Add --cache-file flag to `render` command

[dinvlad]

I'm using skaffold render in my CI/CD GitOps pipeline, and would like to reuse Skaffold cache file between runs, to avoid the dreaded Checking cache... Not found. Building. However, I need to write this cache file to a specific location that's not $HOME/.skaffold/cache, because that directory is not preserved between my CI steps.

I could move the directory explicitly before/after running skaffold render, but it's pretty inconvenient. Other commands (build, dev etc.) expose --cache-file flag to specify its location, and I'd like it to be added to render as well, if possible.

Alternatively, if there's any way to set the "Skaffold directory" (from the default $HOME/.skaffold), that could work too (and maybe even better!)

Expected behavior

skaffold render has --cache-file flag

Actual behavior

--cache-file flag is not available for skaffold render

Information

• Skaffold version: v1.34.0
• Operating system: Ubuntu 20.10
• Installed via: Cloud Code
• Contents of skaffold.yaml: N/A

Steps to reproduce the behavior

1. Run skaffold render --cache-file=.skaffold/cache
2. Observe the result:

unknown flag: --cache-file
See 'skaffold render --help' for usage.

[briandealwis]

The cleaner approach (IMHO) is to instead save the list of built artifacts with skaffold build --file-output artifacts.json. This artifacts.json will have a list of artifact names as used in the skaffold.yaml and the corresponding image tag and digests. You would then use that list with skaffold render --build-artifacts artifacts.json.

[dinvlad]

Thanks for the suggestion, @briandealwis ! That seems like a reasonable workaround for now. It would still be nice to handle it all in one command, of course.

[tejal29]

removing triage/discuss. Though this seems like a valid reasonable request, the team does not have the bandwidth to prioritize this now. Adding a ci-cd label for future.