feat: add hello world subresource (#96425)

This adds the infrastructure we need for a basic subresource.

pkg/apis/provisioning/v0alpha1/register.go

@@ -85,6 +85,7 @@ func AddKnownTypes(gv schema.GroupVersion, scheme *runtime.Scheme) error {
 	scheme.AddKnownTypes(gv,
 		&Repository{},
 		&RepositoryList{},
+		&HelloWorld{},
 	)
 	return nil
 }

pkg/apis/provisioning/v0alpha1/types.go

@@ -109,3 +109,10 @@ type RepositoryList struct {
 
 	Items []Repository `json:"items,omitempty"`
 }
+
+// +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object
+type HelloWorld struct {
+	metav1.TypeMeta `json:",inline"`
+
+	Whom string `json:"whom,omitempty"`
+}

pkg/apis/provisioning/v0alpha1/zz_generated.deepcopy.go

@@ -27,6 +27,31 @@ func (in *GitHubRepository) DeepCopy() *GitHubRepository {
 	return out
 }
 
+// DeepCopyInto is an autogenerated deepcopy function, copying the receiver, writing into out. in must be non-nil.
+func (in *HelloWorld) DeepCopyInto(out *HelloWorld) {
+	*out = *in
+	out.TypeMeta = in.TypeMeta
+	return
+}
+
+// DeepCopy is an autogenerated deepcopy function, copying the receiver, creating a new HelloWorld.
+func (in *HelloWorld) DeepCopy() *HelloWorld {
+	if in == nil {
+		return nil
+	}
+	out := new(HelloWorld)
+	in.DeepCopyInto(out)
+	return out
+}
+
+// DeepCopyObject is an autogenerated deepcopy function, copying the receiver, creating a new runtime.Object.
+func (in *HelloWorld) DeepCopyObject() runtime.Object {
+	if c := in.DeepCopy(); c != nil {
+		return c
+	}
+	return nil
+}
+
 // DeepCopyInto is an autogenerated deepcopy function, copying the receiver, writing into out. in must be non-nil.
 func (in *LocalRepository) DeepCopyInto(out *LocalRepository) {
 	*out = *in

pkg/apis/provisioning/v0alpha1/zz_generated.openapi.go

@@ -15,6 +15,7 @@ import (
 func GetOpenAPIDefinitions(ref common.ReferenceCallback) map[string]common.OpenAPIDefinition {
 	return map[string]common.OpenAPIDefinition{
 		"github.com/grafana/grafana/pkg/apis/provisioning/v0alpha1.GitHubRepository": schema_pkg_apis_provisioning_v0alpha1_GitHubRepository(ref),
+		"github.com/grafana/grafana/pkg/apis/provisioning/v0alpha1.HelloWorld":       schema_pkg_apis_provisioning_v0alpha1_HelloWorld(ref),
 		"github.com/grafana/grafana/pkg/apis/provisioning/v0alpha1.LocalRepository":  schema_pkg_apis_provisioning_v0alpha1_LocalRepository(ref),
 		"github.com/grafana/grafana/pkg/apis/provisioning/v0alpha1.Repository":       schema_pkg_apis_provisioning_v0alpha1_Repository(ref),
 		"github.com/grafana/grafana/pkg/apis/provisioning/v0alpha1.RepositoryList":   schema_pkg_apis_provisioning_v0alpha1_RepositoryList(ref),
@@ -63,6 +64,38 @@ func schema_pkg_apis_provisioning_v0alpha1_GitHubRepository(ref common.Reference
 	}
 }
 
+func schema_pkg_apis_provisioning_v0alpha1_HelloWorld(ref common.ReferenceCallback) common.OpenAPIDefinition {
+	return common.OpenAPIDefinition{
+		Schema: spec.Schema{
+			SchemaProps: spec.SchemaProps{
+				Type: []string{"object"},
+				Properties: map[string]spec.Schema{
+					"kind": {
+						SchemaProps: spec.SchemaProps{
+							Description: "Kind is a string value representing the REST resource this object represents. Servers may infer this from the endpoint the client submits requests to. Cannot be updated. In CamelCase. More info: https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#types-kinds",
+							Type:        []string{"string"},
+							Format:      "",
+						},
+					},
+					"apiVersion": {
+						SchemaProps: spec.SchemaProps{
+							Description: "APIVersion defines the versioned schema of this representation of an object. Servers should convert recognized schemas to the latest internal value, and may reject unrecognized values. More info: https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#resources",
+							Type:        []string{"string"},
+							Format:      "",
+						},
+					},
+					"whom": {
+						SchemaProps: spec.SchemaProps{
+							Type:   []string{"string"},
+							Format: "",
+						},
+					},
+				},
+			},
+		},
+	}
+}
+
 func schema_pkg_apis_provisioning_v0alpha1_LocalRepository(ref common.ReferenceCallback) common.OpenAPIDefinition {
 	return common.OpenAPIDefinition{
 		Schema: spec.Schema{

pkg/registry/apis/provisioning/hello.go

@@ -0,0 +1,62 @@
+package provisioning
+
+import (
+	"context"
+	"net/http"
+
+	"github.com/grafana/grafana/pkg/apis/provisioning/v0alpha1"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apiserver/pkg/registry/rest"
+)
+
+type helloWorldSubresource struct{}
+
+func (*helloWorldSubresource) New() runtime.Object {
+	// This is added as the "ResponseType" regardless what ProducesObject() returns
+	return &v0alpha1.HelloWorld{}
+}
+
+func (*helloWorldSubresource) Destroy() {}
+
+func (*helloWorldSubresource) NamespaceScoped() bool {
+	return true
+}
+
+func (*helloWorldSubresource) GetSingularName() string {
+	return "HelloWorld"
+}
+
+func (*helloWorldSubresource) ProducesMIMETypes(verb string) []string {
+	return []string{"application/json"}
+}
+
+func (*helloWorldSubresource) ProducesObject(verb string) any {
+	return &v0alpha1.HelloWorld{}
+}
+
+func (*helloWorldSubresource) ConnectMethods() []string {
+	return []string{http.MethodGet}
+}
+
+func (*helloWorldSubresource) NewConnectOptions() (runtime.Object, bool, string) {
+	return nil, false, ""
+}
+
+func (*helloWorldSubresource) Connect(ctx context.Context, name string, opts runtime.Object, responder rest.Responder) (http.Handler, error) {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		whom := r.URL.Query().Get("whom")
+		if whom == "" {
+			whom = "World"
+		}
+
+		responder.Object(http.StatusTeapot, &v0alpha1.HelloWorld{Whom: whom})
+	}), nil
+}
+
+var (
+	_ rest.Storage              = (*helloWorldSubresource)(nil)
+	_ rest.Connecter            = (*helloWorldSubresource)(nil)
+	_ rest.Scoper               = (*helloWorldSubresource)(nil)
+	_ rest.SingularNameProvider = (*helloWorldSubresource)(nil)
+	_ rest.StorageMetadata      = (*helloWorldSubresource)(nil)
+)

pkg/registry/apis/provisioning/register.go

@@ -15,6 +15,7 @@ import (
 	genericapiserver "k8s.io/apiserver/pkg/server"
 	"k8s.io/kube-openapi/pkg/common"
 	"k8s.io/kube-openapi/pkg/spec3"
+	"k8s.io/kube-openapi/pkg/validation/spec"
 )
 
 var _ builder.APIGroupBuilder = (*ProvisioningAPIBuilder)(nil)
@@ -69,8 +70,11 @@ func (b *ProvisioningAPIBuilder) UpdateAPIGroupInfo(apiGroupInfo *genericapiserv
 		return fmt.Errorf("failed to create repository storage: %w", err)
 	}
 
+	helloWorld := &helloWorldSubresource{}
+
 	storage := map[string]rest.Storage{}
 	storage[v0alpha1.RepositoryResourceInfo.StoragePath()] = repositoryStorage
+	storage[v0alpha1.RepositoryResourceInfo.StoragePath("hello")] = helloWorld
 	apiGroupInfo.VersionedResourcesStorageMap[v0alpha1.VERSION] = storage
 	return nil
 }
@@ -89,9 +93,25 @@ func (b *ProvisioningAPIBuilder) PostProcessOpenAPI(oas *spec3.OpenAPI) (*spec3.
 
 	root := "/apis/" + b.GetGroupVersion().String() + "/"
 	// TODO: we might want to register some extras for subresources here.
+	sub := oas.Paths.Paths[root+"namespaces/{namespace}/repositories/{name}/hello"]
+	if sub != nil && sub.Get != nil {
+		sub.Get.Description = "Get a nice hello :)"
+		sub.Get.Parameters = []*spec3.Parameter{
+			{
+				ParameterProps: spec3.ParameterProps{
+					Name:        "whom",
+					In:          "query",
+					Example:     "World!",
+					Description: "Who should get the nice greeting?",
+					Schema:      spec.StringProperty(),
+					Required:    false,
+				},
+			},
+		}
+	}
 
 	// The root API discovery list
-	sub := oas.Paths.Paths[root]
+	sub = oas.Paths.Paths[root]
 	if sub != nil && sub.Get != nil {
 		sub.Get.Tags = []string{"API Discovery"} // sorts first in the list
 	}