Python异步请求中无法优雅捕获Timeout Exception问题求助

问题场景 #

编写的aiohttp请求代码如下：

async with session.get(endpoint, timeout=10) as response:
        if response.status != 200:
            return self.result(endpoint, response.status)  

except aiohttp.ServerTimeoutError:
    settings.log.info(f"Host  {endpoint} is unreachable")
    return self.result(endpoint, -1)        
except TimeoutError:
    json = {"status": "unhealthy"}
    settings.log.info(f"Host  {endpoint} has timed out")
    return self.result(endpoint, -1)
except aiohttp.client_exceptions.ClientConnectorError:
    json = { "status": "unhealthy"}
    settings.log.info(f"Host  {endpoint} has timed out")
    return self.result(endpoint, -1)

请求不可达的endpoint时，抛出asyncio.exceptions.TimeoutError异常，程序意外退出，无法返回预期的unhealthy状态。

问题根源 #

1. 语法错误：缺少try关键字，except块无法和async with代码块关联，导致异常未被捕获直接抛出。
2. 异常捕获不精准：捕获的TimeoutError不是asyncio模块抛出的对应异常，导致超时异常漏捕。

修复后的代码 #

import asyncio
import aiohttp

async def check_health(session, endpoint):
    try:
        async with session.get(endpoint, timeout=10) as response:
            if response.status != 200:
                return self.result(endpoint, response.status)
    except aiohttp.ServerTimeoutError:
        settings.log.info(f"Host {endpoint} is unreachable")
        return self.result(endpoint, -1)        
    except asyncio.exceptions.TimeoutError:
        settings.log.info(f"Host {endpoint} has timed out")
        return self.result(endpoint, -1)
    except aiohttp.client_exceptions.ClientConnectorError:
        settings.log.info(f"Host {endpoint} connection failed")
        return self.result(endpoint, -1)

关键修复点 #

• 用try块包裹async with请求代码，确保except能捕获到代码块内抛出的所有异常。
• 明确捕获asyncio.exceptions.TimeoutError，精准匹配aiohttp请求超时抛出的异常类型。
• 调整日志信息，让不同异常的描述更准确（比如ClientConnectorError对应连接失败而非超时）。

内容的提问来源于stack exchange，提问作者witty_minds