runtime pkg cleanup (#2993)

runtime/context.go

@@ -35,11 +35,9 @@ const metadataHeaderBinarySuffix = "-Bin"
 const xForwardedFor = "X-Forwarded-For"
 const xForwardedHost = "X-Forwarded-Host"
 
-var (
-	// DefaultContextTimeout is used for gRPC call context.WithTimeout whenever a Grpc-Timeout inbound
-	// header isn't present. If the value is 0 the sent `context` will not have a timeout.
-	DefaultContextTimeout = 0 * time.Second
-)
+// DefaultContextTimeout is used for gRPC call context.WithTimeout whenever a Grpc-Timeout inbound
+// header isn't present. If the value is 0 the sent `context` will not have a timeout.
+var DefaultContextTimeout = 0 * time.Second
 
 // malformedHTTPHeaders lists the headers that the gRPC server may reject outright as malformed.
 // See https://github.com/grpc/grpc-go/pull/4803#issuecomment-986093310 for more context.
@@ -106,7 +104,6 @@ func annotateContext(ctx context.Context, mux *ServeMux, req *http.Request, rpcM
 	for _, o := range options {
 		ctx = o(ctx)
 	}
-	var pairs []string
 	timeout := DefaultContextTimeout
 	if tm := req.Header.Get(metadataGrpcTimeout); tm != "" {
 		var err error
@@ -115,7 +112,7 @@ func annotateContext(ctx context.Context, mux *ServeMux, req *http.Request, rpcM
 			return nil, nil, status.Errorf(codes.InvalidArgument, "invalid grpc-timeout: %s", tm)
 		}
 	}
-
+	var pairs []string
 	for key, vals := range req.Header {
 		key = textproto.CanonicalMIMEHeaderKey(key)
 		for _, val := range vals {
@@ -281,8 +278,8 @@ func timeoutUnitToDuration(u uint8) (d time.Duration, ok bool) {
 	case 'n':
 		return time.Nanosecond, true
 	default:
+		return
 	}
-	return
 }
 
 // isPermanentHTTPHeader checks whether hdr belongs to the list of

runtime/errors.go

@@ -70,10 +70,10 @@ func HTTPStatusFromCode(code codes.Code) int {
 		return http.StatusServiceUnavailable
 	case codes.DataLoss:
 		return http.StatusInternalServerError
+	default:
+		grpclog.Infof("Unknown gRPC error code: %v", code)
+		return http.StatusInternalServerError
 	}
-
-	grpclog.Infof("Unknown gRPC error code: %v", code)
-	return http.StatusInternalServerError
 }
 
 // HTTPError uses the mux-configured error handler.

runtime/fieldmask.go

@@ -2,6 +2,7 @@ package runtime
 
 import (
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io"
 	"sort"
@@ -44,7 +45,7 @@ func FieldMaskFromRequestBody(r io.Reader, msg proto.Message) (*field_mask.Field
 			// if the item is an object, then enqueue all of its children
 			for k, v := range m {
 				if item.msg == nil {
-					return nil, fmt.Errorf("JSON structure did not match request type")
+					return nil, errors.New("JSON structure did not match request type")
 				}
 
 				fd := getFieldByName(item.msg.Descriptor().Fields(), k)

runtime/handler.go

@@ -85,12 +85,12 @@ func ForwardResponseStream(ctx context.Context, mux *ServeMux, marshaler Marshal
 			handleForwardResponseStreamError(ctx, wroteHeader, marshaler, w, req, mux, err, delimiter)
 			return
 		}
-		if _, err = w.Write(buf); err != nil {
+		if _, err := w.Write(buf); err != nil {
 			grpclog.Infof("Failed to send response chunk: %v", err)
 			return
 		}
 		wroteHeader = true
-		if _, err = w.Write(delimiter); err != nil {
+		if _, err := w.Write(delimiter); err != nil {
 			grpclog.Infof("Failed to send delimiter chunk: %v", err)
 			return
 		}
@@ -207,16 +207,16 @@ func handleForwardResponseStreamError(ctx context.Context, wroteHeader bool, mar
 		w.Header().Set("Content-Type", marshaler.ContentType(msg))
 		w.WriteHeader(HTTPStatusFromCode(st.Code()))
 	}
-	buf, merr := marshaler.Marshal(msg)
-	if merr != nil {
-		grpclog.Infof("Failed to marshal an error: %v", merr)
+	buf, err := marshaler.Marshal(msg)
+	if err != nil {
+		grpclog.Infof("Failed to marshal an error: %v", err)
 		return
 	}
-	if _, werr := w.Write(buf); werr != nil {
-		grpclog.Infof("Failed to notify error to client: %v", werr)
+	if _, err := w.Write(buf); err != nil {
+		grpclog.Infof("Failed to notify error to client: %v", err)
 		return
 	}
-	if _, derr := w.Write(delimiter); derr != nil {
+	if _, err := w.Write(delimiter); err != nil {
 		grpclog.Infof("Failed to send delimiter chunk: %v", err)
 		return
 	}

runtime/marshal_proto.go

@@ -51,8 +51,7 @@ func (marshaller *ProtoMarshaller) NewEncoder(writer io.Writer) Encoder {
 		if err != nil {
 			return err
 		}
-		_, err = writer.Write(buffer)
-		if err != nil {
+		if _, err := writer.Write(buffer); err != nil {
 			return err
 		}
 

runtime/mux.go

@@ -43,9 +43,7 @@ const (
 	UnescapingModeDefault = UnescapingModeLegacy
 )
 
-var (
-	encodedPathSplitter = regexp.MustCompile("(/|%2F)")
-)
+var encodedPathSplitter = regexp.MustCompile("(/|%2F)")
 
 // A HandlerFunc handles a specific pair of path pattern and HTTP method.
 type HandlerFunc func(w http.ResponseWriter, r *http.Request, pathParams map[string]string)
@@ -106,10 +104,10 @@ type HeaderMatcherFunc func(string) (string, bool)
 // keys (as specified by the IANA) to gRPC context with grpcgateway- prefix. HTTP headers that start with
 // 'Grpc-Metadata-' are mapped to gRPC metadata after removing prefix 'Grpc-Metadata-'.
 func DefaultHeaderMatcher(key string) (string, bool) {
-	key = textproto.CanonicalMIMEHeaderKey(key)
-	if isPermanentHTTPHeader(key) {
+	switch key = textproto.CanonicalMIMEHeaderKey(key); {
+	case isPermanentHTTPHeader(key):
 		return MetadataPrefix + key, true
-	} else if strings.HasPrefix(key, MetadataHeaderPrefix) {
+	case strings.HasPrefix(key, MetadataHeaderPrefix):
 		return key[len(MetadataHeaderPrefix):], true
 	}
 	return "", false