Enable using gRPC client for GCS

GCP has an experimental feature which allows using gRPC when talking to GCS.
For the time being, it requires buckets to be explicitly added to an allowlist,
but eventually the feature will become GA.

This commit allows using a gRPC client when creating a GCS bucket by toggling
a boolean flag in the bucket config.

Signed-off-by: Filip Petkovski <[email protected]>

providers/gcs/gcs.go

@@ -33,6 +33,7 @@ const DirDelim = "/"
 type Config struct {
 	Bucket         string `yaml:"bucket"`
 	ServiceAccount string `yaml:"service_account"`
+	UseGRPC        bool   `yaml:"use_grpc"`
 }
 
 // Bucket implements the store.Bucket and shipper.Bucket interfaces against GCS.
@@ -75,7 +76,19 @@ func NewBucketWithConfig(ctx context.Context, logger log.Logger, gc Config, comp
 		option.WithUserAgent(fmt.Sprintf("thanos-%s/%s (%s)", component, version.Version, runtime.Version())),
 	)
 
-	gcsClient, err := storage.NewClient(ctx, opts...)
+	return newBucket(ctx, logger, gc, opts)
+}
+
+func newBucket(ctx context.Context, logger log.Logger, gc Config, opts []option.ClientOption) (*Bucket, error) {
+	var (
+		err       error
+		gcsClient *storage.Client
+	)
+	if gc.UseGRPC {
+		gcsClient, err = storage.NewGRPCClient(ctx, opts...)
+	} else {
+		gcsClient, err = storage.NewClient(ctx, opts...)
+	}
 	if err != nil {
 		return nil, err
 	}