ws_client.py uses select.poll without checking module existence

[seanpang-vmware]

What happened (please include outputs or screenshots):
since version:
Kubernetes API Version: v1.21.7

Bug or Regression
Fixed #741, an issue which prevented Kubernetes cluster api-tokens from exec-plugin auth providers from being refreshed after expiry. (#250, @emenendez)
Use select.poll() for exec on linux/darwin to improve scalability of WSClient (#268, @jsun-splunk)

ws_client.py uses select.poll to exec but did not check if this module exist

if process is monkey patched, this will lead to ApiException.

What you expected to happen:
check if select.poll exist, if not use select.select instead.
/usr/local/lib/python3.8/dist-packages/kubernetes/stream/ws_client.py line 182

       if sys.platform.startswith('linux') or sys.platform in ['darwin']:
            poll = select.poll()
            poll.register(self.sock.sock, select.POLLIN)
            r = poll.poll(timeout)
            poll.unregister(self.sock.sock)

How to reproduce it (as minimally and precisely as possible):
A simple way to reproduce

root@192-161-133-176:/opt/vmware/nsx-cli/bin/python/cli# python3
Python 3.8.10 (default, Sep 28 2021, 16:10:42)
[GCC 9.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.

import select
select.poll()
<select.poll object at 0x7f24f52df390> <----- no monkey patch, works fine

from eventlet import monkey_patch
monkey_patch()

select.poll()
Traceback (most recent call last):
File "", line 1, in
AttributeError: module 'select' has no attribute 'poll' <------ monkey patched, attr lost

from eventlet issue page, this is a design intent:
eventlet/eventlet#608 (comment)

Anything else we need to know?:

Environment:

• Kubernetes version (kubectl version): 1.22
• OS (e.g., MacOS 10.13.6): Ubuntu 20.04
• Python version (python --version) 3.8
• Python client version (pip list | grep kubernetes) 21.7.0

[roycaihw]

@seanpang-vmware Thanks for reporting! Is select.poll only existing in linux / darwin platforms? If so, would you like to send a PR?

[seanpang-vmware]

@seanpang-vmware Thanks for reporting! Is select.poll only existing in linux / darwin platforms? If so, would you like to send a PR?

No, the issue happened because eventlet is monkey patched, beause select.poll is not thread safe, so eventlet will remove this method after monkey patch. so calling this method will cause "No such module" excpetion.

try this:

import select
from eventlet import monkey_patch
monkey_patch()

select.poll()

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/lifecycle stale

[k8s-triage-robot]

The Kubernetes project currently lacks enough active contributors to adequately respond to all issues and PRs.

This bot triages issues and PRs according to the following rules:

• After 90d of inactivity, lifecycle/stale is applied
• After 30d of inactivity since lifecycle/stale was applied, lifecycle/rotten is applied
• After 30d of inactivity since lifecycle/rotten was applied, the issue is closed

You can:

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/lifecycle rotten

[Akasurde]

/remove-lifecycle rotten

[Akasurde]

/assign