84 lines
2.6 KiB
Python
84 lines
2.6 KiB
Python
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"""重试策略：指数退避 + ±25% 抖动，最多重试 1 次。
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只对 RETRYABLE_CODES 中的错误码重试，避免对永久错误做无意义重试。
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退避公式：base_delay * (2 ** attempt) * jitter
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- attempt=0: base_delay * 1 * jitter（首次重试前等待）
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- attempt=1: base_delay * 2 * jitter
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jitter 在 [0.75, 1.25] 区间均匀分布，避免雷同请求同时重试。
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"""
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from __future__ import annotations
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import logging
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import random
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from woc_bridge.ui.errors import RETRYABLE_CODES, is_retryable
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logger = logging.getLogger("woc-bridge")
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class RetryPolicy:
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"""重试策略。
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Attributes:
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max_attempts: 最大尝试次数（含首次），默认 2（即最多重试 1 次）
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base_delay: 基础退避秒数，默认 1.0
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max_delay: 最大退避秒数，默认 30.0
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"""
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def __init__(
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self,
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max_attempts: int = 2,
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base_delay: float = 1.0,
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max_delay: float = 30.0,
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) -> None:
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"""初始化重试策略。
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Args:
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max_attempts: 最大尝试次数（含首次），>=1
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base_delay: 基础退避秒数
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max_delay: 最大退避秒数（退避不会超过此值）
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"""
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if max_attempts < 1:
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raise ValueError("max_attempts must be >= 1")
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self.max_attempts = max_attempts
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self.base_delay = base_delay
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self.max_delay = max_delay
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def should_retry(self, error_code: str, attempt: int) -> bool:
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"""是否应该重试。
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条件：attempt < max_attempts - 1 AND error_code in RETRYABLE_CODES。
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attempt 为重试序号（0 表示首次失败后考虑第一次重试）；
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max_attempts 含首次尝试，故允许的重试次数为 max_attempts - 1。
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Args:
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error_code: 错误码（如 SEND_TIMEOUT / WINDOW_NOT_FOUND）
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attempt: 当前已尝试次数（0 表示首次失败，考虑第一次重试）
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Returns:
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True 表示应重试
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"""
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if attempt >= self.max_attempts - 1:
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return False
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return is_retryable(error_code)
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def get_delay(self, attempt: int) -> float:
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"""计算退避秒数。
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指数退避：base_delay * (2 ** attempt)
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抖动：× [0.75, 1.25] 均匀分布
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上限：max_delay
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Args:
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attempt: 当前已尝试次数（0 表示首次失败后的第一次重试前等待）
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Returns:
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退避秒数
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"""
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exponential = self.base_delay * (2 ** attempt)
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jitter = random.uniform(0.75, 1.25)
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delay = min(exponential * jitter, self.max_delay)
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return delay
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