implement a fake client

Author: Mengqi Yu

pkg/client/fake/client.go

@@ -0,0 +1,116 @@
+/*
+Copyright 2018 The Kubernetes Authors.
+
+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,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package fake
+
+import (
+	"context"
+	"encoding/json"
+	"log"
+
+	"k8s.io/apimachinery/pkg/api/meta"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/runtime/schema"
+	"k8s.io/client-go/kubernetes/scheme"
+	"k8s.io/client-go/testing"
+
+	"github.com/kubernetes-sigs/controller-runtime/pkg/client"
+)
+
+type fakeClient struct {
+	tracker testing.ObjectTracker
+}
+
+var _ client.Client = &fakeClient{}
+
+// NewFakeClient creates a new fake client for testing.
+func NewFakeClient(initObjs ...runtime.Object) client.Client {
+	tracker := testing.NewObjectTracker(scheme.Scheme, scheme.Codecs.UniversalDecoder())
+	for _, obj := range initObjs {
+		err := tracker.Add(obj)
+		if err != nil {
+			log.Fatalf("failed to add object: %#v, error: %v", obj, err)
+			return nil
+		}
+	}
+	return &fakeClient{
+		tracker: tracker,
+	}
+}
+
+func (c *fakeClient) Get(ctx context.Context, key client.ObjectKey, obj runtime.Object) error {
+	gvr := getGVRFromObject(obj)
+	o, err := c.tracker.Get(gvr, key.Namespace, key.Name)
+	if err != nil {
+		return err
+	}
+	j, err := json.Marshal(o)
+	if err != nil {
+		return err
+	}
+	decoder := scheme.Codecs.UniversalDeserializer()
+	_, _, err = decoder.Decode(j, nil, obj)
+	return err
+}
+
+func (c *fakeClient) List(ctx context.Context, opts *client.ListOptions, list runtime.Object) error {
+	gvk := opts.Raw.TypeMeta.GroupVersionKind()
+	gvr, _ := meta.UnsafeGuessKindToResource(gvk)
+	o, err := c.tracker.List(gvr, gvk, opts.Namespace)
+	if err != nil {
+		return err
+	}
+	j, err := json.Marshal(o)
+	if err != nil {
+		return err
+	}
+	decoder := scheme.Codecs.UniversalDeserializer()
+	_, _, err = decoder.Decode(j, nil, list)
+	return err
+}
+
+func (c *fakeClient) Create(ctx context.Context, obj runtime.Object) error {
+	gvr := getGVRFromObject(obj)
+	accessor, err := meta.Accessor(obj)
+	if err != nil {
+		return err
+	}
+	return c.tracker.Create(gvr, obj, accessor.GetNamespace())
+}
+
+func (c *fakeClient) Delete(ctx context.Context, obj runtime.Object) error {
+	gvr := getGVRFromObject(obj)
+	accessor, err := meta.Accessor(obj)
+	if err != nil {
+		return err
+	}
+	return c.tracker.Delete(gvr, accessor.GetNamespace(), accessor.GetName())
+}
+
+func (c *fakeClient) Update(ctx context.Context, obj runtime.Object) error {
+	gvr := getGVRFromObject(obj)
+	accessor, err := meta.Accessor(obj)
+	if err != nil {
+		return err
+	}
+	return c.tracker.Update(gvr, obj, accessor.GetNamespace())
+}
+
+func getGVRFromObject(obj runtime.Object) schema.GroupVersionResource {
+	gvk := obj.GetObjectKind().GroupVersionKind()
+	gvr, _ := meta.UnsafeGuessKindToResource(gvk)
+	return gvr
+}