FastAPI でフェイルオーバーとリクエストの再試行を実装する方法

from fastapi import FastAPI
import requests

app = FastAPI()

@app.get("/retry")
def retry():
    url = "http://example.com/api"  # 要请求的URL
    max_retries = 3  # 最大重试次数
    retry_interval = 1  # 重试间隔时间（秒）

    retries = 0
    while retries <= max_retries:
        try:
            response = requests.get(url)
            return response.json()
        except requests.exceptions.RequestException as error:
            print(f"Request failed: {error}")
            retries += 1
            time.sleep(retry_interval)

    return {"message": "Max retries exceeded"}

@app.get("/circuit-breaker")
def circuit_breaker():
    url = "http://example.com/api"  # 要请求的URL
    breaker = Breaker(url, max_failures=3, reset_timeout=10)

    try:
        response = breaker.execute(requests.get)
        return response.json()
    except BreakerOpenError:
        return {"message": "Service temporarily unavailable"}

class Breaker:
    def __init__(self, url, max_failures, reset_timeout):
        self.url = url
        self.max_failures = max_failures
        self.reset_timeout = reset_timeout
        self.failures = 0
        self.last_failure = None

    def execute(self, func):
        if self.failures >= self.max_failures:
            if self.last_failure and time.time() - self.last_failure < self.reset_timeout:
                raise BreakerOpenError()
            else:
                self.reset()

        try:
            response = func(self.url)
            self.failures = 0
            return response
        except requests.exceptions.RequestException as error:
            print(f"Request failed: {error}")
            self.failures += 1
            self.last_failure = time.time()

    def reset(self):
        self.failures = 0
        self.last_failure = None

class BreakerOpenError(Exception):
    pass