During handling of the above exception, another exception occurred

字面意思为：在处理上述异常的过程中，发生了另一个异常。简单理解就是，程序执行——>异常——>异常处理——>又引发异常——>又异常处理…此时，在报错信息之间就会出现上面一行英文。

代码示例

# -*- coding:utf-8 -*-
# date:
# info: during_handling.py
# Python 3.8.8

import requests


class DuringHandle(object):
    def __init__(self):
        self.HEADERS = {
            'Accept': 'application/json, text/javascript, */*; q=0.01',
            'Accept-Encoding': 'gzip, deflate, br',
            'Accept-Language': 'zh-CN,zh;q=0.9',
            'Connection': 'keep-alive',
            'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.88 Safari/537.36',
            'X-Requested-With': 'XMLHttpRequest',
        }
        self.code = 'Nhf876Y8mk1sdi2lf'
        self.RS = requests.Session()

    def get_session_id(self):
        u = 'https://cm.lanjing.com/account/sso/?next=/asset/server/list&code={}'.format(self.code)
        req = self.RS.get(url=u, headers=self.HEADERS)
        return req.cookies['sessionid']

    def main_run(self):
        session_id = self.get_session_id()
        print(session_id)


if __name__ == '__main__':
    dh = DuringHandle()
    dh.main_run()

运行代码

由于 req = self.RS.get(url=u, headers=self.HEADERS) 缺少参数 verify=False ，在执行上述代码，抛出如下异常

Traceback (most recent call last):
  File "E:\pythonProject\proCmp\venv\lib\site-packages\urllib3\connectionpool.py", line 670, in urlopen
    httplib_response = self._make_request(
  File "E:\pythonProject\proCmp\venv\lib\site-packages\urllib3\connectionpool.py", line 381, in _make_request
    self._validate_conn(conn)
  File "E:\pythonProject\proCmp\venv\lib\site-packages\urllib3\connectionpool.py", line 978, in _validate_conn
    conn.connect()
  File "E:\pythonProject\proCmp\venv\lib\site-packages\urllib3\connection.py", line 362, in connect
    self.sock = ssl_wrap_socket(
  File "E:\pythonProject\proCmp\venv\lib\site-packages\urllib3\util\ssl_.py", line 386, in ssl_wrap_socket
    return context.wrap_socket(sock, server_hostname=server_hostname)
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python38\lib\ssl.py", line 500, in wrap_socket
    return self.sslsocket_class._create(
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python38\lib\ssl.py", line 1040, in _create
    self.do_handshake()
  File "C:\Users\Administrator\AppData\Local\Programs\Python\Python38\lib\ssl.py", line 1309, in do_handshake
    self._sslobj.do_handshake()
ssl.SSLCertVerificationError: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: certificate has expired (_ssl.c:1125)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "E:\pythonProject\proCmp\venv\lib\site-packages\requests\adapters.py", line 439, in send
    resp = conn.urlopen(
  File "E:\pythonProject\proCmp\venv\lib\site-packages\urllib3\connectionpool.py", line 726, in urlopen
    retries = retries.increment(
  File "E:\pythonProject\proCmp\venv\lib\site-packages\urllib3\util\retry.py", line 446, in increment
    raise MaxRetryError(_pool, url, error or ResponseError(cause))
urllib3.exceptions.MaxRetryError: HTTPSConnectionPool(host='cm.lanjing.com', port=443): Max retries exceeded with url: /account/sso/?next=/asset/server/list&code=Nhf876Y8mk1sdi2lf (Caused by SSLError(SSLCertVerificationError(1, '[SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: certificate has expired (_ssl.c:1125)')))

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "E:/pythonProject/proCmp/py_script/during_handling.py", line 215, in <module>
    dh.main_run()
  File "E:/pythonProject/proCmp/py_script/during_handling.py", line 162, in main_run
    session_id = self.get_session_id()
  File "E:/pythonProject/proCmp/py_script/during_handling.py", line 65, in get_session_id
    req = self.RS.get(url=u, headers=self.HEADERS)
  File "E:\pythonProject\proCmp\venv\lib\site-packages\requests\sessions.py", line 543, in get
    return self.request('GET', url, **kwargs)
  File "E:\pythonProject\proCmp\venv\lib\site-packages\requests\sessions.py", line 530, in request
    resp = self.send(prep, **send_kwargs)
  File "E:\pythonProject\proCmp\venv\lib\site-packages\requests\sessions.py", line 643, in send
    r = adapter.send(request, **kwargs)
  File "E:\pythonProject\proCmp\venv\lib\site-packages\requests\adapters.py", line 514, in send
    raise SSLError(e, request=request)
requests.exceptions.SSLError: HTTPSConnectionPool(host='cm.lanjing.com', port=443): Max retries exceeded with url: /account/sso/?next=/asset/server/list&code=Nhf876Y8mk1sdi2lf (Caused by SSLError(SSLCertVerificationError(1, '[SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: certificate has expired (_ssl.c:1125)')))

Process finished with exit code 1

报错解读

第一个 Traceback 触发了 ssl.SSLCertVerificationError 报错，且下面出现 During handling of the above exception, another exception occurred ，继续看第二个 Traceback，触发了 urllib3.exceptions.MaxRetryError，且下面也出现了 During handling of the above exception, another exception occurred，继续看第三个 Traceback，触发了 requests.exceptions.SSLError ，且只有此处的异常是由自编程的代码导致了异常，第一、二个均是Python的库代码的异常。

尝试修改代码

# 省略部分代码
# return req.cookies['sessionid']
try:
    req = self.RS.get(url=u, headers=self.HEADERS)
    return req.cookies['sessionid']
except requests.exceptions.SSLError as e:
    print('requests.exceptions.SSLError:{}'.format(e))
    return

# 省略部分代码

运行代码

运行代码后发现，程序完整运行，自定义输出异常内容

requests.exceptions.SSLError:HTTPSConnectionPool(host='cm.lanjing.com', port=443): Max retries exceeded with url: /account/sso/?next=/asset/server/list&code=Nhf876Y8mk1sdi2lf (Caused by SSLError(SSLCertVerificationError(1, '[SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: certificate has expired (_ssl.c:1125)')))