Add grpc.Version string and use it in the UA (#1144)

Author: menghanl

clientconn.go

@@ -310,6 +310,14 @@ func DialContext(ctx context.Context, target string, opts ...DialOption) (conn *
 	for _, opt := range opts {
 		opt(&cc.dopts)
 	}
+
+	grpcUA := "grpc-go/" + Version
+	if cc.dopts.copts.UserAgent != "" {
+		cc.dopts.copts.UserAgent += " " + grpcUA
+	} else {
+		cc.dopts.copts.UserAgent = grpcUA
+	}
+
 	if cc.dopts.timeout > 0 {
 		var cancel context.CancelFunc
 		ctx, cancel = context.WithTimeout(ctx, cc.dopts.timeout)

rpc_util.go

@@ -527,3 +527,6 @@ type ServiceConfig struct {
 // requires a synchronised update of grpc-go and protoc-gen-go. This constant
 // should not be referenced from any other code.
 const SupportPackageIsVersion4 = true
+
+// Version is the current grpc version.
+const Version = "1.3.0-dev"

transport/http2_client.go

@@ -187,10 +187,6 @@ func newHTTP2Client(ctx context.Context, addr TargetInfo, opts ConnectOptions) (
 			return nil, connectionErrorf(temp, err, "transport: %v", err)
 		}
 	}
-	ua := primaryUA
-	if opts.UserAgent != "" {
-		ua = opts.UserAgent + " " + ua
-	}
 	kp := opts.KeepaliveParams
 	// Validate keepalive parameters.
 	if kp.Time == 0 {
@@ -203,7 +199,7 @@ func newHTTP2Client(ctx context.Context, addr TargetInfo, opts ConnectOptions) (
 	t := &http2Client{
 		ctx:        ctx,
 		target:     addr.Addr,
-		userAgent:  ua,
+		userAgent:  opts.UserAgent,
 		md:         addr.Metadata,
 		conn:       conn,
 		remoteAddr: conn.RemoteAddr(),

transport/http_util.go

@@ -52,8 +52,6 @@ import (
 )
 
 const (
-	// The primary user agent
-	primaryUA = "grpc-go/1.0"
 	// http2MaxFrameLen specifies the max length of a HTTP2 frame.
 	http2MaxFrameLen = 16384 // 16KB frame
 	// http://http2.github.io/http2-spec/#SettingValues