add "env" driver that connects to $BUILDKIT_HOST

[AkihiroSuda]

This driver allows creating a buildx instance directly pointing to the existing buildkit endpoint.

docker buildx create --driver=env unix:///var/lib/buildkitd.sock
docker buildx create --driver=env uses BUILDKIT_HOST env value with UNIX sock default.

I guess TLS info is just passed with a custom driver-opt:

docker buildx create --driver=env --driver-opt ca=mycafile.pem https://foobar

rm/stop commands are no-op in this driver.

A better name could be "remote".

[tonistiigi]

It's possible this could be combined with #21 as #21 doesn't really have an endpoint.

[tonistiigi]

Otoh, combining may add complexity as #21 is linux only and may require credentials while this could work from anywhere. It would be easier to do this split by using different drivers.

[pchico83]

+1 This would be awesome!

[Shaked]

Any updates regarding this issue? Is it there another way to run buildx with a remote buildkitd?

[developer-guy]

Hello folks, kindly ping 🙋🏻‍♂️✌️ Are there any updates? We (w/@Dentrax) thought that, if it happens, we can be able to use the buildkitd running in lima-vm for this. So, we are so excited about this.

[tonistiigi]

Nobody is working on it afaik. It should quite easy to add it If somebody wants to take it on. Most of the work would probably be to make sure that CI would test this driver.