add gcp storage wrappers

pkg/kopialib/storage/gcp.go

@@ -0,0 +1,54 @@
+// Copyright 2024 The Kanister 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 storage
+
+import (
+	"context"
+
+	"github.com/kanisterio/kanister/pkg/kopialib"
+	"github.com/kanisterio/kanister/pkg/utils"
+	"github.com/kopia/kopia/repo/blob"
+	"github.com/kopia/kopia/repo/blob/gcs"
+)
+
+var _ Storage = &gcpStorage{}
+
+type gcpStorage struct {
+	Options *gcs.Options
+	Create  bool
+}
+
+func (g *gcpStorage) Connect() (blob.Storage, error) {
+	return gcs.New(context.Background(), g.Options, g.Create)
+}
+
+func (g *gcpStorage) WithOptions(opts gcs.Options) {
+	g.Options = &opts
+}
+
+func (g *gcpStorage) WithCreate(create bool) {
+	g.Create = create
+}
+
+func (g *gcpStorage) SetOptions(ctx context.Context, options map[string]string) error {
+	g.Options = &gcs.Options{
+		Prefix:                        options[kopialib.PrefixKey],
+		BucketName:                    options[kopialib.BucketKey],
+		ServiceAccountCredentialsFile: options[kopialib.GCPServiceAccountCredentialsFile],
+	}
+
+	g.Options.ReadOnly, _ = utils.GetBoolOrDefault(options[kopialib.GCPReadOnly], false)
+	return nil
+}

pkg/kopialib/storage/storage_interface.go

@@ -40,6 +40,8 @@ func New(storageType StorageType) Storage {
 	switch storageType {
 	case TypeS3:
 		return &s3Storage{}
+	case TypeGCP:
+		return &gcpStorage{}
 	default:
 		return nil
 	}