move cluster/gce/gci/credential-provider to test/e2e_node/plugins/gcp-credential-provider

Signed-off-by: Andrew Sy Kim <andrewsy@google.com>

test/e2e_node/plugins/gcp-credential-provider/main.go

@@ -0,0 +1,80 @@
+/*
+Copyright 2022 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 main
+
+import (
+	"encoding/json"
+	"errors"
+	"io"
+	"io/ioutil"
+	"net/http"
+	"os"
+	"time"
+
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/klog/v2"
+	credentialproviderv1alpha1 "k8s.io/kubelet/pkg/apis/credentialprovider/v1alpha1"
+)
+
+const metadataTokenEndpoint = "http://metadata.google.internal./computeMetadata/v1/instance/service-accounts/default/token"
+
+func main() {
+	if err := getCredentials(metadataTokenEndpoint, os.Stdin, os.Stdout); err != nil {
+		klog.Fatalf("failed to get credentials: %v", err)
+	}
+}
+
+func getCredentials(tokenEndpoint string, r io.Reader, w io.Writer) error {
+	provider := &provider{
+		client: &http.Client{
+			Timeout: 10 * time.Second,
+		},
+		tokenEndpoint: tokenEndpoint,
+	}
+
+	data, err := ioutil.ReadAll(r)
+	if err != nil {
+		return err
+	}
+
+	var authRequest credentialproviderv1alpha1.CredentialProviderRequest
+	err = json.Unmarshal(data, &authRequest)
+	if err != nil {
+		return err
+	}
+
+	auth, err := provider.Provide(authRequest.Image)
+	if err != nil {
+		return err
+	}
+
+	response := &credentialproviderv1alpha1.CredentialProviderResponse{
+		TypeMeta: metav1.TypeMeta{
+			Kind:       "CredentialProviderResponse",
+			APIVersion: "credentialprovider.kubelet.k8s.io/v1alpha1",
+		},
+		CacheKeyType: credentialproviderv1alpha1.RegistryPluginCacheKeyType,
+		Auth:         auth,
+	}
+
+	if err := json.NewEncoder(w).Encode(response); err != nil {
+		// The error from json.Marshal is intentionally not included so as to not leak credentials into the logs
+		return errors.New("error marshaling response")
+	}
+
+	return nil
+}