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.
kubernetes/gengo@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