Replace glog with grpclog

This allows projects with forked versions of glog (e.g. CockroachDB) to
use grpc-gateway without a flag collision on the glog flags.

protoc-gen-grpc-gateway/gengateway/generator.go

@@ -33,11 +33,11 @@ func New(reg *descriptor.Registry) gen.Generator {
 		"net/http",
 		"github.com/gengo/grpc-gateway/runtime",
 		"github.com/gengo/grpc-gateway/utilities",
-		"github.com/golang/glog",
 		"github.com/golang/protobuf/proto",
 		"golang.org/x/net/context",
 		"google.golang.org/grpc",
 		"google.golang.org/grpc/codes",
+		"google.golang.org/grpc/grpclog",
 	} {
 		pkg := descriptor.GoPackage{
 			Path: pkgpath,

protoc-gen-grpc-gateway/gengateway/template.go

@@ -137,7 +137,7 @@ func request_{{.Method.Service.GetName}}_{{.Method.GetName}}_{{.Index}}(ctx cont
 	var metadata runtime.ServerMetadata
 	stream, err := client.{{.Method.GetName}}(ctx)
 	if err != nil {
-		glog.Errorf("Failed to start streaming: %v", err)
+		grpclog.Printf("Failed to start streaming: %v", err)
 		return nil, metadata, err
 	}
 	dec := json.NewDecoder(req.Body)
@@ -148,22 +148,22 @@ func request_{{.Method.Service.GetName}}_{{.Method.GetName}}_{{.Index}}(ctx cont
 			break
 		}
 		if err != nil {
-			glog.Errorf("Failed to decode request: %v", err)
+			grpclog.Printf("Failed to decode request: %v", err)
 			return nil, metadata, grpc.Errorf(codes.InvalidArgument, "%v", err)
 		}
 		if err = stream.Send(&protoReq); err != nil {
-			glog.Errorf("Failed to send request: %v", err)
+			grpclog.Printf("Failed to send request: %v", err)
 			return nil, metadata, err
 		}
 	}
 
 	if err := stream.CloseSend(); err != nil {
-		glog.Errorf("Failed to terminate client stream: %v", err)
+		grpclog.Printf("Failed to terminate client stream: %v", err)
 		return nil, metadata, err
 	}
 	header, err := stream.Header()
 	if err != nil {
-		glog.Errorf("Failed to get header from client: %v", err)
+		grpclog.Printf("Failed to get header from client: %v", err)
 		return nil, metadata, err
 	}
 	metadata.HeaderMD = header
@@ -247,14 +247,14 @@ func Register{{$svc.GetName}}HandlerFromEndpoint(ctx context.Context, mux *runti
 	defer func() {
 		if err != nil {
 			if cerr := conn.Close(); cerr != nil {
-				glog.Errorf("Failed to close conn to %s: %v", endpoint, cerr)
+				grpclog.Printf("Failed to close conn to %s: %v", endpoint, cerr)
 			}
 			return
 		}
 		go func() {
 			<-ctx.Done()
 			if cerr := conn.Close(); cerr != nil {
-				glog.Errorf("Failed to close conn to %s: %v", endpoint, cerr)
+				grpclog.Printf("Failed to close conn to %s: %v", endpoint, cerr)
 			}
 		}()
 	}()

runtime/errors.go

@@ -5,10 +5,10 @@ import (
 	"io"
 	"net/http"
 
-	"github.com/golang/glog"
 	"golang.org/x/net/context"
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/grpclog"
 )
 
 // HTTPStatusFromCode converts a gRPC error code into the corresponding HTTP response status.
@@ -50,7 +50,7 @@ func HTTPStatusFromCode(code codes.Code) int {
 		return http.StatusInternalServerError
 	}
 
-	glog.Errorf("Unknown gRPC error code: %v", code)
+	grpclog.Printf("Unknown gRPC error code: %v", code)
 	return http.StatusInternalServerError
 }
 
@@ -84,24 +84,24 @@ func DefaultHTTPError(ctx context.Context, w http.ResponseWriter, _ *http.Reques
 	}
 	buf, merr := json.Marshal(body)
 	if merr != nil {
-		glog.Errorf("Failed to marshal error message %q: %v", body, merr)
+		grpclog.Printf("Failed to marshal error message %q: %v", body, merr)
 		w.WriteHeader(http.StatusInternalServerError)
 		if _, err := io.WriteString(w, fallback); err != nil {
-			glog.Errorf("Failed to write response: %v", err)
+			grpclog.Printf("Failed to write response: %v", err)
 		}
 		return
 	}
 
 	md, ok := ServerMetadataFromContext(ctx)
 	if !ok {
-		glog.Errorf("Failed to extract ServerMetadata from context")
+		grpclog.Printf("Failed to extract ServerMetadata from context")
 	}
 
 	handleForwardResponseServerMetadata(w, md)
 	st := HTTPStatusFromCode(grpc.Code(err))
 	w.WriteHeader(st)
 	if _, err := w.Write(buf); err != nil {
-		glog.Errorf("Failed to write response: %v", err)
+		grpclog.Printf("Failed to write response: %v", err)
 	}
 
 	handleForwardResponseTrailer(w, md)