[2])
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local current_time = tonumber(ARGV[3])
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local cleanup_probability = tonumber(ARGV[4])
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-- Remove expired entries (sliding window cleanup)
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local cutoff_time = current_time - window_size
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redis.call('ZREMRANGEBYSCORE', key, '-inf', cutoff_time)
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-- Count current requests in window
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local current_count = redis.call('ZCARD', key)
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-- Check if we can proceed
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if current_count < max_requests then
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-- Add current request with unique score to handle concurrent requests
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local score = current_time + math.random() * 0.001
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redis.call('ZADD', key, score, score)
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-- Set expiration for the key (window_size + buffer)
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redis.call('EXPIRE', key, window_size + 60)
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-- Probabilistic cleanup of old entries
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if math.random() < cleanup_probability then
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redis.call('ZREMRANGEBYSCORE', key, '-inf', cutoff_time - window_size)
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end
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return {1, current_count + 1, max_requests}
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else
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return {0, current_count, max_requests}
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end
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"""
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# Lua script for non-blocking rate limit check
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_CHECK_ONLY_SCRIPT = """
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local key = KEYS[1]
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local window_size = tonumber(ARGV[1])
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local max_requests = tonumber(ARGV[2])
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local current_time = tonumber(ARGV[3])
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-- Remove expired entries
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local cutoff_time = current_time - window_size
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redis.call('ZREMRANGEBYSCORE', key, '-inf', cutoff_time)
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-- Count current requests in window
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local current_count = redis.call('ZCARD', key)
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-- Return availability without consuming
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if current_count < max_requests then
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return {1, current_count, max_requests}
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else
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return {0, current_count, max_requests}
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end
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"""
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def __init__(
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self,
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*,
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redis_url: str = "redis://localhost:6379",
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requests_per_second: float = 1,
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window_size: int = 60,
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key_prefix: str = "langchain:ratelimit",
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identifier: Optional[str] = None,
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redis_cluster: bool = False,
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connection_pool_size: int = 10,
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socket_timeout: float = 5.0,
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socket_connect_timeout: float = 5.0,
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retry_on_timeout: bool = True,
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health_check_interval: int = 30,
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fallback_to_memory: bool = True,
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cleanup_probability: float = 0.1,
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check_every_n_seconds: float = 0.1,
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**redis_kwargs: Any,
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) -> None:
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"""Initialize Redis-based distributed rate limiter.
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Args:
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redis_url: Redis connection URL. For clusters, provide comma-separated URLs.
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requests_per_second: Maximum requests allowed per second.
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window_size: Sliding window size in seconds.
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key_prefix: Prefix for Redis keys to avoid collisions.
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identifier: Unique identifier for this rate limiter instance.
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If None, will be auto-generated.
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redis_cluster: Whether to use Redis cluster mode.
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connection_pool_size: Size of the Redis connection pool.
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socket_timeout: Socket timeout for Redis operations.
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socket_connect_timeout: Socket connection timeout.
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retry_on_timeout: Whether to retry on timeout errors.
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health_check_interval: Interval for Redis health checks.
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fallback_to_memory: Whether to fallback to InMemoryRateLimiter on Redis errors.
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cleanup_probability: Probability of performing cleanup on each request (0.0-1.0).
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check_every_n_seconds: Sleep interval when blocking and waiting for tokens.
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**redis_kwargs: Additional Redis client configuration.
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"""
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if coredis is None:
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raise ImportError(
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"RedisRateLimiter requires the 'coredis' package. "
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"Install it with: pip install coredis"
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)
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self.redis_url = redis_url
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self.requests_per_second = requests_per_second
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self.window_size = window_size
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self.max_requests = int(requests_per_second * window_size)
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self.key_prefix = key_prefix
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self.identifier = identifier or f"rl_{int(time.time())}_{random.randint(1000, 9999)}"
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self.redis_cluster = redis_cluster
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self.connection_pool_size = connection_pool_size
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self.socket_timeout = socket_timeout
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self.socket_connect_timeout = socket_connect_timeout
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self.retry_on_timeout = retry_on_timeout
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self.health_check_interval = health_check_interval
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self.fallback_to_memory = fallback_to_memory
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self.cleanup_probability = cleanup_probability
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self.check_every_n_seconds = check_every_n_seconds
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self.redis_kwargs = redis_kwargs
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# Redis client and connection management
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self._redis_client: Optional[Union[coredis.Redis, coredis.RedisCluster]] = None
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self._connection_lock = threading.Lock()
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self._last_health_check = 0.0
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self._redis_healthy = True
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self._circuit_breaker_failures = 0
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self._circuit_breaker_last_failure = 0.0
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self._circuit_breaker_threshold = 5
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self._circuit_breaker_timeout = 60.0
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# Fallback rate limiter
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self._fallback_limiter: Optional[InMemoryRateLimiter] = None
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if self.fallback_to_memory:
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self._fallback_limiter = InMemoryRateLimiter(
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requests_per_second=requests_per_second,
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check_every_n_seconds=check_every_n_seconds,
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max_bucket_size=max(1, requests_per_second * 2), # Allow some burst
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)
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# Lua script SHA hashes (will be populated on first use)
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self._check_and_update_sha: Optional[str] = None
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self._check_only_sha: Optional[str] = None
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# Logger
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self._logger = logging.getLogger(__name__)
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def _get_redis_key(self) -> str:
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"""Generate Redis key for this rate limiter instance."""
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return f"{self.key_prefix}:{self.identifier}"
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def _create_redis_client(self) -> Union[coredis.Redis, coredis.RedisCluster]:
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"""Create and configure Redis client."""
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common_config = {
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"socket_timeout": self.socket_timeout,
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"socket_connect_timeout": self.socket_connect_timeout,
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"retry_on_timeout": self.retry_on_timeout,
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"health_check_interval": self.health_check_interval,
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**self.redis_kwargs,
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}
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if self.redis_cluster:
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# Parse cluster URLs
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urls = [url.strip() for url in self.redis_url.split(",")]
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startup_nodes = []
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for url in urls:
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if "://" in url:
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# Parse redis://host:port format
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parts = url.split("://")[1].split(":")
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host = parts[0]
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port = int(parts[1]) if len(parts) > 1 else 6379
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else:
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# Parse host:port format
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parts = url.split(":")
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host = parts[0]
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port = int(parts[1]) if len(parts) > 1 else 6379
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startup_nodes.append({"host": host, "port": port})
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return coredis.RedisCluster(
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startup_nodes=startup_nodes,
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**common_config,
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)
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else:
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return coredis.Redis.from_url(
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self.redis_url,
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max_connections=self.connection_pool_size,
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**common_config,
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)
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def _get_redis_client(self) -> Union[coredis.Redis, coredis.RedisCluster]:
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"""Get Redis client with connection management and health checking."""
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current_time = time.time()
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# Check circuit breaker
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if (self._circuit_breaker_failures >= self._circuit_breaker_threshold and
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current_time - self._circuit_breaker_last_failure < self._circuit_breaker_timeout):
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raise ConnectionError("Circuit breaker is open - Redis unavailable")
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with self._connection_lock:
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# Create client if needed
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if self._redis_client is None:
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self._redis_client = self._create_redis_client()
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# Periodic health check
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if current_time - self._last_health_check > self.health_check_interval:
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try:
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# Simple ping to check health
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asyncio.create_task(self._redis_client.ping())
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self._redis_healthy = True
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self._circuit_breaker_failures = 0
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self._last_health_check = current_time
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except Exception as e:
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self._logger.warning(f"Redis health check failed: {e}")
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self._redis_healthy = False
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self._circuit_breaker_failures += 1
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self._circuit_breaker_last_failure = current_time
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# Recreate client on health check failure
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try:
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if hasattr(self._redis_client, 'close'):
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asyncio.create_task(self._redis_client.close())
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except Exception:
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pass
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self._redis_client = None
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raise ConnectionError(f"Redis health check failed: {e}")
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return self._redis_client
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async def _ensure_scripts_loaded(self, redis_client: Union[coredis.Redis, coredis.RedisCluster]) -> None:
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"""Ensure Lua scripts are loaded into Redis."""
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try:
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if self._check_and_update_sha is None:
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self._check_and_update_sha = await redis_client.script_load(self._CHECK_AND_UPDATE_SCRIPT)
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if self._check_only_sha is None:
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self._check_only_sha = await redis_client.script_load(self._CHECK_ONLY_SCRIPT)
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except Exception as e:
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self._logger.warning(f"Failed to load Lua scripts: {e}")
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# Reset SHAs to force reload on next attempt
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self._check_and_update_sha = None
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self._check_only_sha = None
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raise
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async def _execute_rate_limit_check(
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self,
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redis_client: Union[coredis.Redis, coredis.RedisCluster],
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consume_token: bool = True
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) -> tuple[bool, int, int]:
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"""Execute rate limit check using Lua script.
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Returns:
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Tuple of (allowed, current_count, max_requests)
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"""
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await self._ensure_scripts_loaded(redis_client)
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key = self._get_redis_key()
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current_time = time.time()
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try:
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if consume_token:
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result = await redis_client.evalsha(
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self._check_and_update_sha,
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1, # number of keys
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key,
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str(self.window_size),
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str(self.max_requests),
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str(current_time),
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str(self.cleanup_probability),
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)
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else:
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result = await redis_client.evalsha(
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self._check_only_sha,
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1, # number of keys
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key,
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str(self.window_size),
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str(self.max_requests),
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str(current_time),
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)
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allowed, current_count, max_requests = result
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return bool(allowed), int(current_count), int(max_requests)
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except Exception as e:
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# If script execution fails, try to reload and retry once
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self._logger.warning(f"Lua script execution failed, reloading: {e}")
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self._check_and_update_sha = None
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self._check_only_sha = None
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await self._ensure_scripts_loaded(redis_client)
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if consume_token:
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result = await redis_client.evalsha(
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self._check_and_update_sha,
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1,
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key,
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str(self.window_size),
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str(self.max_requests),
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str(current_time),
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str(self.cleanup_probability),
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)
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else:
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result = await redis_client.evalsha(
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self._check_only_sha,
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1,
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key,
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str(self.window_size),
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str(self.max_requests),
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str(current_time),
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)
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allowed, current_count, max_requests = result
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return bool(allowed), int(current_count), int(max_requests)
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def _should_use_fallback(self, error: Exception) -> bool:
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"""Determine if we should use fallback rate limiter based on error type."""
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if not self.fallback_to_memory or self._fallback_limiter is None:
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return False
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# Use fallback for connection errors, timeouts, and Redis unavailability
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return isinstance(error, (
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ConnectionError,
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TimeoutError,
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OSError, # Network errors
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)) or "connection" in str(error).lower()
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def acquire(self, *, blocking: bool = True) -> bool:
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"""Attempt to acquire a token from the rate limiter.
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Args:
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blocking: If True, block until token is available.
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If False, return immediately with result.
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Returns:
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True if token was acquired, False otherwise.
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"""
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# Run async method in sync context
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try:
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loop = asyncio.get_event_loop()
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if loop.is_running():
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# We're in an async context, create a new event loop in a thread
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import concurrent.futures
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with concurrent.futures.ThreadPoolExecutor() as executor:
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future = executor.submit(
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lambda: asyncio.run(self.aacquire(blocking=blocking))
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)
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return future.result()
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else:
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return loop.run_until_complete(self.aacquire(blocking=blocking))
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except RuntimeError:
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# No event loop, create one
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return asyncio.run(self.aacquire(blocking=blocking))
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async def aacquire(self, *, blocking: bool = True) -> bool:
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"""Attempt to acquire a token from the rate limiter. Async version.
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Args:
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blocking: If True, block until token is available.
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If False, return immediately with result.
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Returns:
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True if token was acquired, False otherwise.
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"""
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max_retries = 3
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retry_delay = 0.1
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for attempt in range(max_retries):
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try:
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redis_client = self._get_redis_client()
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if not blocking:
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# Non-blocking: just check availability
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allowed, current_count, max_requests = await self._execute_rate_limit_check(
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redis_client, consume_token=False
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)
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if allowed:
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# If available, consume the token
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allowed, _, _ = await self._execute_rate_limit_check(
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redis_client, consume_token=True
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)
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return allowed
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else:
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# Blocking: keep trying until we get a token
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while True:
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allowed, current_count, max_requests = await self._execute_rate_limit_check(
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redis_client, consume_token=True
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)
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if allowed:
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return True
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# Wait before retrying
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await asyncio.sleep(self.check_every_n_seconds)
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except Exception as e:
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self._logger.warning(f"Redis rate limiter error (attempt {attempt + 1}): {e}")
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# Update circuit breaker
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self._circuit_breaker_failures += 1
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self._circuit_breaker_last_failure = time.time()
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if self._should_use_fallback(e):
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self._logger.info("Falling back to in-memory rate limiter")
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return await self._fallback_limiter.aacquire(blocking=blocking)
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if attempt < max_retries - 1:
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await asyncio.sleep(retry_delay * (2 ** attempt)) # Exponential backoff
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else:
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# Final attempt failed
|
||||
if self.fallback_to_memory and self._fallback_limiter:
|
||||
self._logger.error(f"All Redis attempts failed, using fallback: {e}")
|
||||
return await self._fallback_limiter.aacquire(blocking=blocking)
|
||||
else:
|
||||
raise ConnectionError(f"Redis rate limiter unavailable: {e}")
|
||||
|
||||
# Should not reach here, but just in case
|
||||
if self.fallback_to_memory and self._fallback_limiter:
|
||||
return await self._fallback_limiter.aacquire(blocking=blocking)
|
||||
return False
|
||||
|
||||
async def get_current_usage(self) -> Dict[str, Union[int, float]]:
|
||||
"""Get current rate limiter usage statistics.
|
||||
|
||||
Returns:
|
||||
Dictionary with usage statistics including current count,
|
||||
max requests, and utilization percentage.
|
||||
"""
|
||||
try:
|
||||
redis_client = self._get_redis_client()
|
||||
allowed, current_count, max_requests = await self._execute_rate_limit_check(
|
||||
redis_client, consume_token=False
|
||||
)
|
||||
|
||||
utilization = (current_count / max_requests) * 100 if max_requests > 0 else 0
|
||||
|
||||
return {
|
||||
"current_count": current_count,
|
||||
"max_requests": max_requests,
|
||||
"utilization_percent": utilization,
|
||||
"requests_per_second": self.requests_per_second,
|
||||
"window_size": self.window_size,
|
||||
"redis_healthy": self._redis_healthy,
|
||||
}
|
||||
except Exception as e:
|
||||
self._logger.warning(f"Failed to get usage statistics: {e}")
|
||||
return {
|
||||
"current_count": -1,
|
||||
"max_requests": self.max_requests,
|
||||
"utilization_percent": -1,
|
||||
"requests_per_second": self.requests_per_second,
|
||||
"window_size": self.window_size,
|
||||
"redis_healthy": False,
|
||||
"error": str(e),
|
||||
}
|
||||
|
||||
async def reset(self) -> bool:
|
||||
"""Reset the rate limiter by clearing all stored data.
|
||||
|
||||
Returns:
|
||||
True if reset was successful, False otherwise.
|
||||
"""
|
||||
try:
|
||||
redis_client = self._get_redis_client()
|
||||
key = self._get_redis_key()
|
||||
await redis_client.delete(key)
|
||||
self._logger.info(f"Rate limiter reset for key: {key}")
|
||||
return True
|
||||
except Exception as e:
|
||||
self._logger.error(f"Failed to reset rate limiter: {e}")
|
||||
return False
|
||||
|
||||
async def close(self) -> None:
|
||||
"""Close Redis connections and cleanup resources."""
|
||||
if self._redis_client:
|
||||
try:
|
||||
if hasattr(self._redis_client, 'close'):
|
||||
await self._redis_client.close()
|
||||
except Exception as e:
|
||||
self._logger.warning(f"Error closing Redis client: {e}")
|
||||
finally:
|
||||
self._redis_client = None
|
||||
|
||||
def __del__(self) -> None:
|
||||
"""Cleanup on object destruction."""
|
||||
if self._redis_client:
|
||||
try:
|
||||
asyncio.create_task(self.close())
|
||||
except Exception:
|
||||
pass
|
||||
|
||||
|
||||
__all__ = [
|
||||
"BaseRateLimiter",
|
||||
"InMemoryRateLimiter",
|
||||
"RedisRateLimiter",
|
||||
]
|
||||
|
||||
|
||||
Loading…
Reference in New Issue
Block a user