add retries for 502

[fedordikarev]

Fix: #750

• Retry only 5xx errors (502 for now) as dont need to retry bad login/passwords
• Sleep 10s before attempts. It could be configurable, but shouldn't bit less than 10s.
• Delay could be with exponential backoff, or just simple approach with no more than 3 attempts and constant 10s delay, IMO, should be enough for docker login

[fedordikarev]

hi @crazy-max !

what do you think about these changes?

[bayandin]

Hey @crazy-max and @offensive-vk,

Is there anything we can do to get this PR merged?
Or, if the PR suggests the way you wouldn't like to proceed, could you please let us know as well?

Thank you both and Happy New Year!

[offensive-vk]

Looks Good!

[fedordikarev]

well, I'm going to close that PR, as it's:

1. first of all, it doesn't work :-)
2. it was created when I had 15 minutes free time in the train
3. so it's not perfect, not even good :-)
4. and here is PR I did when I had more time and did it from home: Add moderate way to retry docker login failures #849