Add ability to cache docker images

[jakeleventhal]

Which project is this feature idea for?

Turborepo

Describe the feature you'd like to request

Turbo should be able to cache docker images and use those with cache hits.

Describe the solution you'd like

Implement caching with docker images.

Describe alternatives you've considered

N/A

[chris-olszewski]

Hi Jake, could you elaborate a little bit more on what you mean by having Turborepo cache docker images? Docker itself already has fairly advanced image caching.

[jakeleventhal]

sure, what im referring to is being able to cache the output of a docker build much in the same way that i would cache any other output in turbo. For instance, i should be able to run a script "image" via turbo image which builds a docker image, and specify the image as an output (similar to how bazel works). then in ci, my remote cache should be able to recognize a cache hit, and download the docker artifact as an output

[mehulkar]

@jakeleventhal what happens when you do that today? I imagine the artifact size is pretty large, so writing to cache (especially remote cache) could take a while, but turbo shouldn't have an opinion over what the outputs are. If you're running into issues, can you provide a reproduction repo?

[jakeleventhal]

how exactly would you even specify a docker image output?

[mehulkar]

sorry, it's been ~a decade since I used docker, does it not create the image on your local disk first? Is it no longer a local directory or file on your filesystem when you create the image?

[jakeleventhal]

They get saved to a ~/.docker directory

[mehulkar]

Is it possible to customize that location such that you could put it in the repo location? (I assume that even if that is possible it may interfere with other docker operations). That said, it seems like there are a couple general purpose features here:

• outputs outside the repo root (which is already possible, I think)
• or maybe a --cache-dir per task, so in your case the image task could specify the location

Will bring this up with the team!

[jakeleventhal]

There isn't a way to specify this unfortunately.