Circuit Breaker Pattern in Python for LLM API Calls

import time

class CircuitBreaker:
    def __init__(self, failure_threshold=3, recovery_timeout=5):
        self.failure_threshold = failure_threshold
        self.recovery_timeout = recovery_timeout
        self.failure_count = 0
        self.state = "closed"
        self.last_failure_time = None

    def call(self, func):
        if self.state == "open":
            if time.time() - self.last_failure_time >= self.recovery_timeout:
                self.state = "half-open"
            else:
                raise RuntimeError("Circuit breaker is OPEN")
        try:
            result = func()
            if self.state == "half-open":
                self.state = "closed"
                self.failure_count = 0
            return result
        except Exception:
            self.failure_count += 1
            if self.failure_count >= self.failure_threshold or self.state == "half-open":
                self.state = "open"
                self.last_failure_time = time.time()
            raise


def mock_llm_call():
    if getattr(mock_llm_call, "attempt", 0) < 3:
        mock_llm_call.attempt = mock_llm_call.attempt + 1
        raise ConnectionError("LLM temporarily unavailable")
    return {"response": "Hello from LLM"}

mock_llm_call.attempt = 0

if __name__ == "__main__":
    breaker = CircuitBreaker(failure_threshold=2, recovery_timeout=2)
    for i in range(6):
        try:
            result = breaker.call(mock_llm_call)
            print(f"Call {i+1}: SUCCESS -> {result}")
        except Exception as e:
            print(f"Call {i+1}: FAILED -> {type(e).__name__}: {e}")
        time.sleep(0.5)