Make TransportAuthenticator not embed Credentials

clientconn.go

@@ -170,9 +170,9 @@ func WithInsecure() DialOption {
 
 // WithTransportCredentials returns a DialOption which configures a
 // connection level security credentials (e.g., TLS/SSL).
-func WithTransportCredentials(creds credentials.TransportAuthenticator) DialOption {
+func WithTransportCredentials(auth credentials.TransportAuthenticator) DialOption {
 	return func(o *dialOptions) {
-		o.copts.AuthOptions = append(o.copts.AuthOptions, creds)
+		o.copts.Authenticators = append(o.copts.Authenticators, auth)
 	}
 }
 
@@ -180,7 +180,7 @@ func WithTransportCredentials(creds credentials.TransportAuthenticator) DialOpti
 // credentials which will place auth state on each outbound RPC.
 func WithPerRPCCredentials(creds credentials.Credentials) DialOption {
 	return func(o *dialOptions) {
-		o.copts.AuthOptions = append(o.copts.AuthOptions, creds)
+		o.copts.Credentials = append(o.copts.Credentials, creds)
 	}
 }
 
@@ -369,17 +369,14 @@ func (cc *ClientConn) newAddrConn(addr Address, skipWait bool) error {
 		ac.events = trace.NewEventLog("grpc.ClientConn", ac.addr.Addr)
 	}
 	if !ac.dopts.insecure {
-		var ok bool
+		if len(ac.dopts.copts.Authenticators) == 0 {
-		for _, cd := range ac.dopts.copts.AuthOptions {
-			if _, ok = cd.(credentials.TransportAuthenticator); ok {
-				break
-			}
-		}
-		if !ok {
 			return errNoTransportSecurity
 		}
 	} else {
-		for _, cd := range ac.dopts.copts.AuthOptions {
+		if len(ac.dopts.copts.Authenticators) > 0 {
+			return errCredentialsMisuse
+		}
+		for _, cd := range ac.dopts.copts.Credentials {
 			if cd.RequireTransportSecurity() {
 				return errCredentialsMisuse
 			}

clientconn_test.go

@@ -38,6 +38,7 @@ import (
 	"time"
 
 	"google.golang.org/grpc/credentials"
+	"google.golang.org/grpc/credentials/oauth"
 )
 
 const tlsDir = "testdata/"
@@ -67,14 +68,18 @@ func TestTLSDialTimeout(t *testing.T) {
 }
 
 func TestCredentialsMisuse(t *testing.T) {
-	creds, err := credentials.NewClientTLSFromFile(tlsDir+"ca.pem", "x.test.youtube.com")
+	auth, err := credentials.NewClientTLSFromFile(tlsDir+"ca.pem", "x.test.youtube.com")
 	if err != nil {
-		t.Fatalf("Failed to create credentials %v", err)
+		t.Fatalf("Failed to create authenticator %v", err)
 	}
 	// Two conflicting credential configurations
-	if _, err := Dial("Non-Existent.Server:80", WithTransportCredentials(creds), WithTimeout(time.Millisecond), WithBlock(), WithInsecure()); err != errCredentialsMisuse {
+	if _, err := Dial("Non-Existent.Server:80", WithTransportCredentials(auth), WithTimeout(time.Millisecond), WithBlock(), WithInsecure()); err != errCredentialsMisuse {
 		t.Fatalf("Dial(_, _) = _, %v, want _, %v", err, errCredentialsMisuse)
 	}
+	creds, err := oauth.NewJWTAccessFromKey(nil)
+	if err != nil {
+		t.Fatalf("Failed to create credentials %v", err)
+	}
 	// security info on insecure connection
 	if _, err := Dial("Non-Existent.Server:80", WithPerRPCCredentials(creds), WithTimeout(time.Millisecond), WithBlock(), WithInsecure()); err != errCredentialsMisuse {
 		t.Fatalf("Dial(_, _) = _, %v, want _, %v", err, errCredentialsMisuse)

credentials/credentials.go

@@ -100,7 +100,6 @@ type TransportAuthenticator interface {
 	ServerHandshake(rawConn net.Conn) (net.Conn, AuthInfo, error)
 	// Info provides the ProtocolInfo of this TransportAuthenticator.
 	Info() ProtocolInfo
-	Credentials
 }
 
 // TLSInfo contains the auth information for a TLS authenticated connection.
@@ -109,6 +108,7 @@ type TLSInfo struct {
 	State tls.ConnectionState
 }
 
+// AuthType returns the type of TLSInfo as a string.
 func (t TLSInfo) AuthType() string {
 	return "tls"
 }

server.go

@@ -95,7 +95,7 @@ type Server struct {
 }
 
 type options struct {
-	creds                credentials.Credentials
+	auth                 credentials.TransportAuthenticator
 	codec                Codec
 	cp                   Compressor
 	dc                   Decompressor
@@ -138,9 +138,9 @@ func MaxConcurrentStreams(n uint32) ServerOption {
 }
 
 // Creds returns a ServerOption that sets credentials for server connections.
-func Creds(c credentials.Credentials) ServerOption {
+func Creds(c credentials.TransportAuthenticator) ServerOption {
 	return func(o *options) {
-		o.creds = c
+		o.auth = c
 	}
 }
 
@@ -249,11 +249,10 @@ var (
 )
 
 func (s *Server) useTransportAuthenticator(rawConn net.Conn) (net.Conn, credentials.AuthInfo, error) {
-	creds, ok := s.opts.creds.(credentials.TransportAuthenticator)
+	if s.opts.auth == nil {
-	if !ok {
 		return rawConn, nil, nil
 	}
-	return creds.ServerHandshake(rawConn)
+	return s.opts.auth.ServerHandshake(rawConn)
 }
 
 // Serve accepts incoming connections on the listener lis, creating a new

transport/http2_client.go

@@ -88,7 +88,7 @@ type http2Client struct {
 	// The scheme used: https if TLS is on, http otherwise.
 	scheme string
 
-	authCreds []credentials.Credentials
+	creds []credentials.Credentials
 
 	mu            sync.Mutex     // guard the following variables
 	state         transportState // the state of underlying connection
@@ -117,8 +117,7 @@ func newHTTP2Client(addr string, opts *ConnectOptions) (_ ClientTransport, err e
 		return nil, ConnectionErrorf("transport: %v", connErr)
 	}
 	var authInfo credentials.AuthInfo
-	for _, c := range opts.AuthOptions {
+	for _, auth := range opts.Authenticators {
-		if ccreds, ok := c.(credentials.TransportAuthenticator); ok {
 		scheme = "https"
 		// TODO(zhaoq): Now the first TransportAuthenticator is used if there are
 		// multiple ones provided. Revisit this if it is not appropriate. Probably
@@ -127,10 +126,9 @@ func newHTTP2Client(addr string, opts *ConnectOptions) (_ ClientTransport, err e
 		if timeout > 0 {
 			timeout -= time.Since(startT)
 		}
-			conn, authInfo, connErr = ccreds.ClientHandshake(addr, conn, timeout)
+		conn, authInfo, connErr = auth.ClientHandshake(addr, conn, timeout)
 		break
 	}
-	}
 	if connErr != nil {
 		return nil, ConnectionErrorf("transport: %v", connErr)
 	}
@@ -163,7 +161,7 @@ func newHTTP2Client(addr string, opts *ConnectOptions) (_ ClientTransport, err e
 		scheme:          scheme,
 		state:           reachable,
 		activeStreams:   make(map[uint32]*Stream),
-		authCreds:       opts.AuthOptions,
+		creds:           opts.Credentials,
 		maxStreams:      math.MaxInt32,
 		streamSendQuota: defaultWindowSize,
 	}
@@ -248,7 +246,7 @@ func (t *http2Client) NewStream(ctx context.Context, callHdr *CallHdr) (_ *Strea
 	}
 	ctx = peer.NewContext(ctx, pr)
 	authData := make(map[string]string)
-	for _, c := range t.authCreds {
+	for _, c := range t.creds {
 		// Construct URI required to get auth request metadata.
 		var port string
 		if pos := strings.LastIndex(t.target, ":"); pos != -1 {

transport/transport.go

@@ -336,8 +336,10 @@ type ConnectOptions struct {
 	UserAgent string
 	// Dialer specifies how to dial a network address.
 	Dialer func(string, time.Duration) (net.Conn, error)
-	// AuthOptions stores the credentials required to setup a client connection and/or issue RPCs.
+	// Credentials stores the credentials required to issue RPCs.
-	AuthOptions []credentials.Credentials
+	Credentials []credentials.Credentials
+	// Authenticators stores the Authenticators required to setup a client connection.
+	Authenticators []credentials.TransportAuthenticator
 	// Timeout specifies the timeout for dialing a ClientTransport.
 	Timeout time.Duration
 }
@@ -473,7 +475,7 @@ func (e ConnectionError) Error() string {
 	return fmt.Sprintf("connection error: desc = %q", e.Desc)
 }
 
-// Define some common ConnectionErrors.
+// ErrConnClosing indicates that the transport is closing.
 var ErrConnClosing = ConnectionError{Desc: "transport is closing"}
 
 // StreamError is an error that only affects one stream within a connection.