`create webhook`: return error when used with a core type

[estroz]

When I run kubebuilder create webhook on a core type, ex. v1.Pod, the command attempts to define methods on a non-existent locally-defined type. Instead, the command should return an error explaining that core types are not supported by this command.

$ go version
go version go1.15.2 linux/amd64
$ kubebuilder version
Version: main.version{KubeBuilderVersion:"v3.0.0-alpha.0-195-g37485126", KubernetesVendor:"unknown", GitCommit:"37485126f95ceb2e92a86497c31f400c8b89f957", BuildDate:"2021-04-12T18:30:56Z", GoOs:"linux", GoArch:"amd64"}
$ cat go.mod | grep controller-runtime
sigs.k8s.io/controller-runtime v0.7.2

/kind bug

[camilamacedo86]

IHMO, we ought to not create this message and instead of that, we can spend the effort to implementing the RFE: https://github.com/kubernetes-sigs/kubebuilder/issues/1999. (see my comments there )

We can change here: https://github.com/kubernetes-sigs/kubebuilder/blob/master/pkg/plugins/golang/v3/webhook.go#L107 for:

• If is core type then update the PROJECT file accordingly and scaffold the webhook
• if is external-type (we need a new flag for that) then, do the same.

[estroz]

This solution is more of a holdover until something like what is suggested here is implemented and kustomize-able resources are generated correctly for core/external types.

Alternatively the holdover can be skipped entirely if the Handler implementation can be completed without an EP, which I think it can.

@kopiczko if you'd like to work on either this and/or implement core/external type support in create webhook, feel free to assign yourself!

[kopiczko]

Cool, thanks, I'll look into this and check what I can do in the following days. Possibly starting wit the error message is a good warmup for me.

[kopiczko]

Hi @estroz,

I was trying to think what would be the good way to fix this and found that doesn't only apply to the core types.

In general:

$ kubebuilder create api --group "mygroup" --version "v1" --kind "MyKind" --controller=true --resource=false
Writing scaffold for you to edit...
controllers/mykind_controller.go
Update dependencies:
$ go mod tidy

$ kubebuilder create webhook --group "mygroup" --version "v1" --kind "MyKind" --defaulting
Writing scaffold for you to edit...
api/v1/mykind_webhook.go

$ tree api
api
└── v1
    ├── mykind_webhook.go
    └── webhook_suite_test.go

1 directory, 2 files

Setting --controller=false gives the same output. You can replace --group "mygroup" with --group "" and the output will be the same.

So I'd say the issue is that webhook methods are generated on non-existent resource in general?

[Adirio]

More than an issue, they are a unsupported feature. We only support webhooks for types we have scaffolded ourselves.

[kopiczko]

Shouldn't generating scaffolding for the resource also be forbidden in kubebuilder create api?

[estroz]

Theoretically create api can create a controller for a core type. When I run kubebuilder create api --controller, I get a controller for no resource, so technically it does work right now. I propose better handling of this situation by accepting some import path that can then be used in a controller in #1999. The --resource flag should generate an error though.

[fejta-bot]

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/close

[k8s-ci-robot]

@k8s-triage-robot: Closing this issue.

In response to this:

The Kubernetes project currently lacks enough active contributors to adequately respond to all issues and PRs.

This bot triages issues and PRs according to the following rules:

• After 90d of inactivity, lifecycle/stale is applied
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/close

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[kebyn]

/reopen

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[estroz]

/reopen /lifecycle frozen

[k8s-ci-robot]

@estroz: Reopened this issue.

In response to this:

/reopen /lifecycle frozen

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This issue has not been updated in over 1 year, and should be re-triaged.

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/remove-triage accepted

[cloudziu]

Hello, do you plan to add scaffolding webhooks for core resources?