need more relevant directory in failure message when Dockerfile is missing #4248
Description
It gives an error message, but not as helpful as it can get:
$ DOCKER_BUILDKIT=1 docker build .
[+] Building 0.0s (2/2) FINISHED
=> [internal] load .dockerignore 0.0s
=> => transferring context: 02B 0.0s
=> [internal] load Dockerfile 0.0s
=> => transferring dockerfile: 02B 0.0s
failed to read dockerfile: open /var/lib/docker/tmp/buildkit-mount217942563/Dockerfile: no such file or directory
For the directory I was working from, more suitable to have:
failed to read dockerfile: open /home/andrewhsu/covfefe/Dockerfile: no such file or directory