blob/gcsblob: add support for using gRPC (#3616)

Author: vangent

blob/gcsblob/gcsblob.go

@@ -295,7 +295,14 @@ type Options struct {
 	// If your implementation of 'SignBytes' needs a request context, set this instead.
 	MakeSignBytes func(requestCtx context.Context) SignBytesFunc
 
+	// Client provides a *storage.Client to use, instead of constructing one based on
+	// the HTTPClient. When set, you must pass nil as the gcp.HTTPClient to OpenBucket.
+	//
+	// For example, this can be used to create a Bucket backed by a gRPC client.
+	Client *storage.Client
+
 	// ClientOptions are passed when constructing the storage.Client.
+	// Ignored if Client is set.
 	ClientOptions []option.ClientOption
 }
 
@@ -312,12 +319,21 @@ type SignBytesFunc func([]byte) ([]byte, error)
 
 // openBucket returns a GCS Bucket that communicates using the given HTTP client.
 func openBucket(ctx context.Context, client *gcp.HTTPClient, bucketName string, opts *Options) (*bucket, error) {
-	if client == nil {
-		return nil, errors.New("gcsblob.OpenBucket: client is required")
+	if opts == nil {
+		opts = &Options{}
 	}
 	if bucketName == "" {
 		return nil, errors.New("gcsblob.OpenBucket: bucketName is required")
 	}
+	if opts.Client != nil {
+		if client != nil {
+			return nil, errors.New("gcsblob.OpenBucket: client must be nil when providing Options.Client")
+		}
+		return &bucket{name: bucketName, client: opts.Client, opts: opts}, nil
+	}
+	if client == nil {
+		return nil, errors.New("gcsblob.OpenBucket: client is required")
+	}
 
 	// We wrap the provided http.Client to add a Go CDK User-Agent.
 	clientOpts := []option.ClientOption{option.WithHTTPClient(useragent.HTTPClient(&client.Client, "blob"))}
@@ -328,9 +344,6 @@ func openBucket(ctx context.Context, client *gcp.HTTPClient, bucketName string,
 			option.WithHTTPClient(http.DefaultClient),
 		}
 	}
-	if opts == nil {
-		opts = &Options{}
-	}
 	clientOpts = append(clientOpts, opts.ClientOptions...)
 	c, err := storage.NewClient(ctx, clientOpts...)
 	if err != nil {

internal/testing/setup/setup.go

@@ -143,7 +143,7 @@ func NewAWSv2Config(ctx context.Context, t *testing.T, region string, scrubBody
 }
 
 // NewGCPClient creates a new HTTPClient for testing against GCP.
-// NewGCPClient creates a new HTTPClient for testing against GCP.
+//
 // If the test is in --record mode, the client will call out to GCP, and the
 // results are recorded in a replay file.
 // Otherwise, the session reads a replay file and runs the test as a replay,
@@ -174,6 +174,7 @@ func NewGCPClient(ctx context.Context, t *testing.T) (client *gcp.HTTPClient, rt
 }
 
 // NewGCPgRPCConn creates a new connection for testing against GCP via gRPC.
+//
 // If the test is in --record mode, the client will call out to GCP, and the
 // results are recorded in a replay file.
 // Otherwise, the session reads a replay file and runs the test as a replay,