Document if kubeclient / restclient is threadsafe or not

[grosser]

Would be nice to have a "Not threadsafe, use one kubeclient per Thread" or the opposite in the docs somewhere.

[cben]

I suspect it is but don't know for sure.

• is rest-client thread-safe?
• is http gem thread-safe?
• I think the only Client mutation during use is lazy discovery. Is it safe?
• is Config thread-safe?

[grosser]

yeah, client mutation is not threadsafe, I already run into that one :D

[cben]

I think we want it to become thread-safe. That's the only sane contract for a high-level library...

Do you know details on problems you saw?
Should discovery take a mutex, or would that risk one slow request blocking everything?
Should we let multiple parallel discovery requests to "race", but make sure the results are "committed atomically"? (I'd rather not, premature buggization...)

[grosser]

having an instance-mutex around discoveries should be cheap and make it threadsafe
alternative would be to initialize it with 'threadsafe: true' and then just eager-discover