Make checkout configurable

[c2h5oh]

• [ ] allow disabling checkout
• [ ] allow setting checkout-specific env vars (BUILDKITE_GIT_CLONE_FLAGS, BUILDKITE_GIT_FETCH_FLAGS) - you'd normally do it using a plugin but since this plugins also does checkout you can't

[DrJosh9000]

Hi @c2h5oh, for disabling checkout, would setting BUILDKITE_REPO="" be possible for you?

[c2h5oh]

Sure. Where would I be doing that? in step env?

[DrJosh9000]

Currently, changing BUILDKITE_REPO must be done using either an environment or pre-checkout agent hook. The pipeline's configured repo would override attempts to set it with e.g. step env.

[c2h5oh]

Wouldn't that disable checkout for all steps?

[DrJosh9000]

I agree that this is probably not ideal, but since hooks are executed in each step, you could conceivably vary BUILDKITE_REPO based on some other variable set in the step env:

#!/usr/bin/env bash
if [[ "${SKIP_CHECKOUT:false}" == "true" ]]; then
    export BUILDKITE_REPO=""
fi

[c2h5oh]

Well, since we agree this is not ideal would you accept a PR that would add checkout control to this plugin, or do you consider it out of scope?

[DrJosh9000]

I was trying to figure out the best place to add these controls, since it might be a more general agent issue. We've discussed it and I think we agree there ought to be better control over checkout specifically for the k8s stack. We're happy for, say, a checkout section in the kubernetes plugin definition, but we don't have a firm idea of what that looks like yet. If you're willing to make a PR exploring this, please do!

[c2h5oh]

I was thinking about combining features present in plugins normally used to implement this.

checkout:
    disableCheckout: false
    cloneFlags: ""
    fetchFlags: ""

• setting disableCheckout to true would replace checkout hook with NOP, like this plugin does https://github.com/uber-workflow/run-without-clone-buildkite-plugin/blob/master/hooks/checkout
• setting values of the other two would set values of BUILDKITE_GIT_CLONE_FLAGS, BUILDKITE_GIT_FETCH_FLAGS in pre-checkout like this plugin https://github.com/Hivebrite/git-flags-buildkite-plugin/blob/main/hooks/pre-checkout

[bpoland]

👋 hey there, was having trouble getting hooks to work at all but I figured it out -- not sure if any of you had the same issue?

https://github.com/buildkite/agent-stack-k8s/pull/258