feat(storage): add change default storage class sample

storage/buckets/buckets_test.go

@@ -56,6 +56,30 @@ func TestCreateBucketClassLocation(t *testing.T) {
 	}
 }
 
+func TestStorageClass(t *testing.T) {
+	tc := testutil.SystemTest(t)
+	bucketName := tc.ProjectID + "-storage-buckets-tests"
+
+	ctx := context.Background()
+	client, err := storage.NewClient(ctx)
+	if err != nil {
+		t.Fatalf("storage.NewClient: %v", err)
+	}
+	defer client.Close()
+
+	if err := changeDefaultStorageClass(ioutil.Discard, bucketName); err != nil {
+		t.Errorf("changeDefaultStorageClass: %v", err)
+	}
+	attrs, err := client.Bucket(bucketName).Attrs(ctx)
+	if err != nil {
+		t.Fatalf("Bucket(%q).Attrs: %v", bucketName, err)
+	}
+	got := attrs.StorageClass
+	if want := "COLDLINE"; !strings.Contains(got, want) {
+		t.Errorf("got %q, want %q", got, want)
+	}
+}
+
 func TestListBuckets(t *testing.T) {
 	tc := testutil.SystemTest(t)
 	bucketName := tc.ProjectID + "-storage-buckets-tests"

storage/buckets/change_default_storage_class.go

@@ -0,0 +1,54 @@
+// Copyright 2020 Google LLC
+//
+// 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
+//
+//     https://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 buckets
+
+// [START storage_change_default_storage_class]
+import (
+	"context"
+	"fmt"
+	"io"
+	"time"
+
+	"cloud.google.com/go/storage"
+)
+
+// changeDefaultStorageClass changes the storage class on a bucket.
+func changeDefaultStorageClass(w io.Writer, bucketName string) error {
+	// bucketName := "bucket-name"
+	ctx := context.Background()
+	client, err := storage.NewClient(ctx)
+	if err != nil {
+		return fmt.Errorf("storage.NewClient: %v", err)
+	}
+	defer client.Close()
+
+	ctx, cancel := context.WithTimeout(ctx, time.Second*10)
+	defer cancel()
+
+	bucket := client.Bucket(bucketName)
+	// See the StorageClass documentation for other valid storage classes:
+	// https://cloud.google.com/storage/docs/storage-classes
+	newStorageClass := "COLDLINE"
+	bucketAttrsToUpdate := storage.BucketAttrsToUpdate{
+		StorageClass: newStorageClass,
+	}
+	if _, err := bucket.Update(ctx, bucketAttrsToUpdate); err != nil {
+		return fmt.Errorf("Bucket(%q).Update: %v", bucketName, err)
+	}
+	fmt.Fprintf(w, "Default storage class for bucket %v has been set to %v\n", bucketName, newStorageClass)
+	return nil
+}
+
+// [END storage_change_default_storage_class]