vendor files

vendor/google.golang.org/grpc/credentials/credentials.go

@@ -0,0 +1,219 @@
+/*
+ *
+ * Copyright 2014 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package credentials implements various credentials supported by gRPC library,
+// which encapsulate all the state needed by a client to authenticate with a
+// server and make various assertions, e.g., about the client's identity, role,
+// or whether it is authorized to make a particular call.
+package credentials // import "google.golang.org/grpc/credentials"
+
+import (
+	"crypto/tls"
+	"crypto/x509"
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"net"
+	"strings"
+
+	"golang.org/x/net/context"
+)
+
+// alpnProtoStr are the specified application level protocols for gRPC.
+var alpnProtoStr = []string{"h2"}
+
+// PerRPCCredentials defines the common interface for the credentials which need to
+// attach security information to every RPC (e.g., oauth2).
+type PerRPCCredentials interface {
+	// GetRequestMetadata gets the current request metadata, refreshing
+	// tokens if required. This should be called by the transport layer on
+	// each request, and the data should be populated in headers or other
+	// context. uri is the URI of the entry point for the request. When
+	// supported by the underlying implementation, ctx can be used for
+	// timeout and cancellation.
+	// TODO(zhaoq): Define the set of the qualified keys instead of leaving
+	// it as an arbitrary string.
+	GetRequestMetadata(ctx context.Context, uri ...string) (map[string]string, error)
+	// RequireTransportSecurity indicates whether the credentials requires
+	// transport security.
+	RequireTransportSecurity() bool
+}
+
+// ProtocolInfo provides information regarding the gRPC wire protocol version,
+// security protocol, security protocol version in use, server name, etc.
+type ProtocolInfo struct {
+	// ProtocolVersion is the gRPC wire protocol version.
+	ProtocolVersion string
+	// SecurityProtocol is the security protocol in use.
+	SecurityProtocol string
+	// SecurityVersion is the security protocol version.
+	SecurityVersion string
+	// ServerName is the user-configured server name.
+	ServerName string
+}
+
+// AuthInfo defines the common interface for the auth information the users are interested in.
+type AuthInfo interface {
+	AuthType() string
+}
+
+// ErrConnDispatched indicates that rawConn has been dispatched out of gRPC
+// and the caller should not close rawConn.
+var ErrConnDispatched = errors.New("credentials: rawConn is dispatched out of gRPC")
+
+// TransportCredentials defines the common interface for all the live gRPC wire
+// protocols and supported transport security protocols (e.g., TLS, SSL).
+type TransportCredentials interface {
+	// ClientHandshake does the authentication handshake specified by the corresponding
+	// authentication protocol on rawConn for clients. It returns the authenticated
+	// connection and the corresponding auth information about the connection.
+	// Implementations must use the provided context to implement timely cancellation.
+	// gRPC will try to reconnect if the error returned is a temporary error
+	// (io.EOF, context.DeadlineExceeded or err.Temporary() == true).
+	// If the returned error is a wrapper error, implementations should make sure that
+	// the error implements Temporary() to have the correct retry behaviors.
+	//
+	// If the returned net.Conn is closed, it MUST close the net.Conn provided.
+	ClientHandshake(context.Context, string, net.Conn) (net.Conn, AuthInfo, error)
+	// ServerHandshake does the authentication handshake for servers. It returns
+	// the authenticated connection and the corresponding auth information about
+	// the connection.
+	//
+	// If the returned net.Conn is closed, it MUST close the net.Conn provided.
+	ServerHandshake(net.Conn) (net.Conn, AuthInfo, error)
+	// Info provides the ProtocolInfo of this TransportCredentials.
+	Info() ProtocolInfo
+	// Clone makes a copy of this TransportCredentials.
+	Clone() TransportCredentials
+	// OverrideServerName overrides the server name used to verify the hostname on the returned certificates from the server.
+	// gRPC internals also use it to override the virtual hosting name if it is set.
+	// It must be called before dialing. Currently, this is only used by grpclb.
+	OverrideServerName(string) error
+}
+
+// TLSInfo contains the auth information for a TLS authenticated connection.
+// It implements the AuthInfo interface.
+type TLSInfo struct {
+	State tls.ConnectionState
+}
+
+// AuthType returns the type of TLSInfo as a string.
+func (t TLSInfo) AuthType() string {
+	return "tls"
+}
+
+// tlsCreds is the credentials required for authenticating a connection using TLS.
+type tlsCreds struct {
+	// TLS configuration
+	config *tls.Config
+}
+
+func (c tlsCreds) Info() ProtocolInfo {
+	return ProtocolInfo{
+		SecurityProtocol: "tls",
+		SecurityVersion:  "1.2",
+		ServerName:       c.config.ServerName,
+	}
+}
+
+func (c *tlsCreds) ClientHandshake(ctx context.Context, authority string, rawConn net.Conn) (_ net.Conn, _ AuthInfo, err error) {
+	// use local cfg to avoid clobbering ServerName if using multiple endpoints
+	cfg := cloneTLSConfig(c.config)
+	if cfg.ServerName == "" {
+		colonPos := strings.LastIndex(authority, ":")
+		if colonPos == -1 {
+			colonPos = len(authority)
+		}
+		cfg.ServerName = authority[:colonPos]
+	}
+	conn := tls.Client(rawConn, cfg)
+	errChannel := make(chan error, 1)
+	go func() {
+		errChannel <- conn.Handshake()
+	}()
+	select {
+	case err := <-errChannel:
+		if err != nil {
+			return nil, nil, err
+		}
+	case <-ctx.Done():
+		return nil, nil, ctx.Err()
+	}
+	return conn, TLSInfo{conn.ConnectionState()}, nil
+}
+
+func (c *tlsCreds) ServerHandshake(rawConn net.Conn) (net.Conn, AuthInfo, error) {
+	conn := tls.Server(rawConn, c.config)
+	if err := conn.Handshake(); err != nil {
+		return nil, nil, err
+	}
+	return conn, TLSInfo{conn.ConnectionState()}, nil
+}
+
+func (c *tlsCreds) Clone() TransportCredentials {
+	return NewTLS(c.config)
+}
+
+func (c *tlsCreds) OverrideServerName(serverNameOverride string) error {
+	c.config.ServerName = serverNameOverride
+	return nil
+}
+
+// NewTLS uses c to construct a TransportCredentials based on TLS.
+func NewTLS(c *tls.Config) TransportCredentials {
+	tc := &tlsCreds{cloneTLSConfig(c)}
+	tc.config.NextProtos = alpnProtoStr
+	return tc
+}
+
+// NewClientTLSFromCert constructs TLS credentials from the input certificate for client.
+// serverNameOverride is for testing only. If set to a non empty string,
+// it will override the virtual host name of authority (e.g. :authority header field) in requests.
+func NewClientTLSFromCert(cp *x509.CertPool, serverNameOverride string) TransportCredentials {
+	return NewTLS(&tls.Config{ServerName: serverNameOverride, RootCAs: cp})
+}
+
+// NewClientTLSFromFile constructs TLS credentials from the input certificate file for client.
+// serverNameOverride is for testing only. If set to a non empty string,
+// it will override the virtual host name of authority (e.g. :authority header field) in requests.
+func NewClientTLSFromFile(certFile, serverNameOverride string) (TransportCredentials, error) {
+	b, err := ioutil.ReadFile(certFile)
+	if err != nil {
+		return nil, err
+	}
+	cp := x509.NewCertPool()
+	if !cp.AppendCertsFromPEM(b) {
+		return nil, fmt.Errorf("credentials: failed to append certificates")
+	}
+	return NewTLS(&tls.Config{ServerName: serverNameOverride, RootCAs: cp}), nil
+}
+
+// NewServerTLSFromCert constructs TLS credentials from the input certificate for server.
+func NewServerTLSFromCert(cert *tls.Certificate) TransportCredentials {
+	return NewTLS(&tls.Config{Certificates: []tls.Certificate{*cert}})
+}
+
+// NewServerTLSFromFile constructs TLS credentials from the input certificate file and key
+// file for server.
+func NewServerTLSFromFile(certFile, keyFile string) (TransportCredentials, error) {
+	cert, err := tls.LoadX509KeyPair(certFile, keyFile)
+	if err != nil {
+		return nil, err
+	}
+	return NewTLS(&tls.Config{Certificates: []tls.Certificate{cert}}), nil
+}

vendor/google.golang.org/grpc/credentials/credentials_test.go

@@ -0,0 +1,206 @@
+/*
+ *
+ * Copyright 2016 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package credentials
+
+import (
+	"crypto/tls"
+	"net"
+	"testing"
+
+	"golang.org/x/net/context"
+	"google.golang.org/grpc/testdata"
+)
+
+func TestTLSOverrideServerName(t *testing.T) {
+	expectedServerName := "server.name"
+	c := NewTLS(nil)
+	c.OverrideServerName(expectedServerName)
+	if c.Info().ServerName != expectedServerName {
+		t.Fatalf("c.Info().ServerName = %v, want %v", c.Info().ServerName, expectedServerName)
+	}
+}
+
+func TestTLSClone(t *testing.T) {
+	expectedServerName := "server.name"
+	c := NewTLS(nil)
+	c.OverrideServerName(expectedServerName)
+	cc := c.Clone()
+	if cc.Info().ServerName != expectedServerName {
+		t.Fatalf("cc.Info().ServerName = %v, want %v", cc.Info().ServerName, expectedServerName)
+	}
+	cc.OverrideServerName("")
+	if c.Info().ServerName != expectedServerName {
+		t.Fatalf("Change in clone should not affect the original, c.Info().ServerName = %v, want %v", c.Info().ServerName, expectedServerName)
+	}
+
+}
+
+type serverHandshake func(net.Conn) (AuthInfo, error)
+
+func TestClientHandshakeReturnsAuthInfo(t *testing.T) {
+	done := make(chan AuthInfo, 1)
+	lis := launchServer(t, tlsServerHandshake, done)
+	defer lis.Close()
+	lisAddr := lis.Addr().String()
+	clientAuthInfo := clientHandle(t, gRPCClientHandshake, lisAddr)
+	// wait until server sends serverAuthInfo or fails.
+	serverAuthInfo, ok := <-done
+	if !ok {
+		t.Fatalf("Error at server-side")
+	}
+	if !compare(clientAuthInfo, serverAuthInfo) {
+		t.Fatalf("c.ClientHandshake(_, %v, _) = %v, want %v.", lisAddr, clientAuthInfo, serverAuthInfo)
+	}
+}
+
+func TestServerHandshakeReturnsAuthInfo(t *testing.T) {
+	done := make(chan AuthInfo, 1)
+	lis := launchServer(t, gRPCServerHandshake, done)
+	defer lis.Close()
+	clientAuthInfo := clientHandle(t, tlsClientHandshake, lis.Addr().String())
+	// wait until server sends serverAuthInfo or fails.
+	serverAuthInfo, ok := <-done
+	if !ok {
+		t.Fatalf("Error at server-side")
+	}
+	if !compare(clientAuthInfo, serverAuthInfo) {
+		t.Fatalf("ServerHandshake(_) = %v, want %v.", serverAuthInfo, clientAuthInfo)
+	}
+}
+
+func TestServerAndClientHandshake(t *testing.T) {
+	done := make(chan AuthInfo, 1)
+	lis := launchServer(t, gRPCServerHandshake, done)
+	defer lis.Close()
+	clientAuthInfo := clientHandle(t, gRPCClientHandshake, lis.Addr().String())
+	// wait until server sends serverAuthInfo or fails.
+	serverAuthInfo, ok := <-done
+	if !ok {
+		t.Fatalf("Error at server-side")
+	}
+	if !compare(clientAuthInfo, serverAuthInfo) {
+		t.Fatalf("AuthInfo returned by server: %v and client: %v aren't same", serverAuthInfo, clientAuthInfo)
+	}
+}
+
+func compare(a1, a2 AuthInfo) bool {
+	if a1.AuthType() != a2.AuthType() {
+		return false
+	}
+	switch a1.AuthType() {
+	case "tls":
+		state1 := a1.(TLSInfo).State
+		state2 := a2.(TLSInfo).State
+		if state1.Version == state2.Version &&
+			state1.HandshakeComplete == state2.HandshakeComplete &&
+			state1.CipherSuite == state2.CipherSuite &&
+			state1.NegotiatedProtocol == state2.NegotiatedProtocol {
+			return true
+		}
+		return false
+	default:
+		return false
+	}
+}
+
+func launchServer(t *testing.T, hs serverHandshake, done chan AuthInfo) net.Listener {
+	lis, err := net.Listen("tcp", "localhost:0")
+	if err != nil {
+		t.Fatalf("Failed to listen: %v", err)
+	}
+	go serverHandle(t, hs, done, lis)
+	return lis
+}
+
+// Is run in a separate goroutine.
+func serverHandle(t *testing.T, hs serverHandshake, done chan AuthInfo, lis net.Listener) {
+	serverRawConn, err := lis.Accept()
+	if err != nil {
+		t.Errorf("Server failed to accept connection: %v", err)
+		close(done)
+		return
+	}
+	serverAuthInfo, err := hs(serverRawConn)
+	if err != nil {
+		t.Errorf("Server failed while handshake. Error: %v", err)
+		serverRawConn.Close()
+		close(done)
+		return
+	}
+	done <- serverAuthInfo
+}
+
+func clientHandle(t *testing.T, hs func(net.Conn, string) (AuthInfo, error), lisAddr string) AuthInfo {
+	conn, err := net.Dial("tcp", lisAddr)
+	if err != nil {
+		t.Fatalf("Client failed to connect to %s. Error: %v", lisAddr, err)
+	}
+	defer conn.Close()
+	clientAuthInfo, err := hs(conn, lisAddr)
+	if err != nil {
+		t.Fatalf("Error on client while handshake. Error: %v", err)
+	}
+	return clientAuthInfo
+}
+
+// Server handshake implementation in gRPC.
+func gRPCServerHandshake(conn net.Conn) (AuthInfo, error) {
+	serverTLS, err := NewServerTLSFromFile(testdata.Path("server1.pem"), testdata.Path("server1.key"))
+	if err != nil {
+		return nil, err
+	}
+	_, serverAuthInfo, err := serverTLS.ServerHandshake(conn)
+	if err != nil {
+		return nil, err
+	}
+	return serverAuthInfo, nil
+}
+
+// Client handshake implementation in gRPC.
+func gRPCClientHandshake(conn net.Conn, lisAddr string) (AuthInfo, error) {
+	clientTLS := NewTLS(&tls.Config{InsecureSkipVerify: true})
+	_, authInfo, err := clientTLS.ClientHandshake(context.Background(), lisAddr, conn)
+	if err != nil {
+		return nil, err
+	}
+	return authInfo, nil
+}
+
+func tlsServerHandshake(conn net.Conn) (AuthInfo, error) {
+	cert, err := tls.LoadX509KeyPair(testdata.Path("server1.pem"), testdata.Path("server1.key"))
+	if err != nil {
+		return nil, err
+	}
+	serverTLSConfig := &tls.Config{Certificates: []tls.Certificate{cert}}
+	serverConn := tls.Server(conn, serverTLSConfig)
+	err = serverConn.Handshake()
+	if err != nil {
+		return nil, err
+	}
+	return TLSInfo{State: serverConn.ConnectionState()}, nil
+}
+
+func tlsClientHandshake(conn net.Conn, _ string) (AuthInfo, error) {
+	clientTLSConfig := &tls.Config{InsecureSkipVerify: true}
+	clientConn := tls.Client(conn, clientTLSConfig)
+	if err := clientConn.Handshake(); err != nil {
+		return nil, err
+	}
+	return TLSInfo{State: clientConn.ConnectionState()}, nil
+}

vendor/google.golang.org/grpc/credentials/credentials_util_go17.go

@@ -0,0 +1,60 @@
+// +build go1.7
+// +build !go1.8
+
+/*
+ *
+ * Copyright 2016 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package credentials
+
+import (
+	"crypto/tls"
+)
+
+// cloneTLSConfig returns a shallow clone of the exported
+// fields of cfg, ignoring the unexported sync.Once, which
+// contains a mutex and must not be copied.
+//
+// If cfg is nil, a new zero tls.Config is returned.
+func cloneTLSConfig(cfg *tls.Config) *tls.Config {
+	if cfg == nil {
+		return &tls.Config{}
+	}
+	return &tls.Config{
+		Rand:                        cfg.Rand,
+		Time:                        cfg.Time,
+		Certificates:                cfg.Certificates,
+		NameToCertificate:           cfg.NameToCertificate,
+		GetCertificate:              cfg.GetCertificate,
+		RootCAs:                     cfg.RootCAs,
+		NextProtos:                  cfg.NextProtos,
+		ServerName:                  cfg.ServerName,
+		ClientAuth:                  cfg.ClientAuth,
+		ClientCAs:                   cfg.ClientCAs,
+		InsecureSkipVerify:          cfg.InsecureSkipVerify,
+		CipherSuites:                cfg.CipherSuites,
+		PreferServerCipherSuites:    cfg.PreferServerCipherSuites,
+		SessionTicketsDisabled:      cfg.SessionTicketsDisabled,
+		SessionTicketKey:            cfg.SessionTicketKey,
+		ClientSessionCache:          cfg.ClientSessionCache,
+		MinVersion:                  cfg.MinVersion,
+		MaxVersion:                  cfg.MaxVersion,
+		CurvePreferences:            cfg.CurvePreferences,
+		DynamicRecordSizingDisabled: cfg.DynamicRecordSizingDisabled,
+		Renegotiation:               cfg.Renegotiation,
+	}
+}

vendor/google.golang.org/grpc/credentials/credentials_util_go18.go

@@ -0,0 +1,38 @@
+// +build go1.8
+
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package credentials
+
+import (
+	"crypto/tls"
+)
+
+// cloneTLSConfig returns a shallow clone of the exported
+// fields of cfg, ignoring the unexported sync.Once, which
+// contains a mutex and must not be copied.
+//
+// If cfg is nil, a new zero tls.Config is returned.
+func cloneTLSConfig(cfg *tls.Config) *tls.Config {
+	if cfg == nil {
+		return &tls.Config{}
+	}
+
+	return cfg.Clone()
+}

vendor/google.golang.org/grpc/credentials/credentials_util_pre_go17.go

@@ -0,0 +1,57 @@
+// +build !go1.7
+
+/*
+ *
+ * Copyright 2016 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package credentials
+
+import (
+	"crypto/tls"
+)
+
+// cloneTLSConfig returns a shallow clone of the exported
+// fields of cfg, ignoring the unexported sync.Once, which
+// contains a mutex and must not be copied.
+//
+// If cfg is nil, a new zero tls.Config is returned.
+func cloneTLSConfig(cfg *tls.Config) *tls.Config {
+	if cfg == nil {
+		return &tls.Config{}
+	}
+	return &tls.Config{
+		Rand:                     cfg.Rand,
+		Time:                     cfg.Time,
+		Certificates:             cfg.Certificates,
+		NameToCertificate:        cfg.NameToCertificate,
+		GetCertificate:           cfg.GetCertificate,
+		RootCAs:                  cfg.RootCAs,
+		NextProtos:               cfg.NextProtos,
+		ServerName:               cfg.ServerName,
+		ClientAuth:               cfg.ClientAuth,
+		ClientCAs:                cfg.ClientCAs,
+		InsecureSkipVerify:       cfg.InsecureSkipVerify,
+		CipherSuites:             cfg.CipherSuites,
+		PreferServerCipherSuites: cfg.PreferServerCipherSuites,
+		SessionTicketsDisabled:   cfg.SessionTicketsDisabled,
+		SessionTicketKey:         cfg.SessionTicketKey,
+		ClientSessionCache:       cfg.ClientSessionCache,
+		MinVersion:               cfg.MinVersion,
+		MaxVersion:               cfg.MaxVersion,
+		CurvePreferences:         cfg.CurvePreferences,
+	}
+}

vendor/google.golang.org/grpc/credentials/oauth/oauth.go

@@ -0,0 +1,173 @@
+/*
+ *
+ * Copyright 2015 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package oauth implements gRPC credentials using OAuth.
+package oauth
+
+import (
+	"fmt"
+	"io/ioutil"
+	"sync"
+
+	"golang.org/x/net/context"
+	"golang.org/x/oauth2"
+	"golang.org/x/oauth2/google"
+	"golang.org/x/oauth2/jwt"
+	"google.golang.org/grpc/credentials"
+)
+
+// TokenSource supplies PerRPCCredentials from an oauth2.TokenSource.
+type TokenSource struct {
+	oauth2.TokenSource
+}
+
+// GetRequestMetadata gets the request metadata as a map from a TokenSource.
+func (ts TokenSource) GetRequestMetadata(ctx context.Context, uri ...string) (map[string]string, error) {
+	token, err := ts.Token()
+	if err != nil {
+		return nil, err
+	}
+	return map[string]string{
+		"authorization": token.Type() + " " + token.AccessToken,
+	}, nil
+}
+
+// RequireTransportSecurity indicates whether the credentials requires transport security.
+func (ts TokenSource) RequireTransportSecurity() bool {
+	return true
+}
+
+type jwtAccess struct {
+	jsonKey []byte
+}
+
+// NewJWTAccessFromFile creates PerRPCCredentials from the given keyFile.
+func NewJWTAccessFromFile(keyFile string) (credentials.PerRPCCredentials, error) {
+	jsonKey, err := ioutil.ReadFile(keyFile)
+	if err != nil {
+		return nil, fmt.Errorf("credentials: failed to read the service account key file: %v", err)
+	}
+	return NewJWTAccessFromKey(jsonKey)
+}
+
+// NewJWTAccessFromKey creates PerRPCCredentials from the given jsonKey.
+func NewJWTAccessFromKey(jsonKey []byte) (credentials.PerRPCCredentials, error) {
+	return jwtAccess{jsonKey}, nil
+}
+
+func (j jwtAccess) GetRequestMetadata(ctx context.Context, uri ...string) (map[string]string, error) {
+	ts, err := google.JWTAccessTokenSourceFromJSON(j.jsonKey, uri[0])
+	if err != nil {
+		return nil, err
+	}
+	token, err := ts.Token()
+	if err != nil {
+		return nil, err
+	}
+	return map[string]string{
+		"authorization": token.Type() + " " + token.AccessToken,
+	}, nil
+}
+
+func (j jwtAccess) RequireTransportSecurity() bool {
+	return true
+}
+
+// oauthAccess supplies PerRPCCredentials from a given token.
+type oauthAccess struct {
+	token oauth2.Token
+}
+
+// NewOauthAccess constructs the PerRPCCredentials using a given token.
+func NewOauthAccess(token *oauth2.Token) credentials.PerRPCCredentials {
+	return oauthAccess{token: *token}
+}
+
+func (oa oauthAccess) GetRequestMetadata(ctx context.Context, uri ...string) (map[string]string, error) {
+	return map[string]string{
+		"authorization": oa.token.Type() + " " + oa.token.AccessToken,
+	}, nil
+}
+
+func (oa oauthAccess) RequireTransportSecurity() bool {
+	return true
+}
+
+// NewComputeEngine constructs the PerRPCCredentials that fetches access tokens from
+// Google Compute Engine (GCE)'s metadata server. It is only valid to use this
+// if your program is running on a GCE instance.
+// TODO(dsymonds): Deprecate and remove this.
+func NewComputeEngine() credentials.PerRPCCredentials {
+	return TokenSource{google.ComputeTokenSource("")}
+}
+
+// serviceAccount represents PerRPCCredentials via JWT signing key.
+type serviceAccount struct {
+	mu     sync.Mutex
+	config *jwt.Config
+	t      *oauth2.Token
+}
+
+func (s *serviceAccount) GetRequestMetadata(ctx context.Context, uri ...string) (map[string]string, error) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if !s.t.Valid() {
+		var err error
+		s.t, err = s.config.TokenSource(ctx).Token()
+		if err != nil {
+			return nil, err
+		}
+	}
+	return map[string]string{
+		"authorization": s.t.Type() + " " + s.t.AccessToken,
+	}, nil
+}
+
+func (s *serviceAccount) RequireTransportSecurity() bool {
+	return true
+}
+
+// NewServiceAccountFromKey constructs the PerRPCCredentials using the JSON key slice
+// from a Google Developers service account.
+func NewServiceAccountFromKey(jsonKey []byte, scope ...string) (credentials.PerRPCCredentials, error) {
+	config, err := google.JWTConfigFromJSON(jsonKey, scope...)
+	if err != nil {
+		return nil, err
+	}
+	return &serviceAccount{config: config}, nil
+}
+
+// NewServiceAccountFromFile constructs the PerRPCCredentials using the JSON key file
+// of a Google Developers service account.
+func NewServiceAccountFromFile(keyFile string, scope ...string) (credentials.PerRPCCredentials, error) {
+	jsonKey, err := ioutil.ReadFile(keyFile)
+	if err != nil {
+		return nil, fmt.Errorf("credentials: failed to read the service account key file: %v", err)
+	}
+	return NewServiceAccountFromKey(jsonKey, scope...)
+}
+
+// NewApplicationDefault returns "Application Default Credentials". For more
+// detail, see https://developers.google.com/accounts/docs/application-default-credentials.
+func NewApplicationDefault(ctx context.Context, scope ...string) (credentials.PerRPCCredentials, error) {
+	t, err := google.DefaultTokenSource(ctx, scope...)
+	if err != nil {
+		return nil, err
+	}
+	return TokenSource{t}, nil
+}