Implement a kube-apiserver backed storage.Interface

Signed-off-by: Aylei <rayingecho@gmail.com>

pkg/apiserver/storage/apiserver.go

@@ -0,0 +1,65 @@
+// Copyright 2019. PingCAP, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package storage
+
+import (
+	"fmt"
+
+	"k8s.io/apimachinery/pkg/runtime/schema"
+	"k8s.io/apiserver/pkg/registry/generic"
+	"k8s.io/apiserver/pkg/storage/storagebackend/factory"
+	"k8s.io/client-go/rest"
+
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apiserver/pkg/storage"
+	"k8s.io/apiserver/pkg/storage/storagebackend"
+)
+
+// ApiServerRestOptionsFactory produce RestOptions for resources using kube-apiserver as storage
+type ApiServerRestOptionsFactory struct {
+	RestConfig       *rest.Config
+	StorageNamespace string
+	Codec            runtime.Codec
+}
+
+// GetRestOptions fetch a new RestOptions from the factory
+func (f *ApiServerRestOptionsFactory) GetRESTOptions(resource schema.GroupResource) (generic.RESTOptions, error) {
+	opts := generic.RESTOptions{
+		ResourcePrefix:          getResourcePrefix(resource),
+		EnableGarbageCollection: true,
+		StorageConfig:           storagebackend.NewDefaultConfig("", f.Codec),
+		Decorator:               f.newApiServerStorageDecorator(),
+	}
+	return opts, nil
+}
+
+// newApiServerStorage returns a new storage decorator which creates a kube-apiserver backed storage interface
+func (f *ApiServerRestOptionsFactory) newApiServerStorageDecorator() generic.StorageDecorator {
+	return func(
+		config *storagebackend.Config,
+		objectType runtime.Object,
+		resourcePrefix string,
+		keyFunc func(obj runtime.Object) (string, error),
+		newListFunc func() runtime.Object,
+		getAttrsFunc storage.AttrFunc,
+		trigger storage.TriggerPublisherFunc,
+	) (storage.Interface, factory.DestroyFunc) {
+		return NewApiServerStore(f.RestConfig, f.Codec, f.StorageNamespace, objectType, newListFunc)
+	}
+}
+
+// getResourcePrefix return a '/{group}/{kind}' prefix for resource key with '/{group}/{kind}/{ns}/{name}' format
+func getResourcePrefix(resource schema.GroupResource) string {
+	return fmt.Sprintf("/%s/%s", resource.Group, resource.Resource)
+}

pkg/apiserver/storage/key.go

@@ -0,0 +1,116 @@
+// Copyright 2019. PingCAP, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package storage
+
+import (
+	"fmt"
+	"strings"
+
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/labels"
+)
+
+const (
+	labelDomain = "apiserver.pingcap.com"
+)
+
+var (
+	groupLabel     = labelDomain + "/group"
+	kindLabel      = labelDomain + "/kind"
+	namespaceLabel = labelDomain + "/namespace"
+	nameLabel      = labelDomain + "/name"
+)
+
+// objKey is a structured representation of key '/{group}/{kind}/{ns}/{name}'
+type objKey struct {
+	group     string
+	kind      string
+	namespace string
+	name      string
+}
+
+func newObjectKey(key string) *objKey {
+	s := strings.Split(strings.TrimPrefix(key, "/"), "/")
+	if len(s) < 2 {
+		panic("expect a string key in /{group}/{kind}/{ns?}/{name?} format")
+	}
+	k := &objKey{
+		group: s[0],
+		kind:  s[1],
+	}
+	if len(s) > 2 {
+		k.namespace = s[2]
+	}
+	if len(s) > 3 {
+		k.name = s[3]
+	}
+	return k
+}
+
+func (o *objKey) fullName() string {
+	sb := strings.Builder{}
+	sb.WriteString(strings.ReplaceAll(o.group, ".", "-"))
+	sb.WriteRune('-')
+	sb.WriteString(o.kind)
+	if o.namespace != "" {
+		sb.WriteRune('-')
+		sb.WriteString(o.namespace)
+	}
+	if o.name != "" {
+		sb.WriteRune('-')
+		sb.WriteString(o.name)
+	}
+	return sb.String()
+}
+
+func (o *objKey) labelMap() map[string]string {
+	m := map[string]string{
+		groupLabel: o.group,
+		kindLabel:  o.kind,
+	}
+	if o.namespace != "" {
+		m[namespaceLabel] = o.namespace
+	}
+	if o.name != "" {
+		m[nameLabel] = o.name
+	}
+	return m
+}
+
+func (o *objKey) objectMeta() metav1.ObjectMeta {
+	return metav1.ObjectMeta{
+		Name:   o.fullName(),
+		Labels: o.labelMap(),
+	}
+}
+
+func (o *objKey) selector() (labels.Selector, error) {
+	return metav1.LabelSelectorAsSelector(&metav1.LabelSelector{
+		MatchLabels: o.labelMap(),
+	})
+}
+
+func (o *objKey) labelSelectorStr() string {
+	sb := strings.Builder{}
+	sb.WriteString(fmt.Sprintf("%s=%s,%s=%s",
+		groupLabel, o.group,
+		kindLabel, o.kind))
+	if o.namespace != "" {
+		sb.WriteString(fmt.Sprintf(",%s=%s", namespaceLabel, o.namespace))
+	}
+	if o.name != "" {
+		sb.WriteString(fmt.Sprintf(",%s=%s", nameLabel, o.name))
+	}
+	return sb.String()
+}