raise exception when an empty config file is passed to load_kube_config

[MridulS]

load_kube_config currently fails with a nondescript TypeError: 'NoneType' error if an empty kube_config file is used.

Error log

~/miniconda3/envs/dask/lib/python3.8/site-packages/kubernetes/config/kube_config.py in load_kube_config(config_file, context, client_configuration, persist_config)
    790         config_file = KUBE_CONFIG_DEFAULT_LOCATION
    791
--> 792     loader = _get_kube_config_loader(
    793         filename=config_file, active_context=context,
    794         persist_config=persist_config)

~/miniconda3/envs/dask/lib/python3.8/site-packages/kubernetes/config/kube_config.py in _get_kube_config_loader(filename, config_dict, persist_config, **kwargs)
    744         **kwargs):
    745     if config_dict is None:
--> 746         kcfg = KubeConfigMerger(filename)
    747         if persist_config and 'config_persister' not in kwargs:
    748             kwargs['config_persister'] = kcfg.save_changes

~/miniconda3/envs/dask/lib/python3.8/site-packages/kubernetes/config/kube_config.py in __init__(self, paths)
    671             self._load_config_from_file_like_object(paths)
    672         else:
--> 673             self._load_config_from_file_path(paths)
    674
    675     @property

~/miniconda3/envs/dask/lib/python3.8/site-packages/kubernetes/config/kube_config.py in _load_config_from_file_path(self, string)
    693                 if os.path.exists(path):
    694                     self.paths.append(path)
--> 695                     self.load_config(path)
    696         self.config_saved = copy.deepcopy(self.config_files)
    697

~/miniconda3/envs/dask/lib/python3.8/site-packages/kubernetes/config/kube_config.py in load_config(self, path)
    703             config_merged = copy.deepcopy(config)
    704             for item in ('clusters', 'contexts', 'users'):
--> 705                 config_merged[item] = []
    706             self.config_merged = ConfigNode(path, config_merged, path)
    707         for item in ('clusters', 'contexts', 'users'):

TypeError: 'NoneType' object does not support item assignment

I have added a check to raise a ConfigException error if an empty file is encountered.

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[MridulS]

The travis error on functional tests seems to be because of a minikube error.

W0125 15:54:45.089355    4821 out.go:181] X Exiting due to RSRC_INSUFFICIENT_CORES: Requested cpu count 1 is less than the minimum allowed of 2
493X Exiting due to RSRC_INSUFFICIENT_CORES: Requested cpu count 1 is less than the minimum allowed of 2
494I0125 15:54:45.089376    4821 out.go:119] 
495
496

[yliaog]

/assign @fabianvf

[MridulS]

/retest

[k8s-ci-robot]

@MridulS: Cannot trigger testing until a trusted user reviews the PR and leaves an /ok-to-test message.

In response to this:

/retest

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[yliaog]

/ok-to-test

[MridulS]

/retest

[MridulS]

Travis seems to be failing due to an unrelated test. Any ideas what's happening here? Travis is happy now :D

[MridulS]

Just wanted to check in to see if this looks okay :)

[fabianvf]

/lgtm

[MridulS]

/assign @yliaog

[yliaog]

/approve

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[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: fabianvf, MridulS, yliaog

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