Kubebuilder: Add support for interface member

[fiftoine]

Hi,

I have a resource type that has a interface{} type.

When running go run vendor/sigs.k8s.io/controller-tools/cmd/controller-gen/main.go crdI get an error :

2018/12/13 08:35:47 Unknown supported Kind Interface

Actually, This field could contain string or int or bool but I don't want to create a IntOrStringOrBool type. Is there a workaround or is it a bug?

Thanks

[droot]

It should not error-out for interface{} type.
@sohankunkerkar can you pl. take a look at this ?

[sohankunkerkar]

@fiftoine Could you please help me out with your test case (like an example )here? Just wanted to make sure that I'm not missing out on any information.

[tantona]

So happy this issue is already open - I just ran into this myself!

Are there any workarounds? @fiftoine did you get this figured out?

[sohankunkerkar]

@tantona Could you please provide the test case that you're using here. It would help me in debugging this issue.

[andersjanmyr]

@sohankunkerkar Just declare a new type, like this:

type InterfaceExample struct {
    Inter interface{} `json:"inter"`
}

This will lead to an error like this:

$ make
go generate ./pkg/... ./cmd/...
F0114 14:33:10.565683   65790 main.go:82] Error: Failed executing generator: some packages had errors:
errors in package "gecgithub01.walmart.com/wce/marquis-mca/pkg/apis/marquis/v1beta1":
unable to format file "/Users/vn0wxf9/gocode/src/gecgithub01.walmart.com/wce/marquis-mca/pkg/apis/marquis/v1beta1/zz_generated.deepcopy.go" (62:39: expected ';', found '{' (and 5 more errors)).

[andersjanmyr]

Adding a type alias for interface{} changes the error

type Inter interface{}
type InterfaceExample struct {
    Inter Inter `json:"inter"`
}

to this

$ make
go generate ./pkg/... ./cmd/...
go fmt ./pkg/... ./cmd/...
go vet ./pkg/... ./cmd/...
# gecgithub01.walmart.com/wce/marquis-mca/pkg/apis/marquis/v1beta1
pkg/apis/marquis/v1beta1/zz_generated.deepcopy.go:69:23: in.Inter.DeepCopyInter undefined (type Inter is interface with no methods)
# gecgithub01.walmart.com/wce/marquis-mca/pkg/apis/marquis/v1beta1 [gecgithub01.walmart.com/wce/marquis-mca/pkg/apis/marquis/v1beta1.test]
pkg/apis/marquis/v1beta1/zz_generated.deepcopy.go:69:23: in.Inter.DeepCopyInter undefined (type Inter is interface with no methods)
make: *** [vet] Error 2

[andersjanmyr]

I think something like Mitchell Hashimoto's copystructure could be used to solve this.
https://godoc.org/github.com/mitchellh/copystructure

[sohankunkerkar]

@andersjanmyr Thanks for the detailed analysis. I understood what's the problem here. Let me go through it and will get back to you soon.

[andersjanmyr]

@sohankunkerkar I looked at it some more and to be able to add this functionality the generator has to be altered. Here's an example that works (but is far from perfect). I need to add support to all interfaces and make sure that the copystructure package is included with dep.
https://github.com/kubernetes/gengo/compare/master...andersjanmyr:add_support_for_interface

[andersjanmyr]

After the above change is applied, the following patch needs to be applied to sigs.k8s.io/controller-tools to generate a property with type: object in the CRD.

--- a/vendor/sigs.k8s.io/controller-tools/pkg/internal/codegen/parse/crd.go
+++ b/vendor/sigs.k8s.io/controller-tools/pkg/internal/codegen/parse/crd.go
@@ -198,6 +198,8 @@ func (b *APIs) typeToJSONSchemaProps(t *types.Type, found sets.String, comments
                v, s = b.typeToJSONSchemaProps(t.Elem, found, comments, false)
        case types.Alias:
                v, s = b.typeToJSONSchemaProps(t.Underlying, found, comments, false)
+       case types.Interface:
+               v, s = b.parseObjectValidation(t, found, comments, isRoot)

[sohankunkerkar]

@andersjanmyr That's awesome. I was planning to handle this condition in the controller-tools itself.
https://github.com/kubernetes-sigs/controller-tools/compare/master...sohankunkerkar:interface?expand=1
I did not change anything in gengo package

[andersjanmyr]

@sohankunkerkar How does the generated copy code look? The zz_generated.deepcopy.go must make a deep copy using reflection for interfaces. I don't think you can get that to work without using reflection.

[j-vizcaino]

Stumbled upon this today as well. Reading the thread of comments it seems two issues are actually entangled here:

• one is about generation of the CRD
• one is about generation of the deepcopy code

My use-case is a bit similar to the one described above, although in my case, the structure member is a map[string]interface{}. I was able to circumvent the deepcopy issue by creating the DeepCopy and DeepCopyInto functions manually but I can't get past the CRD.

Here is the code that handles the copy (maybe helpful to other people):

// +k8s:deepcopy-gen=false
type ExtraFields map[string]interface{}

func (in *ExtraFields) DeepCopyInto(out *ExtraFields) {
    if in == nil {
        *out = nil
    } else {
        *out = runtime.DeepCopyJSON(*in)
    }
}

func (in *ExtraFields) DeepCopy() *ExtraFields {
    if in == nil {
        return nil
    }
    out := new(ExtraFields)
    in.DeepCopyInto(out)
    return out
}

[sohankunkerkar]

@j-vizcaino Could you provide your feedback over here?
https://github.com/kubernetes-sigs/controller-tools/pull/126

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[DirectXMan12]

this should have been fixed in the latest release of CT, IIRC

[austince]

I'm using version 2.0.0-beta.0 of Kubebuilder and still seeing this problem. I've verified that I'm using the latest version of CT, 0.2.0-beta.4. My interface looks like this:

type DeploymentTargetSpec struct {
    DeploymentPatchSet []interface{} `json:"deploymentPatchSet"`
}

Seeing the error message:

github.com/.../api/v1beta1:-: name requested for invalid type interface{}
github.com/.../api/v1beta1:-: invalid slice element type interface{}

Is there something I'm still doing wrong? It's also worth noting that this happens without the slice as well.

[szediktam]

no fixed in master. @DirectXMan12
go run vendor/sigs.k8s.io/controller-tools/cmd/controller-gen/main.go crd paths=./pkg/apis/aiops/... output:crd:dir=/tmp/crds
error:
map values must be a named type, not *ast.InterfaceType

same problem:
https://github.com/kubernetes-sigs/controller-tools/issues/294

[DirectXMan12]

I've replied on the equivalent controller-tools issue. Please direct all comments there.

[DirectXMan12]

I've locked this in the hopes that we can keep discussion in one place, not to discourage filing of issues. In general, generation issues should be discussed in the controller-tools repo.