Is it possible to export a tarball?

[poy]

Is it possible export a tarball instead of pushing to the local docker daemon or a container registry in the exporter?

An example of how another project accomplishes this is Kaniko's --tarPath flag.

[ekcasey]

@poy It is not currently possible, but it is something we could specify/implement in the future if there is sufficient interest. Would you be comfortable sharing your use case?

[ekcasey]

@poy Would you be providing inputs images (i.e the run-image and previous image) as tarballs as well?

[poy]

@ekcasey Our use case can be summarized as a pipeline that produces a container, analyzes it and then pushes it. Each stage expects to receive a tarball as an input.

At the moment, we don't require the inputs to be tarballs.

[jromero]

This may also be useful for the BuildKit integration. Specifically in removing the need to reimplement export.

It would require more thought but maybe the export phase could take an option to export as oci layout format. This oci layout directory or archive can then be read by the BuildKit frontend and processed to include layers and image config (labels, env vars, etc).

[jabrown85]

Note from discussion: Generating a tar means having to write all layers (as opposed to being able to skip them during publish)