Allow to specify the name of the Dockerfile

[leovct]

Background & motivation

By default, ImageBuildSpec will search for a file called Dockerfile in the build_context_dir. I would like to be able to specify the name of the Dockerfile via an optional argument.

Just like what docker build allows:

$ docker build --help | grep file
    -f, --file string                   Name of the Dockerfile (default: "PATH/Dockerfile")

Btw I'm open to work on this to get more familiar with the code base if possible :)

Desired behaviour

Here is the new specification of ImageBuildSpec with an optional additional argument called file.

image = ImageBuildSpec(
      # Name to give built image
      # MANDATORY
      image_name="kurtosistech/example-datastore-server"
      
      # Locator to build context within the Kurtosis package
      # MANDATORY
      build_context_dir="./server"

      # Name of the Dockerfile
      # By default, Kurtosis expects a Dockerfile at the root of the build context.
      # OPTIONAL
      file="mycustomfile.Dockerfile"
      
      # Stage of image build to target for multi-stage container image
      # OPTIONAL
      target_stage=""
)

How important is this to you?

Nice to have; this feature would make using Kurtosis more enjoyable.

What area of the product does this pertain to?

Other: anything not covered by the above

[tedim52]

Hey @leovct ! This is definitely something we want to support. Thanks for letting us know this would be helpful for you so we can prioritize it internaly!

[mieubrisse]

Thanks @leovct ; this would help with the applicability of ImageBuildSpec! If we can call this build_file rather than file (to pattern-match build_context_dir and build_args like you suggested in #2214) I'm down to get this in! Would you be open to submitting a PR? It's the same code as in your other ticket:

kurtosis/container-engine-lib/lib/backend_interface/objects/image_build_spec/image_build_spec.go

Line 15 in be97c38

type privateImageBuildSpec struct {

[leovct]

Yep happy to take a look :)