python - NoneType' 对象没有属性 '__getitem__'

Question

我在 openstack 设置中尝试 nova-list cli 命令时遇到以下错误。NoneType' 对象没有属性 'getitem'

 DEBUG (shell:777) 'NoneType' object has no attribute '__getitem__'
    Traceback (most recent call last):
      File "/opt/stack/python-novaclient/novaclient/shell.py", line 774, in main
        OpenStackComputeShell().main(map(strutils.safe_decode, sys.argv[1:]))
      File "/opt/stack/python-novaclient/novaclient/shell.py", line 685, in main
        self.cs.authenticate()
      File "/opt/stack/python-novaclient/novaclient/v1_1/client.py", line 169, in authenticate
        self.client.authenticate()
      File "/opt/stack/python-novaclient/novaclient/client.py", line 382, in authenticate
        auth_url = self._v2_auth(auth_url)
      File "/opt/stack/python-novaclient/novaclient/client.py", line 469, in _v2_auth
        return self._authenticate(url, body)
      File "/opt/stack/python-novaclient/novaclient/client.py", line 484, in _authenticate
        return self._extract_service_catalog(url, resp, respbody)
      File "/opt/stack/python-novaclient/novaclient/client.py", line 307, in _extract_service_catalog
        self.auth_token = self.service_catalog.get_token()
      File "/opt/stack/python-novaclient/novaclient/service_catalog.py", line 29, in get_token
        return self.catalog['access']['token']['id']
    TypeError: 'NoneType' object has no attribute '__getitem__'
    ERROR: 'NoneType' object has no attribute '__getitem_

_'

这是什么意思？是我的 openstack 设置有问题还是一些 python 相关的错误？

Answer 1

从字面上看，'NoneType' object has no attribute... 表示您正在尝试访问属性或调用具有值 None 的对象的方法。

实际上，这意味着您可能在某处存在错误，即在为变量赋值之前使用变量，或者使用返回 None 的函数的值。调试此问题的第一步是问自己“为什么将此变量设置为 None？”。

在此特定情况下，self.catalog、self.catalog['access'] 或 self.catalog['access']['token '] 是 None。