cli: set a timeout for the initial connection ping

[nicks]

Note that this does not fully fix the referenced issue, but at least makes sure that API clients don't hang forever on the initialization step. (now it hangs on a later request)

See: https://github.com/docker/cli/issues/3652

- What I did see attached issue

- How I did it see attached issue

- How to verify it The docker ps in the attached issue still hangs, but now hangs at a later step. You can see this by running kill -s ABRT on the hung process to see where it's hanging

- Description for the changelog Add timeout to initial docker client initialization

- A picture of a cute animal (not mandatory but encouraged)

[codecov-commenter]

Codecov Report

Merging #3663 (26a1841) into master (b75c262) will increase coverage by 0.08%. The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #3663      +/-   ##
==========================================
+ Coverage   59.02%   59.11%   +0.08%     
==========================================
  Files         289      289              
  Lines       24626    24684      +58     
==========================================
+ Hits        14535    14591      +56     
- Misses       9218     9220       +2     
  Partials      873      873              

[nicks]

@vvoland is there anything left you need from me on this? (i don't have permission to merge the PR)

[vvoland]

Looks good to me, but maybe @thaJeztah would like to take a look?

[thaJeztah]

I did a quick squash and rebase of this PR in https://github.com/docker/cli/pull/3722

(I'll rebase this one to restore the WithInitializeTimeout() for further discussion 👍

[nicks]

squashed this one!

ya, the WithInitializeTimeout() bit isn't hard to add, and i'm not attached to it.

[nicks]

got merged in https://github.com/docker/cli/pull/3722