Allow setting timeout when running docker buildx inspect

[CamJN]

Description

When I run docker buildx inspect but one of my ssh build hosts isn't up, the timeout is very slow. I'd prefer it to be very fast so that I can either turn on the host or ignore the error faster. Most of the time I'm running that command as part of a script to make sure that the build config is setup, so I don't need to have the host running, but the timeout being so big makes the script slow.

The error I'm looking for: Error: Get "http://docker.example.com/v1.48/containers/buildx_buildkit_non_native_arch/json": context deadline exceeded

the timing as-is:

real	0m20.128s
user	0m0.147s
sys	0m0.119s

What I'd like: the ability to set that context deadline to 1 or 2 seconds max.

[tonistiigi]

Maybe you can carry docker/buildx#2586

[CamJN]

Not a bad idea, i'll look into that.

[CamJN]

@tonistiigi docker/buildx#3159