Kris
15fc62d478
- 新增六层UI自动化架构：从Backend到Capabilities的完整分层实现 - 添加WeChat 4.0分辨率适配Profile与图像模板资源 - 实现幂等缓存、熔断器、重试策略、链路追踪与监控指标 - 新增头像下载安全校验、发布朋友圈路径白名单防护 - 优化密钥缓存、DB校验逻辑与初始化流程 - 补充完整错误码体系与启动清场机制
129 lines
4.1 KiB
Python
129 lines
4.1 KiB
Python
"""通用熔断器：保护下游资源免受连续失败冲击。
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状态机：
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CLOSED → 连续失败达 failure_threshold → OPEN
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OPEN → 经过 recovery_timeout → HALF_OPEN
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HALF_OPEN → 一次成功 → CLOSED / 一次失败 → OPEN
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供 FlowOrchestrator 对 DB 校验失败、WeChat 启动失败等做熔断保护。
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"""
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from __future__ import annotations
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import enum
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import logging
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import time
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import threading
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logger = logging.getLogger("woc-bridge")
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class CircuitState(enum.Enum):
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"""熔断器状态。"""
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CLOSED = "closed" # 正常工作，请求通过
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OPEN = "open" # 熔断中，请求拒绝
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HALF_OPEN = "half_open" # 半开，允许一次试探请求
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class CircuitBreaker:
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"""熔断器。
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Attributes:
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name: 熔断器名称（如 "db_verify"）
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failure_threshold: 连续失败次数阈值，默认 5
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recovery_timeout: 熔断恢复秒数，默认 30
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"""
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def __init__(
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self,
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name: str,
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failure_threshold: int = 5,
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recovery_timeout: float = 30.0,
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) -> None:
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"""初始化熔断器。
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Args:
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name: 熔断器名称
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failure_threshold: 连续失败次数阈值
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recovery_timeout: 熔断恢复秒数
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"""
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self.name = name
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self.failure_threshold = failure_threshold
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self.recovery_timeout = recovery_timeout
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self._state = CircuitState.CLOSED
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self._fail_count = 0
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self._last_failure_time: float = 0.0
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self._lock = threading.Lock()
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@property
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def state(self) -> CircuitState:
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"""当前状态。
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OPEN 状态超过 recovery_timeout 自动转 HALF_OPEN。
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"""
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with self._lock:
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if (
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self._state == CircuitState.OPEN
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and time.monotonic() - self._last_failure_time >= self.recovery_timeout
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):
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self._state = CircuitState.HALF_OPEN
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logger.info(
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"[breaker:%s] OPEN -> HALF_OPEN (after %.0fs)",
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self.name, self.recovery_timeout,
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)
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return self._state
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def allow(self) -> bool:
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"""是否允许请求通过。
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CLOSED / HALF_OPEN 允许；OPEN 拒绝。
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HALF_OPEN 时只允许一次试探（调用方需配合 record_success/failure）。
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"""
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return self.state in (CircuitState.CLOSED, CircuitState.HALF_OPEN)
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def record_success(self) -> None:
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"""记录一次成功。
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CLOSED: 重置失败计数。
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HALF_OPEN: 转 CLOSED，恢复服务。
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"""
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with self._lock:
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if self._state == CircuitState.HALF_OPEN:
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self._state = CircuitState.CLOSED
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logger.info("[breaker:%s] HALF_OPEN -> CLOSED", self.name)
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self._fail_count = 0
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def record_failure(self) -> None:
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"""记录一次失败。
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CLOSED: 失败计数 +1，达阈值转 OPEN。
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HALF_OPEN: 立即转 OPEN。
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OPEN: 更新 last_failure_time（延长熔断）。
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"""
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with self._lock:
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self._last_failure_time = time.monotonic()
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if self._state == CircuitState.HALF_OPEN:
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self._state = CircuitState.OPEN
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logger.warning(
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"[breaker:%s] HALF_OPEN -> OPEN (probe failed)", self.name
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)
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return
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self._fail_count += 1
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if (
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self._state == CircuitState.CLOSED
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and self._fail_count >= self.failure_threshold
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):
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self._state = CircuitState.OPEN
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logger.warning(
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"[breaker:%s] CLOSED -> OPEN (fail_count=%d)",
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self.name, self._fail_count,
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)
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def reset(self) -> None:
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"""手动重置熔断器到 CLOSED 状态。"""
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with self._lock:
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self._state = CircuitState.CLOSED
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self._fail_count = 0
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self._last_failure_time = 0.0
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logger.info("[breaker:%s] reset to CLOSED", self.name)
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