[3.1-3.5] FAM-Edge 全链路 - API-Gateway/Video-Preprocessor/AI-Orchestrator/模型适配器(基类+Ollama+Gemini)/熔断器/JSON解析容错 + 配置

fam-edge/src/fam_edge/model_adapters/circuit_breaker.py

@@ -0,0 +1,47 @@
+"""
+熔断器 - 每个云端模型独立实例
+
+状态机: CLOSED -> OPEN -> HALF_OPEN -> CLOSED/OPEN
+- 连续 threshold 次失败 -> OPEN
+- 冷却 cooldown 秒后 -> HALF_OPEN（允许一次探测）
+- 探测成功 -> CLOSED；探测失败 -> 重新 OPEN
+"""
+from collections import deque
+import time
+
+
+class CircuitBreaker:
+    def __init__(self, threshold: int = 5, cooldown: int = 900, enabled: bool = True):
+        self.enabled = enabled
+        if enabled:
+            self.failures = deque(maxlen=threshold)
+        else:
+            self.failures = None
+        self.threshold = threshold
+        self.cooldown = cooldown
+        self.state = 'CLOSED'
+        self.last_failure = None
+
+    def record_failure(self):
+        if not self.enabled:
+            return
+        self.failures.append(time.time())
+        if len(self.failures) >= self.threshold:
+            self.state = 'OPEN'
+            self.last_failure = time.time()
+
+    def record_success(self):
+        if not self.enabled:
+            return
+        self.failures.clear()
+        self.state = 'CLOSED'
+
+    def is_open(self):
+        if not self.enabled:
+            return False
+        if self.state == 'OPEN' and self.last_failure and time.time() - self.last_failure > self.cooldown:
+            self.state = 'HALF_OPEN'
+        return self.state == 'OPEN'
+
+    def __repr__(self):
+        return f"CircuitBreaker(state={self.state}, enabled={self.enabled})"