credentials/alts: Add ServiceOption for server-side ALTS creation (#2009)

* Move handshaker_service_address flag to binaries

credentials/alts/alts.go

@@ -40,6 +40,9 @@ import (
 )
 
 const (
+	// hypervisorHandshakerServiceAddress represents the default ALTS gRPC
+	// handshaker service address in the hypervisor.
+	hypervisorHandshakerServiceAddress = "metadata.google.internal:8080"
 	// defaultTimeout specifies the server handshake timeout.
 	defaultTimeout = 30.0 * time.Second
 	// The following constants specify the minimum and maximum acceptable
@@ -95,39 +98,71 @@ type ClientOptions struct {
 	// TargetServiceAccounts contains a list of expected target service
 	// accounts.
 	TargetServiceAccounts []string
+	// HandshakerServiceAddress represents the ALTS handshaker gRPC service
+	// address to connect to.
+	HandshakerServiceAddress string
+}
+
+// DefaultClientOptions creates a new ClientOptions object with the default
+// values.
+func DefaultClientOptions() *ClientOptions {
+	return &ClientOptions{
+		HandshakerServiceAddress: hypervisorHandshakerServiceAddress,
+	}
+}
+
+// ServerOptions contains the server-side options of an ALTS channel. These
+// options will be passed to the underlying ALTS handshaker.
+type ServerOptions struct {
+	// HandshakerServiceAddress represents the ALTS handshaker gRPC service
+	// address to connect to.
+	HandshakerServiceAddress string
+}
+
+// DefaultServerOptions creates a new ServerOptions object with the default
+// values.
+func DefaultServerOptions() *ServerOptions {
+	return &ServerOptions{
+		HandshakerServiceAddress: hypervisorHandshakerServiceAddress,
+	}
 }
 
 // altsTC is the credentials required for authenticating a connection using ALTS.
 // It implements credentials.TransportCredentials interface.
 type altsTC struct {
-	info     *credentials.ProtocolInfo
-	hsAddr   string
-	side     core.Side
-	accounts []string
+	info      *credentials.ProtocolInfo
+	hsAddr    string
+	side      core.Side
+	accounts  []string
+	hsAddress string
 }
 
 // NewClientCreds constructs a client-side ALTS TransportCredentials object.
 func NewClientCreds(opts *ClientOptions) credentials.TransportCredentials {
-	return newALTS(core.ClientSide, opts.TargetServiceAccounts)
+	return newALTS(core.ClientSide, opts.TargetServiceAccounts, opts.HandshakerServiceAddress)
 }
 
 // NewServerCreds constructs a server-side ALTS TransportCredentials object.
-func NewServerCreds() credentials.TransportCredentials {
-	return newALTS(core.ServerSide, nil)
+func NewServerCreds(opts *ServerOptions) credentials.TransportCredentials {
+	return newALTS(core.ServerSide, nil, opts.HandshakerServiceAddress)
 }
 
-func newALTS(side core.Side, accounts []string) credentials.TransportCredentials {
+func newALTS(side core.Side, accounts []string, hsAddress string) credentials.TransportCredentials {
 	once.Do(func() {
 		vmOnGCP = isRunningOnGCP()
 	})
 
+	if hsAddress == "" {
+		hsAddress = hypervisorHandshakerServiceAddress
+	}
 	return &altsTC{
 		info: &credentials.ProtocolInfo{
 			SecurityProtocol: "alts",
 			SecurityVersion:  "1.0",
 		},
-		side:     side,
-		accounts: accounts,
+		side:      side,
+		accounts:  accounts,
+		hsAddress: hsAddress,
 	}
 }
 
@@ -138,7 +173,7 @@ func (g *altsTC) ClientHandshake(ctx context.Context, addr string, rawConn net.C
 	}
 
 	// Connecting to ALTS handshaker service.
-	hsConn, err := service.Dial()
+	hsConn, err := service.Dial(g.hsAddress)
 	if err != nil {
 		return nil, nil, err
 	}
@@ -191,7 +226,7 @@ func (g *altsTC) ServerHandshake(rawConn net.Conn) (_ net.Conn, _ credentials.Au
 		return nil, nil, ErrUntrustedPlatform
 	}
 	// Connecting to ALTS handshaker service.
-	hsConn, err := service.Dial()
+	hsConn, err := service.Dial(g.hsAddress)
 	if err != nil {
 		return nil, nil, err
 	}

credentials/alts/alts_test.go

@@ -28,7 +28,7 @@ import (
 func TestInfoServerName(t *testing.T) {
 	// This is not testing any handshaker functionality, so it's fine to only
 	// use NewServerCreds and not NewClientCreds.
-	alts := NewServerCreds()
+	alts := NewServerCreds(DefaultServerOptions())
 	if got, want := alts.Info().ServerName, ""; got != want {
 		t.Fatalf("%v.Info().ServerName = %v, want %v", alts, got, want)
 	}
@@ -38,7 +38,7 @@ func TestOverrideServerName(t *testing.T) {
 	wantServerName := "server.name"
 	// This is not testing any handshaker functionality, so it's fine to only
 	// use NewServerCreds and not NewClientCreds.
-	c := NewServerCreds()
+	c := NewServerCreds(DefaultServerOptions())
 	c.OverrideServerName(wantServerName)
 	if got, want := c.Info().ServerName, wantServerName; got != want {
 		t.Fatalf("c.Info().ServerName = %v, want %v", got, want)
@@ -49,7 +49,7 @@ func TestClone(t *testing.T) {
 	wantServerName := "server.name"
 	// This is not testing any handshaker functionality, so it's fine to only
 	// use NewServerCreds and not NewClientCreds.
-	c := NewServerCreds()
+	c := NewServerCreds(DefaultServerOptions())
 	c.OverrideServerName(wantServerName)
 	cc := c.Clone()
 	if got, want := cc.Info().ServerName, wantServerName; got != want {
@@ -67,7 +67,7 @@ func TestClone(t *testing.T) {
 func TestInfo(t *testing.T) {
 	// This is not testing any handshaker functionality, so it's fine to only
 	// use NewServerCreds and not NewClientCreds.
-	c := NewServerCreds()
+	c := NewServerCreds(DefaultServerOptions())
 	info := c.Info()
 	if got, want := info.ProtocolVersion, ""; got != want {
 		t.Errorf("info.ProtocolVersion=%v, want %v", got, want)

credentials/alts/core/handshaker/service/service.go

@@ -21,16 +21,12 @@
 package service
 
 import (
-	"flag"
 	"sync"
 
 	grpc "google.golang.org/grpc"
 )
 
 var (
-	// hsServiceAddr specifies the default ALTS handshaker service address in
-	// the hypervisor.
-	hsServiceAddr = flag.String("handshaker_service_address", "metadata.google.internal:8080", "ALTS handshaker gRPC service address")
 	// hsConn represents a connection to hypervisor handshaker service.
 	hsConn *grpc.ClientConn
 	mu     sync.Mutex
@@ -42,8 +38,8 @@ type dialer func(target string, opts ...grpc.DialOption) (*grpc.ClientConn, erro
 
 // Dial dials the handshake service in the hypervisor. If a connection has
 // already been established, this function returns it. Otherwise, a new
-// connection is created,
-func Dial() (*grpc.ClientConn, error) {
+// connection is created.
+func Dial(hsAddress string) (*grpc.ClientConn, error) {
 	mu.Lock()
 	defer mu.Unlock()
 
@@ -51,7 +47,7 @@ func Dial() (*grpc.ClientConn, error) {
 		// Create a new connection to the handshaker service. Note that
 		// this connection stays open until the application is closed.
 		var err error
-		hsConn, err = hsDialer(*hsServiceAddr, grpc.WithInsecure())
+		hsConn, err = hsDialer(hsAddress, grpc.WithInsecure())
 		if err != nil {
 			return nil, err
 		}

credentials/alts/core/handshaker/service/service_test.go

@@ -24,6 +24,11 @@ import (
 	grpc "google.golang.org/grpc"
 )
 
+const (
+	// The address is irrelevant in this test.
+	testAddress = "some_address"
+)
+
 func TestDial(t *testing.T) {
 	defer func() func() {
 		temp := hsDialer
@@ -39,24 +44,24 @@ func TestDial(t *testing.T) {
 	hsConn = nil
 
 	// First call to Dial, it should create set hsConn.
-	conn1, err := Dial()
+	conn1, err := Dial(testAddress)
 	if err != nil {
 		t.Fatalf("first call to Dial failed: %v", err)
 	}
 	if conn1 == nil {
-		t.Fatal("first call to Dial()=(nil, _), want not nil")
+		t.Fatal("first call to Dial(_)=(nil, _), want not nil")
 	}
 	if got, want := hsConn, conn1; got != want {
 		t.Fatalf("hsConn=%v, want %v", got, want)
 	}
 
-	// Second call to Dial() should return conn1 above.
-	conn2, err := Dial()
+	// Second call to Dial should return conn1 above.
+	conn2, err := Dial(testAddress)
 	if err != nil {
-		t.Fatalf("second call to Dial() failed: %v", err)
+		t.Fatalf("second call to Dial(_) failed: %v", err)
 	}
 	if got, want := conn2, conn1; got != want {
-		t.Fatalf("second call to Dial()=(%v, _), want (%v,. _)", got, want)
+		t.Fatalf("second call to Dial(_)=(%v, _), want (%v,. _)", got, want)
 	}
 	if got, want := hsConn, conn1; got != want {
 		t.Fatalf("hsConn=%v, want %v", got, want)

interop/alts/client/client.go

@@ -35,13 +35,18 @@ const (
 )
 
 var (
+	hsAddr     = flag.String("alts_handshaker_service_address", "", "ALTS handshaker gRPC service address")
 	serverAddr = flag.String("server_address", ":8080", "The port on which the server is listening")
 )
 
 func main() {
 	flag.Parse()
 
-	altsTC := alts.NewClientCreds(&alts.ClientOptions{})
+	opts := alts.DefaultClientOptions()
+	if *hsAddr != "" {
+		opts.HandshakerServiceAddress = *hsAddr
+	}
+	altsTC := alts.NewClientCreds(opts)
 	// Block until the server is ready.
 	conn, err := grpc.Dial(*serverAddr, grpc.WithTransportCredentials(altsTC), grpc.WithBlock())
 	if err != nil {

interop/alts/server/server.go

@@ -31,6 +31,7 @@ import (
 )
 
 var (
+	hsAddr     = flag.String("alts_handshaker_service_address", "", "ALTS handshaker gRPC service address")
 	serverAddr = flag.String("server_address", ":8080", "The port on which the server is listening")
 )
 
@@ -41,7 +42,11 @@ func main() {
 	if err != nil {
 		grpclog.Fatalf("gRPC Server: failed to start the server at %v: %v", *serverAddr, err)
 	}
-	altsTC := alts.NewServerCreds()
+	opts := alts.DefaultServerOptions()
+	if *hsAddr != "" {
+		opts.HandshakerServiceAddress = *hsAddr
+	}
+	altsTC := alts.NewServerCreds(opts)
 	grpcServer := grpc.NewServer(grpc.Creds(altsTC))
 	testpb.RegisterTestServiceServer(grpcServer, interop.NewTestServer())
 	grpcServer.Serve(lis)

interop/client/client.go

@@ -37,6 +37,7 @@ var (
 	caFile                = flag.String("ca_file", "", "The file containning the CA root cert file")
 	useTLS                = flag.Bool("use_tls", false, "Connection uses TLS if true")
 	useALTS               = flag.Bool("use_alts", false, "Connection uses ALTS if true (this option can only be used on GCP)")
+	altsHSAddr            = flag.String("alts_handshaker_service_address", "", "ALTS handshaker gRPC service address")
 	testCA                = flag.Bool("use_test_ca", false, "Whether to replace platform root CAs with test CA as the CA root")
 	serviceAccountKeyFile = flag.String("service_account_key_file", "", "Path to service account json key file")
 	oauthScope            = flag.String("oauth_scope", "", "The scope for OAuth2 tokens")
@@ -110,7 +111,11 @@ func main() {
 			opts = append(opts, grpc.WithPerRPCCredentials(oauth.NewOauthAccess(interop.GetToken(*serviceAccountKeyFile, *oauthScope))))
 		}
 	} else if *useALTS {
-		altsTC := alts.NewClientCreds(&alts.ClientOptions{})
+		altsOpts := alts.DefaultClientOptions()
+		if *altsHSAddr != "" {
+			altsOpts.HandshakerServiceAddress = *altsHSAddr
+		}
+		altsTC := alts.NewClientCreds(altsOpts)
 		opts = append(opts, grpc.WithTransportCredentials(altsTC))
 	} else {
 		opts = append(opts, grpc.WithInsecure())

interop/server/server.go

@@ -33,11 +33,12 @@ import (
 )
 
 var (
-	useTLS   = flag.Bool("use_tls", false, "Connection uses TLS if true, else plain TCP")
-	useALTS  = flag.Bool("use_alts", false, "Connection uses ALTS if true (this option can only be used on GCP)")
-	certFile = flag.String("tls_cert_file", "", "The TLS cert file")
-	keyFile  = flag.String("tls_key_file", "", "The TLS key file")
-	port     = flag.Int("port", 10000, "The server port")
+	useTLS     = flag.Bool("use_tls", false, "Connection uses TLS if true, else plain TCP")
+	useALTS    = flag.Bool("use_alts", false, "Connection uses ALTS if true (this option can only be used on GCP)")
+	altsHSAddr = flag.String("alts_handshaker_service_address", "", "ALTS handshaker gRPC service address")
+	certFile   = flag.String("tls_cert_file", "", "The TLS cert file")
+	keyFile    = flag.String("tls_key_file", "", "The TLS key file")
+	port       = flag.Int("port", 10000, "The server port")
 )
 
 func main() {
@@ -64,7 +65,11 @@ func main() {
 		}
 		opts = append(opts, grpc.Creds(creds))
 	} else if *useALTS {
-		altsTC := alts.NewServerCreds()
+		altsOpts := alts.DefaultServerOptions()
+		if *altsHSAddr != "" {
+			altsOpts.HandshakerServiceAddress = *altsHSAddr
+		}
+		altsTC := alts.NewServerCreds(altsOpts)
 		opts = append(opts, grpc.Creds(altsTC))
 	}
 	server := grpc.NewServer(opts...)