tinygo with work kubernetes crds?

[zirain]

I want to use TinyGo with following code:

package main

import (
	"fmt"

	workloadv1alpha1 "github.com/karmada-io/karmada/examples/customresourceinterpreter/apis/workload/v1alpha1"
	configv1alpha1 "github.com/karmada-io/karmada/pkg/apis/config/v1alpha1"
	"github.com/karmada-io/karmada/pkg/resourceinterpreter/customizedinterpreter/webhook"
	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
	"k8s.io/apimachinery/pkg/runtime"
)

func main() {

}

func Interpreter(req *webhook.RequestAttributes) *webhook.ResponseAttributes {
	switch req.Operation {
	case configv1alpha1.InterpreterOperationInterpretReplica:
		return responseWithExploreReplica(req)
	default:
		return nil
	}
}

func responseWithExploreReplica(req *webhook.RequestAttributes) *webhook.ResponseAttributes {
	wantedWorkload := &workloadv1alpha1.Workload{}
	if err := convertToTypedObject(req.Object, wantedWorkload); err != nil {
		return nil
	}
	return &webhook.ResponseAttributes{
		Replicas: *wantedWorkload.Spec.Replicas + 1,
	}
}

// convertToTypedObject converts an unstructured object to typed.
func convertToTypedObject(in, out interface{}) error {
	if in == nil || out == nil {
		return fmt.Errorf("convert objects should not be nil")
	}

	switch v := in.(type) {
	case *unstructured.Unstructured:
		return runtime.DefaultUnstructuredConverter.FromUnstructured(v.UnstructuredContent(), out)
	case map[string]interface{}:
		return runtime.DefaultUnstructuredConverter.FromUnstructured(v, out)
	default:
		return fmt.Errorf("convert object must be pointer of unstructured or map[string]interface{}")
	}
}

but got error like following:

# [k8s.io/apimachinery/third_party/forked/golang/reflect](http://k8s.io/apimachinery/third_party/forked/golang/reflect)
../../../../../../pkg/mod/k8s.io/apimachinery@v0.25.4/third_party/forked/golang/reflect/deep_equal.go:126:15: v1.UnsafeAddr undefined (type "reflect".Value has no field or method UnsafeAddr)
../../../../../../pkg/mod/k8s.io/apimachinery@v0.25.4/third_party/forked/golang/reflect/deep_equal.go:127:15: v2.UnsafeAddr undefined (type "reflect".Value has no field or method UnsafeAddr)
../../../../../../pkg/mod/k8s.io/apimachinery@v0.25.4/third_party/forked/golang/reflect/deep_equal.go:314:15: v1.UnsafeAddr undefined (type "reflect".Value has no field or method UnsafeAddr)
../../../../../../pkg/mod/k8s.io/apimachinery@v0.25.4/third_party/forked/golang/reflect/deep_equal.go:315:15: v2.UnsafeAddr undefined (type "reflect".Value has no field or method UnsafeAddr)
make: *** [Makefile:7: build-wasm] Error 1

How can I make it work?

[dgryski]

TinyGo still has issues with tinygo support, but in this particular case it seems like it's trying to use the vendored upstream Go reflect package which will definitely not work with tinygo.

[zirain]

any plan to support it? it will be useful to project like https://www.kubewarden.io/

[dgryski]

We can improve reflect support for the tinygo parts, but we won't be able build and run the upstream forked Go package. The reflect internals are too tied to the compiler.

[zirain]

will #2640 fix type "reflect".Value has no field or method UnsafeAddr ?

[aykevl]

TinyGo still has issues with reflect support, but in this particular case it seems like it's trying to use the vendored upstream Go reflect package which will definitely not work with tinygo.

It's actually not that bad. It's called "forked" but in fact it's just a wrapper around the reflect package. Adding UnsafeAddr should be relatively easy (I could do that after #2640 has landed, to avoid conflicts).

will #2640 fix type "reflect".Value has no field or method UnsafeAddr ?

No. It is a refactor and therefore does not add new functionality.

[zirain]

yes, I take a quick look of the implement in tinygo, seems the root cause is unimplement of Addr() or UnsafeAddr
thanks for your follow up

[zirain]

@aykevl #2640 is merged, can you take a look at this now?

[aykevl]

@zirain: this is something @dgryski has been working on. See #3470 for the work in progress.

[zirain]

#3470 implement Addr(), any plan about UnsafeAddr?

[dgryski]

I will work on getting these implemented, but it's just me working on it and reflect has a lot of moving parts.

[zirain]

xref: #3554 #3560

[dgryski]

Note that these particular issues fix the build issues but for full functionality all the outstanding reflect PRs should be merged.

[zirain]

I test with latest commit on dev, still got type "reflect".Value has no field or method UnsafeAddr, that surprise me.

[aykevl]

@zirain it's in the dev branch. Are you sure you're using the correct tinygo binary? (Try tinygo clean and then tinygo env TINYGOROOT to verify it points to the repository).

[zirain]

get more errors about:

vendor/k8s.io/utils/net/port.go:124:20: undefined: net.ResolveUDPAddr
vendor/k8s.io/utils/net/port.go:128:20: undefined: net.ListenUDP