fix: allow recursive dry-run over local sources

[niveau0]

This PR tries to fix the issue using flux build with dry-run and recursion.

We have a setup with nested kustomizations and want to render the whole tree
as yaml files, including postBuild substitutions. Afterwards, this should be
checked via kube-linter.

Currently this seems not possible(?) with the flux-cli together with dry-run,
therefore I made some changes.
Since I don't know all the use cases for flux build, it is hard to tell if this
breaks anything.

Maybe someone with deeper knowledge can review the changes.

The command I use is similar to this:

flux build kustomization flux-system \
--recursive \
--path ./clusters/dev/mykustomizations \
-n flux-system \
--local-sources GitRepository/flux-system/flux-system=./ \
--dry-run \
--kustomization-file ./clusters/dev/flux-system/gotk-sync.yaml

[bkreitch]

Seems reasonable to me. I would just switch branches of if b.dryRun and else in build() and revert blank lines except at line 370. And add following test to cmd/flux/build_kustomization_test.go in TestBuildLocalKustomization:

{
	name:       "build with recursive in dry-run mode",
	args:       "build kustomization podinfo --kustomization-file " + tmpFile + " --path ./testdata/build-kustomization/podinfo-with-my-app --recursive --local-sources GitRepository/default/podinfo=./testdata/build-kustomization --dry-run",
	resultFile: "./testdata/build-kustomization/podinfo-with-my-app-result.yaml",
	assertFunc: "assertGoldenTemplateFile",
},

[niveau0]

@bkreitch , thanks for the advice, I will add a test. But I'm not sure what you mean with the if and else branches, since the if and else in the PR are not related?

[bkreitch]

But I'm not sure what you mean with the if and else branches, since the if and else in the PR are not related?

@niveau0 I mean to reverse if condition so it will be like:

if b.dryRun {
	liveKus = b.kustomization
} else {
	liveKus, err = b.getKustomization(ctx)
	if err != nil {
...

[bkreitch]

@niveau0 and for the test - I think that if you'll put my snippet from above into TestBuildLocalKustomization() instead of TestBuildKustomization() it should be enough and additional files are not needed.

[niveau0]

@niveau0 and for the test - I think that if you'll put my snippet from above into TestBuildLocalKustomization() instead of TestBuildKustomization() it should be enough and additional files are not needed.

@bkreitch ah ok got it now, I think I failed to see the 'Local' part in TestBuildLocalKustomization and got confused.