News for hackers. Stuff that matters.
Re:Defence Against the Docker Arts by bsilvereagle on Thursday April 04, 2019 @12:49AM (#19569414)
This feature currently does not work with the OS X ssh agent:

https://github.com/docker/for-mac/issues/410

Re:Defence Against the Docker Arts by auvrw on Thursday April 04, 2019 @08:27AM (#19571333)
ssh access at build time via buildkit works on os x

https://medium.com/@tonistiigi/build-secrets-and-ssh-forward...

the link you've supplied regards ssh access when running docker images, not when building them.

... i did notice that for lots of downloads, it is somewhat slower, or perhaps more prone to lag, than authentication from inside the running image.