Cannot use downward API in `PackageBuild`

[mamachanko]

What steps did you take:

1. kctrl package init

2. Update PackageBuild to read values from the downward API

   apiVersion: kctrl.carvel.dev/v1alpha1
   kind: PackageBuild
   metadata:
     creationTimestamp: null
     name: downward.example.com
   spec:
     release:
     - resource: {}
     template:
       spec:
         app:
           spec:
             deploy:
             - kapp: {}
             template:
             - ytt:
                 paths:
                 - carvel
                 valuesFrom:
                 - downwardAPI:
                     items:
                     - kubernetesAPIs: {}
                       name: k8s_gvs
             - kbld: {}
         export:
         - imgpkgBundle:
             useKbldImagesLock: true
           includePaths:
           - carvel

3. Release/build the package

   kctrl package release --version 0.0.0-mamachanko --tag 0.0.0-mamachanko --copy-to build --yes

What happened:

Prerequisites
1. Host is authorized to push images to a registry (can be set up by running
`docker login`)
2. `package init` ran successfully.

The bundle created needs to be pushed to an OCI registry. (format:
<REGISTRY_URL/REPOSITORY_NAME>) e.g. index.docker.io/k8slt/sample-bundlekbld builds images when necessary and ensures that all image references are
resolved to an immutable reference
Building images and resolving references
panic: Not implemented

goroutine 1 [running]:
github.com/vmware-tanzu/carvel-kapp-controller/cli/pkg/kctrl/local.(*MinCoreClient).Discovery(0xc000865ee0)
        github.com/vmware-tanzu/carvel-kapp-controller/cli/pkg/kctrl/local/min_core_client.go:94 +0x25
github.com/vmware-tanzu/carvel-kapp-controller/pkg/componentinfo.(*ComponentInfo).KubernetesAPIs(0x21a48c8?)
        github.com/vmware-tanzu/carvel-kapp-controller@v0.46.0/pkg/componentinfo/component_info.go:80 +0x2d
github.com/vmware-tanzu/carvel-kapp-controller/pkg/app.(*App).template.(*App).buildDownwardAPIAdditionalValues.func3()
        github.com/vmware-tanzu/carvel-kapp-controller@v0.46.0/pkg/app/app_template.go:96 +0x3f
github.com/vmware-tanzu/carvel-kapp-controller/pkg/template.DownwardAPIValues.AsYAMLs({{0xc000022480, 0x1, 0x1}, {{{0x0, 0x0}, {0x0, 0x0}}, {{0x271800b, 0xd}, {0x2713bbf, ...}, ...}}, ...})
        github.com/vmware-tanzu/carvel-kapp-controller@v0.46.0/pkg/template/downward_api_values.go:74 +0x519
github.com/vmware-tanzu/carvel-kapp-controller/pkg/template.Values.writeFromDownwardAPI({{0xc00032e540, 0x1, 0x1}, {0xc0003788d0, 0xc0003788c0, 0xc0003788e0}, {{0x271800b, 0xd}, {0x2713bbf, 0x9}, ...}, ...}, ...)
        github.com/vmware-tanzu/carvel-kapp-controller@v0.46.0/pkg/template/values.go:117 +0x58
github.com/vmware-tanzu/carvel-kapp-controller/pkg/template.Values.AsPaths({{0xc00032e540, 0x1, 0x1}, {0xc0003788d0, 0xc0003788c0, 0xc0003788e0}, {{0x271800b, 0xd}, {0x2713bbf, 0x9}, ...}, ...}, ...)
        github.com/vmware-tanzu/carvel-kapp-controller@v0.46.0/pkg/template/values.go:74 +0x51b
github.com/vmware-tanzu/carvel-kapp-controller/pkg/template.(*Ytt).template(0xc000395080, {0xc00030e070, 0x62}, {0x0?, 0x0})
        github.com/vmware-tanzu/carvel-kapp-controller@v0.46.0/pkg/template/ytt.go:66 +0x588
github.com/vmware-tanzu/carvel-kapp-controller/pkg/template.(*Ytt).TemplateDir(0xc000866a60?, {0xc00030e070?, 0xc0000061a0?})
        github.com/vmware-tanzu/carvel-kapp-controller@v0.46.0/pkg/template/ytt.go:38 +0x45
github.com/vmware-tanzu/carvel-kapp-controller/pkg/app.(*App).template(0xc00017e000, {0xc00030e070, 0x62})
        github.com/vmware-tanzu/carvel-kapp-controller@v0.46.0/pkg/app/app_template.go:53 +0x139b
github.com/vmware-tanzu/carvel-kapp-controller/pkg/app.(*App).reconcileFetchTemplateDeploy(0xc00017e000)
        github.com/vmware-tanzu/carvel-kapp-controller@v0.46.0/pkg/app/app_reconcile.go:142 +0x452
github.com/vmware-tanzu/carvel-kapp-controller/pkg/app.(*App).reconcileDeploy(0xc00017e000)
        github.com/vmware-tanzu/carvel-kapp-controller@v0.46.0/pkg/app/app_reconcile.go:93 +0x65
github.com/vmware-tanzu/carvel-kapp-controller/pkg/app.(*App).Reconcile(0xc00017e000, 0x0)
        github.com/vmware-tanzu/carvel-kapp-controller@v0.46.0/pkg/app/app_reconcile.go:50 +0x2ea
github.com/vmware-tanzu/carvel-kapp-controller/pkg/app.(*CRDApp).Reconcile(...)
        github.com/vmware-tanzu/carvel-kapp-controller@v0.46.0/pkg/app/crd_app.go:121
github.com/vmware-tanzu/carvel-kapp-controller/pkg/app.(*Reconciler).Reconcile(0xc0002e80f0, {0x2996e28, 0x3757680}, {{{0x2713bbf, 0x9}, {0x271800b, 0xd}}})
        github.com/vmware-tanzu/carvel-kapp-controller@v0.46.0/pkg/app/reconciler.go:99 +0x3f4
github.com/vmware-tanzu/carvel-kapp-controller/cli/pkg/kctrl/local.(*Reconciler).Reconcile(0xc000868fd0, {{0xc000818200, 0x1, 0x1}, {0x0, 0x0, 0x0}, {0x0, 0x0, 0x0}, ...}, ...)
        github.com/vmware-tanzu/carvel-kapp-controller/cli/pkg/kctrl/local/reconciler.go:144 +0x7e5
github.com/vmware-tanzu/carvel-kapp-controller/cli/pkg/kctrl/cmd/app/release.(*AppSpecBuilder).Build(0xc000869908)
        github.com/vmware-tanzu/carvel-kapp-controller/cli/pkg/kctrl/cmd/app/release/app_spec_builder.go:102 +0x879
github.com/vmware-tanzu/carvel-kapp-controller/cli/pkg/kctrl/cmd/package/release.(*ReleaseOptions).Run(0xc0001a5400)
        github.com/vmware-tanzu/carvel-kapp-controller/cli/pkg/kctrl/cmd/package/release/release.go:127 +0x505
github.com/vmware-tanzu/carvel-kapp-controller/cli/pkg/kctrl/cmd/package/release.NewReleaseCmd.func1(0xc000593230?, {0x27141d1?, 0xa?, 0x24cd920?})
        github.com/vmware-tanzu/carvel-kapp-controller/cli/pkg/kctrl/cmd/package/release/release.go:54 +0x17
github.com/vmware-tanzu/carvel-kapp-controller/cli/pkg/kctrl/cmd.configureGlobalFlags.func1.1(0xc000213be8?, {0xc0001ea150, 0x0, 0x7})
        github.com/vmware-tanzu/carvel-kapp-controller/cli/pkg/kctrl/cmd/kctrl.go:141 +0xc3
github.com/cppforlife/cobrautil.DisallowExtraArgs.WrapRunEForCmd.func2.1(0xc000213c90?, {0xc0001ea150, 0x0, 0x7})
        github.com/cppforlife/cobrautil@v0.0.0-20221130162803-acdfead391ef/misc.go:45 +0x62
github.com/vmware-tanzu/carvel-kapp-controller/cli/pkg/kctrl/cmd.configureGlobalFlags.WrapRunEForCmd.func3.1(0x11c4d3b?, {0xc0001ea150, 0x0, 0x7})
        github.com/cppforlife/cobrautil@v0.0.0-20221130162803-acdfead391ef/misc.go:45 +0x62
github.com/vmware-tanzu/carvel-kapp-controller/cli/pkg/kctrl/cmd.configureGlobalFlags.WrapRunEForCmd.func6.1(0x7?, {0xc0001ea150, 0x0, 0x7})
        github.com/cppforlife/cobrautil@v0.0.0-20221130162803-acdfead391ef/misc.go:45 +0x62
github.com/vmware-tanzu/carvel-kapp-controller/cli/pkg/kctrl/cmd.configureTTY.func1.WrapRunEForCmd.func2.1(0xc0000c9c00?, {0xc0001ea150, 0x0, 0x7})
        github.com/cppforlife/cobrautil@v0.0.0-20221130162803-acdfead391ef/misc.go:45 +0x62
github.com/spf13/cobra.(*Command).execute(0xc00083adc0, {0xc0001ea0e0, 0x7, 0x7})
        github.com/spf13/cobra@v1.6.1/command.go:850 +0x694
github.com/spf13/cobra.(*Command).ExecuteC(0xc000232b00)
        github.com/spf13/cobra@v1.6.1/command.go:958 +0x389
github.com/spf13/cobra.(*Command).Execute(0xc0000fea40?)
        github.com/spf13/cobra@v1.6.1/command.go:895 +0x13
main.nonExitingMain()
        github.com/vmware-tanzu/carvel-kapp-controller/cli/cmd/kctrl/kctrl.go:39 +0x145
main.main()
        github.com/vmware-tanzu/carvel-kapp-controller/cli/cmd/kctrl/kctrl.go:21 +0x13

It appears as if it wants to read the downward API values from an actual cluster using the discovery client.

What did you expect:

That it just builds the package.

Anything else you would like to add:

no

Environment:

❯ kctrl --version
kctrl version 0.50.2

Succeeded

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[mamachanko]

Original thread w/ @Samze

[100mik]

We have like a "mocked" client for pieces that require talking to a cluster. I imagine a quick fix would be to supply some values for the time being.
And then eventually allow folks to supply these values as well (this is definitely the more useful one), however, we can get rid of the panic for the time being 🤔