migrate gplus to google oauth2 provider (#7885)

* migrate gplus to google oauth2 provider. this still provides support for old gplus connections.

* Update models/oauth2.go

Co-Authored-By: Antoine GIRARD <sapk@users.noreply.github.com>

* make vendor

go.mod

@@ -68,8 +68,8 @@ require (
 	github.com/lib/pq v1.2.0
 	github.com/lunny/dingtalk_webhook v0.0.0-20171025031554-e3534c89ef96
 	github.com/lunny/levelqueue v0.0.0-20190217115915-02b525a4418e
-	github.com/markbates/goth v1.56.0
 	github.com/mailru/easyjson v0.7.0 // indirect
+	github.com/markbates/goth v1.56.0
 	github.com/mattn/go-isatty v0.0.7
 	github.com/mattn/go-oci8 v0.0.0-20190320171441-14ba190cf52d // indirect
 	github.com/mattn/go-sqlite3 v1.11.0

models/oauth2.go

@@ -40,7 +40,7 @@ var OAuth2Providers = map[string]OAuth2Provider{
 			ProfileURL: oauth2.GetDefaultProfileURL("gitlab"),
 		},
 	},
-	"gplus":         {Name: "gplus", DisplayName: "Google+", Image: "/img/auth/google_plus.png"},
+	"gplus":         {Name: "gplus", DisplayName: "Google", Image: "/img/auth/google.png"},
 	"openidConnect": {Name: "openidConnect", DisplayName: "OpenID Connect", Image: "/img/auth/openid_connect.png"},
 	"twitter":       {Name: "twitter", DisplayName: "Twitter", Image: "/img/auth/twitter.png"},
 	"discord":       {Name: "discord", DisplayName: "Discord", Image: "/img/auth/discord.png"},

modules/auth/oauth2/oauth2.go

@@ -22,7 +22,7 @@ import (
 	"github.com/markbates/goth/providers/gitea"
 	"github.com/markbates/goth/providers/github"
 	"github.com/markbates/goth/providers/gitlab"
-	"github.com/markbates/goth/providers/gplus"
+	"github.com/markbates/goth/providers/google"
 	"github.com/markbates/goth/providers/openidConnect"
 	"github.com/markbates/goth/providers/twitter"
 	"github.com/satori/go.uuid"
@@ -166,8 +166,8 @@ func createProvider(providerName, providerType, clientID, clientSecret, openIDCo
 			}
 		}
 		provider = gitlab.NewCustomisedURL(clientID, clientSecret, callbackURL, authURL, tokenURL, profileURL, "read_user")
-	case "gplus":
-		provider = gplus.New(clientID, clientSecret, callbackURL, "email")
+	case "gplus": // named gplus due to legacy gplus -> google migration (Google killed Google+). This ensures old connections still work
+		provider = google.New(clientID, clientSecret, callbackURL)
 	case "openidConnect":
 		if provider, err = openidConnect.New(clientID, clientSecret, callbackURL, openIDConnectAutoDiscoveryURL); err != nil {
 			log.Warn("Failed to create OpenID Connect Provider with name '%s' with url '%s': %v", providerName, openIDConnectAutoDiscoveryURL, err)

templates/admin/auth/new.tmpl

@@ -102,7 +102,7 @@
 				<span>{{.i18n.Tr "admin.auths.tip.github"}}</span>
 				<li>GitLab</li>
 				<span>{{.i18n.Tr "admin.auths.tip.gitlab"}}</span>
-				<li>Google+</li>
+				<li>Google</li>
 				<span>{{.i18n.Tr "admin.auths.tip.google_plus"}}</span>
 				<li>OpenID Connect</li>
 				<span>{{.i18n.Tr "admin.auths.tip.openid_connect"}}</span>

vendor/cloud.google.com/go/compute/metadata/metadata.go

@@ -0,0 +1,526 @@
+// Copyright 2014 Google LLC
+//
+// 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 metadata provides access to Google Compute Engine (GCE)
+// metadata and API service accounts.
+//
+// This package is a wrapper around the GCE metadata service,
+// as documented at https://developers.google.com/compute/docs/metadata.
+package metadata // import "cloud.google.com/go/compute/metadata"
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"net"
+	"net/http"
+	"net/url"
+	"os"
+	"runtime"
+	"strings"
+	"sync"
+	"time"
+)
+
+const (
+	// metadataIP is the documented metadata server IP address.
+	metadataIP = "169.254.169.254"
+
+	// metadataHostEnv is the environment variable specifying the
+	// GCE metadata hostname.  If empty, the default value of
+	// metadataIP ("169.254.169.254") is used instead.
+	// This is variable name is not defined by any spec, as far as
+	// I know; it was made up for the Go package.
+	metadataHostEnv = "GCE_METADATA_HOST"
+
+	userAgent = "gcloud-golang/0.1"
+)
+
+type cachedValue struct {
+	k    string
+	trim bool
+	mu   sync.Mutex
+	v    string
+}
+
+var (
+	projID  = &cachedValue{k: "project/project-id", trim: true}
+	projNum = &cachedValue{k: "project/numeric-project-id", trim: true}
+	instID  = &cachedValue{k: "instance/id", trim: true}
+)
+
+var (
+	defaultClient = &Client{hc: &http.Client{
+		Transport: &http.Transport{
+			Dial: (&net.Dialer{
+				Timeout:   2 * time.Second,
+				KeepAlive: 30 * time.Second,
+			}).Dial,
+			ResponseHeaderTimeout: 2 * time.Second,
+		},
+	}}
+	subscribeClient = &Client{hc: &http.Client{
+		Transport: &http.Transport{
+			Dial: (&net.Dialer{
+				Timeout:   2 * time.Second,
+				KeepAlive: 30 * time.Second,
+			}).Dial,
+		},
+	}}
+)
+
+// NotDefinedError is returned when requested metadata is not defined.
+//
+// The underlying string is the suffix after "/computeMetadata/v1/".
+//
+// This error is not returned if the value is defined to be the empty
+// string.
+type NotDefinedError string
+
+func (suffix NotDefinedError) Error() string {
+	return fmt.Sprintf("metadata: GCE metadata %q not defined", string(suffix))
+}
+
+func (c *cachedValue) get(cl *Client) (v string, err error) {
+	defer c.mu.Unlock()
+	c.mu.Lock()
+	if c.v != "" {
+		return c.v, nil
+	}
+	if c.trim {
+		v, err = cl.getTrimmed(c.k)
+	} else {
+		v, err = cl.Get(c.k)
+	}
+	if err == nil {
+		c.v = v
+	}
+	return
+}
+
+var (
+	onGCEOnce sync.Once
+	onGCE     bool
+)
+
+// OnGCE reports whether this process is running on Google Compute Engine.
+func OnGCE() bool {
+	onGCEOnce.Do(initOnGCE)
+	return onGCE
+}
+
+func initOnGCE() {
+	onGCE = testOnGCE()
+}
+
+func testOnGCE() bool {
+	// The user explicitly said they're on GCE, so trust them.
+	if os.Getenv(metadataHostEnv) != "" {
+		return true
+	}
+
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	resc := make(chan bool, 2)
+
+	// Try two strategies in parallel.
+	// See https://github.com/googleapis/google-cloud-go/issues/194
+	go func() {
+		req, _ := http.NewRequest("GET", "http://"+metadataIP, nil)
+		req.Header.Set("User-Agent", userAgent)
+		res, err := defaultClient.hc.Do(req.WithContext(ctx))
+		if err != nil {
+			resc <- false
+			return
+		}
+		defer res.Body.Close()
+		resc <- res.Header.Get("Metadata-Flavor") == "Google"
+	}()
+
+	go func() {
+		addrs, err := net.LookupHost("metadata.google.internal")
+		if err != nil || len(addrs) == 0 {
+			resc <- false
+			return
+		}
+		resc <- strsContains(addrs, metadataIP)
+	}()
+
+	tryHarder := systemInfoSuggestsGCE()
+	if tryHarder {
+		res := <-resc
+		if res {
+			// The first strategy succeeded, so let's use it.
+			return true
+		}
+		// Wait for either the DNS or metadata server probe to
+		// contradict the other one and say we are running on
+		// GCE. Give it a lot of time to do so, since the system
+		// info already suggests we're running on a GCE BIOS.
+		timer := time.NewTimer(5 * time.Second)
+		defer timer.Stop()
+		select {
+		case res = <-resc:
+			return res
+		case <-timer.C:
+			// Too slow. Who knows what this system is.
+			return false
+		}
+	}
+
+	// There's no hint from the system info that we're running on
+	// GCE, so use the first probe's result as truth, whether it's
+	// true or false. The goal here is to optimize for speed for
+	// users who are NOT running on GCE. We can't assume that
+	// either a DNS lookup or an HTTP request to a blackholed IP
+	// address is fast. Worst case this should return when the
+	// metaClient's Transport.ResponseHeaderTimeout or
+	// Transport.Dial.Timeout fires (in two seconds).
+	return <-resc
+}
+
+// systemInfoSuggestsGCE reports whether the local system (without
+// doing network requests) suggests that we're running on GCE. If this
+// returns true, testOnGCE tries a bit harder to reach its metadata
+// server.
+func systemInfoSuggestsGCE() bool {
+	if runtime.GOOS != "linux" {
+		// We don't have any non-Linux clues available, at least yet.
+		return false
+	}
+	slurp, _ := ioutil.ReadFile("/sys/class/dmi/id/product_name")
+	name := strings.TrimSpace(string(slurp))
+	return name == "Google" || name == "Google Compute Engine"
+}
+
+// Subscribe calls Client.Subscribe on a client designed for subscribing (one with no
+// ResponseHeaderTimeout).
+func Subscribe(suffix string, fn func(v string, ok bool) error) error {
+	return subscribeClient.Subscribe(suffix, fn)
+}
+
+// Get calls Client.Get on the default client.
+func Get(suffix string) (string, error) { return defaultClient.Get(suffix) }
+
+// ProjectID returns the current instance's project ID string.
+func ProjectID() (string, error) { return defaultClient.ProjectID() }
+
+// NumericProjectID returns the current instance's numeric project ID.
+func NumericProjectID() (string, error) { return defaultClient.NumericProjectID() }
+
+// InternalIP returns the instance's primary internal IP address.
+func InternalIP() (string, error) { return defaultClient.InternalIP() }
+
+// ExternalIP returns the instance's primary external (public) IP address.
+func ExternalIP() (string, error) { return defaultClient.ExternalIP() }
+
+// Email calls Client.Email on the default client.
+func Email(serviceAccount string) (string, error) { return defaultClient.Email(serviceAccount) }
+
+// Hostname returns the instance's hostname. This will be of the form
+// "<instanceID>.c.<projID>.internal".
+func Hostname() (string, error) { return defaultClient.Hostname() }
+
+// InstanceTags returns the list of user-defined instance tags,
+// assigned when initially creating a GCE instance.
+func InstanceTags() ([]string, error) { return defaultClient.InstanceTags() }
+
+// InstanceID returns the current VM's numeric instance ID.
+func InstanceID() (string, error) { return defaultClient.InstanceID() }
+
+// InstanceName returns the current VM's instance ID string.
+func InstanceName() (string, error) { return defaultClient.InstanceName() }
+
+// Zone returns the current VM's zone, such as "us-central1-b".
+func Zone() (string, error) { return defaultClient.Zone() }
+
+// InstanceAttributes calls Client.InstanceAttributes on the default client.
+func InstanceAttributes() ([]string, error) { return defaultClient.InstanceAttributes() }
+
+// ProjectAttributes calls Client.ProjectAttributes on the default client.
+func ProjectAttributes() ([]string, error) { return defaultClient.ProjectAttributes() }
+
+// InstanceAttributeValue calls Client.InstanceAttributeValue on the default client.
+func InstanceAttributeValue(attr string) (string, error) {
+	return defaultClient.InstanceAttributeValue(attr)
+}
+
+// ProjectAttributeValue calls Client.ProjectAttributeValue on the default client.
+func ProjectAttributeValue(attr string) (string, error) {
+	return defaultClient.ProjectAttributeValue(attr)
+}
+
+// Scopes calls Client.Scopes on the default client.
+func Scopes(serviceAccount string) ([]string, error) { return defaultClient.Scopes(serviceAccount) }
+
+func strsContains(ss []string, s string) bool {
+	for _, v := range ss {
+		if v == s {
+			return true
+		}
+	}
+	return false
+}
+
+// A Client provides metadata.
+type Client struct {
+	hc *http.Client
+}
+
+// NewClient returns a Client that can be used to fetch metadata. All HTTP requests
+// will use the given http.Client instead of the default client.
+func NewClient(c *http.Client) *Client {
+	return &Client{hc: c}
+}
+
+// getETag returns a value from the metadata service as well as the associated ETag.
+// This func is otherwise equivalent to Get.
+func (c *Client) getETag(suffix string) (value, etag string, err error) {
+	// Using a fixed IP makes it very difficult to spoof the metadata service in
+	// a container, which is an important use-case for local testing of cloud
+	// deployments. To enable spoofing of the metadata service, the environment
+	// variable GCE_METADATA_HOST is first inspected to decide where metadata
+	// requests shall go.
+	host := os.Getenv(metadataHostEnv)
+	if host == "" {
+		// Using 169.254.169.254 instead of "metadata" here because Go
+		// binaries built with the "netgo" tag and without cgo won't
+		// know the search suffix for "metadata" is
+		// ".google.internal", and this IP address is documented as
+		// being stable anyway.
+		host = metadataIP
+	}
+	u := "http://" + host + "/computeMetadata/v1/" + suffix
+	req, _ := http.NewRequest("GET", u, nil)
+	req.Header.Set("Metadata-Flavor", "Google")
+	req.Header.Set("User-Agent", userAgent)
+	res, err := c.hc.Do(req)
+	if err != nil {
+		return "", "", err
+	}
+	defer res.Body.Close()
+	if res.StatusCode == http.StatusNotFound {
+		return "", "", NotDefinedError(suffix)
+	}
+	all, err := ioutil.ReadAll(res.Body)
+	if err != nil {
+		return "", "", err
+	}
+	if res.StatusCode != 200 {
+		return "", "", &Error{Code: res.StatusCode, Message: string(all)}
+	}
+	return string(all), res.Header.Get("Etag"), nil
+}
+
+// Get returns a value from the metadata service.
+// The suffix is appended to "http://${GCE_METADATA_HOST}/computeMetadata/v1/".
+//
+// If the GCE_METADATA_HOST environment variable is not defined, a default of
+// 169.254.169.254 will be used instead.
+//
+// If the requested metadata is not defined, the returned error will
+// be of type NotDefinedError.
+func (c *Client) Get(suffix string) (string, error) {
+	val, _, err := c.getETag(suffix)
+	return val, err
+}
+
+func (c *Client) getTrimmed(suffix string) (s string, err error) {
+	s, err = c.Get(suffix)
+	s = strings.TrimSpace(s)
+	return
+}
+
+func (c *Client) lines(suffix string) ([]string, error) {
+	j, err := c.Get(suffix)
+	if err != nil {
+		return nil, err
+	}
+	s := strings.Split(strings.TrimSpace(j), "\n")
+	for i := range s {
+		s[i] = strings.TrimSpace(s[i])
+	}
+	return s, nil
+}
+
+// ProjectID returns the current instance's project ID string.
+func (c *Client) ProjectID() (string, error) { return projID.get(c) }
+
+// NumericProjectID returns the current instance's numeric project ID.
+func (c *Client) NumericProjectID() (string, error) { return projNum.get(c) }
+
+// InstanceID returns the current VM's numeric instance ID.
+func (c *Client) InstanceID() (string, error) { return instID.get(c) }
+
+// InternalIP returns the instance's primary internal IP address.
+func (c *Client) InternalIP() (string, error) {
+	return c.getTrimmed("instance/network-interfaces/0/ip")
+}
+
+// Email returns the email address associated with the service account.
+// The account may be empty or the string "default" to use the instance's
+// main account.
+func (c *Client) Email(serviceAccount string) (string, error) {
+	if serviceAccount == "" {
+		serviceAccount = "default"
+	}
+	return c.getTrimmed("instance/service-accounts/" + serviceAccount + "/email")
+}
+
+// ExternalIP returns the instance's primary external (public) IP address.
+func (c *Client) ExternalIP() (string, error) {
+	return c.getTrimmed("instance/network-interfaces/0/access-configs/0/external-ip")
+}
+
+// Hostname returns the instance's hostname. This will be of the form
+// "<instanceID>.c.<projID>.internal".
+func (c *Client) Hostname() (string, error) {
+	return c.getTrimmed("instance/hostname")
+}
+
+// InstanceTags returns the list of user-defined instance tags,
+// assigned when initially creating a GCE instance.
+func (c *Client) InstanceTags() ([]string, error) {
+	var s []string
+	j, err := c.Get("instance/tags")
+	if err != nil {
+		return nil, err
+	}
+	if err := json.NewDecoder(strings.NewReader(j)).Decode(&s); err != nil {
+		return nil, err
+	}
+	return s, nil
+}
+
+// InstanceName returns the current VM's instance ID string.
+func (c *Client) InstanceName() (string, error) {
+	host, err := c.Hostname()
+	if err != nil {
+		return "", err
+	}
+	return strings.Split(host, ".")[0], nil
+}
+
+// Zone returns the current VM's zone, such as "us-central1-b".
+func (c *Client) Zone() (string, error) {
+	zone, err := c.getTrimmed("instance/zone")
+	// zone is of the form "projects/<projNum>/zones/<zoneName>".
+	if err != nil {
+		return "", err
+	}
+	return zone[strings.LastIndex(zone, "/")+1:], nil
+}
+
+// InstanceAttributes returns the list of user-defined attributes,
+// assigned when initially creating a GCE VM instance. The value of an
+// attribute can be obtained with InstanceAttributeValue.
+func (c *Client) InstanceAttributes() ([]string, error) { return c.lines("instance/attributes/") }
+
+// ProjectAttributes returns the list of user-defined attributes
+// applying to the project as a whole, not just this VM.  The value of
+// an attribute can be obtained with ProjectAttributeValue.
+func (c *Client) ProjectAttributes() ([]string, error) { return c.lines("project/attributes/") }
+
+// InstanceAttributeValue returns the value of the provided VM
+// instance attribute.
+//
+// If the requested attribute is not defined, the returned error will
+// be of type NotDefinedError.
+//
+// InstanceAttributeValue may return ("", nil) if the attribute was
+// defined to be the empty string.
+func (c *Client) InstanceAttributeValue(attr string) (string, error) {
+	return c.Get("instance/attributes/" + attr)
+}
+
+// ProjectAttributeValue returns the value of the provided
+// project attribute.
+//
+// If the requested attribute is not defined, the returned error will
+// be of type NotDefinedError.
+//
+// ProjectAttributeValue may return ("", nil) if the attribute was
+// defined to be the empty string.
+func (c *Client) ProjectAttributeValue(attr string) (string, error) {
+	return c.Get("project/attributes/" + attr)
+}
+
+// Scopes returns the service account scopes for the given account.
+// The account may be empty or the string "default" to use the instance's
+// main account.
+func (c *Client) Scopes(serviceAccount string) ([]string, error) {
+	if serviceAccount == "" {
+		serviceAccount = "default"
+	}
+	return c.lines("instance/service-accounts/" + serviceAccount + "/scopes")
+}
+
+// Subscribe subscribes to a value from the metadata service.
+// The suffix is appended to "http://${GCE_METADATA_HOST}/computeMetadata/v1/".
+// The suffix may contain query parameters.
+//
+// Subscribe calls fn with the latest metadata value indicated by the provided
+// suffix. If the metadata value is deleted, fn is called with the empty string
+// and ok false. Subscribe blocks until fn returns a non-nil error or the value
+// is deleted. Subscribe returns the error value returned from the last call to
+// fn, which may be nil when ok == false.
+func (c *Client) Subscribe(suffix string, fn func(v string, ok bool) error) error {
+	const failedSubscribeSleep = time.Second * 5
+
+	// First check to see if the metadata value exists at all.
+	val, lastETag, err := c.getETag(suffix)
+	if err != nil {
+		return err
+	}
+
+	if err := fn(val, true); err != nil {
+		return err
+	}
+
+	ok := true
+	if strings.ContainsRune(suffix, '?') {
+		suffix += "&wait_for_change=true&last_etag="
+	} else {
+		suffix += "?wait_for_change=true&last_etag="
+	}
+	for {
+		val, etag, err := c.getETag(suffix + url.QueryEscape(lastETag))
+		if err != nil {
+			if _, deleted := err.(NotDefinedError); !deleted {
+				time.Sleep(failedSubscribeSleep)
+				continue // Retry on other errors.
+			}
+			ok = false
+		}
+		lastETag = etag
+
+		if err := fn(val, ok); err != nil || !ok {
+			return err
+		}
+	}
+}
+
+// Error contains an error response from the server.
+type Error struct {
+	// Code is the HTTP response status code.
+	Code int
+	// Message is the server response message.
+	Message string
+}
+
+func (e *Error) Error() string {
+	return fmt.Sprintf("compute: Received %d `%s`", e.Code, e.Message)
+}

vendor/github.com/markbates/goth/providers/google/endpoint.go

@@ -0,0 +1,10 @@
+// +build go1.9
+
+package google
+
+import (
+	goog "golang.org/x/oauth2/google"
+)
+
+// Endpoint is Google's OAuth 2.0 endpoint.
+var Endpoint = goog.Endpoint

vendor/github.com/markbates/goth/providers/google/endpoint_legacy.go

@@ -0,0 +1,13 @@
+// +build !go1.9
+
+package google
+
+import (
+	"golang.org/x/oauth2"
+)
+
+// Endpoint is Google's OAuth 2.0 endpoint.
+var Endpoint = oauth2.Endpoint{
+	AuthURL:  "https://accounts.google.com/o/oauth2/auth",
+	TokenURL: "https://accounts.google.com/o/oauth2/token",
+}

vendor/github.com/markbates/goth/providers/google/google.go

@@ -1,42 +1,36 @@
-// Package gplus implements the OAuth2 protocol for authenticating users through Google+.
-// This package can be used as a reference implementation of an OAuth2 provider for Goth.
-package gplus
+// Package google implements the OAuth2 protocol for authenticating users
+// through Google.
+package google
 
 import (
-	"bytes"
 	"encoding/json"
-	"io"
+	"fmt"
 	"io/ioutil"
 	"net/http"
 	"net/url"
 	"strings"
 
-	"fmt"
 	"github.com/markbates/goth"
 	"golang.org/x/oauth2"
 )
 
-const (
-	authURL         string = "https://accounts.google.com/o/oauth2/auth?access_type=offline"
-	tokenURL        string = "https://accounts.google.com/o/oauth2/token"
-	endpointProfile string = "https://www.googleapis.com/oauth2/v2/userinfo"
-)
+const endpointProfile string = "https://www.googleapis.com/oauth2/v2/userinfo"
 
-// New creates a new Google+ provider, and sets up important connection details.
-// You should always call `gplus.New` to get a new Provider. Never try to create
+// New creates a new Google provider, and sets up important connection details.
+// You should always call `google.New` to get a new Provider. Never try to create
 // one manually.
 func New(clientKey, secret, callbackURL string, scopes ...string) *Provider {
 	p := &Provider{
 		ClientKey:    clientKey,
 		Secret:       secret,
 		CallbackURL:  callbackURL,
-		providerName: "gplus",
+		providerName: "google",
 	}
 	p.config = newConfig(p, scopes)
 	return p
 }
 
-// Provider is the implementation of `goth.Provider` for accessing Google+.
+// Provider is the implementation of `goth.Provider` for accessing Google.
 type Provider struct {
 	ClientKey    string
 	Secret       string
@@ -57,14 +51,15 @@ func (p *Provider) SetName(name string) {
 	p.providerName = name
 }
 
+// Client returns an HTTP client to be used in all fetch operations.
 func (p *Provider) Client() *http.Client {
 	return goth.HTTPClientWithFallBack(p.HTTPClient)
 }
 
-// Debug is a no-op for the gplus package.
+// Debug is a no-op for the google package.
 func (p *Provider) Debug(debug bool) {}
 
-// BeginAuth asks Google+ for an authentication end-point.
+// BeginAuth asks Google for an authentication endpoint.
 func (p *Provider) BeginAuth(state string) (goth.Session, error) {
 	var opts []oauth2.AuthCodeOption
 	if p.prompt != nil {
@@ -77,7 +72,17 @@ func (p *Provider) BeginAuth(state string) (goth.Session, error) {
 	return session, nil
 }
 
-// FetchUser will go to Google+ and access basic information about the user.
+type googleUser struct {
+	ID        string `json:"id"`
+	Email     string `json:"email"`
+	Name      string `json:"name"`
+	FirstName string `json:"given_name"`
+	LastName  string `json:"family_name"`
+	Link      string `json:"link"`
+	Picture   string `json:"picture"`
+}
+
+// FetchUser will go to Google and access basic information about the user.
 func (p *Provider) FetchUser(session goth.Session) (goth.User, error) {
 	sess := session.(*Session)
 	user := goth.User{
@@ -88,7 +93,7 @@ func (p *Provider) FetchUser(session goth.Session) (goth.User, error) {
 	}
 
 	if user.AccessToken == "" {
-		// data is not yet retrieved since accessToken is still empty
+		// Data is not yet retrieved, since accessToken is still empty.
 		return user, fmt.Errorf("%s cannot get user information without accessToken", p.providerName)
 	}
 
@@ -102,47 +107,30 @@ func (p *Provider) FetchUser(session goth.Session) (goth.User, error) {
 		return user, fmt.Errorf("%s responded with a %d trying to fetch user information", p.providerName, response.StatusCode)
 	}
 
-	bits, err := ioutil.ReadAll(response.Body)
+	responseBytes, err := ioutil.ReadAll(response.Body)
 	if err != nil {
 		return user, err
 	}
 
-	err = json.NewDecoder(bytes.NewReader(bits)).Decode(&user.RawData)
-	if err != nil {
+	var u googleUser
+	if err := json.Unmarshal(responseBytes, &u); err != nil {
 		return user, err
 	}
 
-	err = userFromReader(bytes.NewReader(bits), &user)
-	return user, err
-}
-
-func userFromReader(reader io.Reader, user *goth.User) error {
-	u := struct {
-		ID        string `json:"id"`
-		Email     string `json:"email"`
-		Name      string `json:"name"`
-		FirstName string `json:"given_name"`
-		LastName  string `json:"family_name"`
-		Link      string `json:"link"`
-		Picture   string `json:"picture"`
-	}{}
-
-	err := json.NewDecoder(reader).Decode(&u)
-	if err != nil {
-		return err
-	}
-
+	// Extract the user data we got from Google into our goth.User.
 	user.Name = u.Name
 	user.FirstName = u.FirstName
 	user.LastName = u.LastName
 	user.NickName = u.Name
 	user.Email = u.Email
-	//user.Description = u.Bio
 	user.AvatarURL = u.Picture
 	user.UserID = u.ID
-	//user.Location = u.Location.Name
+	// Google provides other useful fields such as 'hd'; get them from RawData
+	if err := json.Unmarshal(responseBytes, &user.RawData); err != nil {
+		return user, err
+	}
 
-	return err
+	return user, nil
 }
 
 func newConfig(provider *Provider, scopes []string) *oauth2.Config {
@@ -150,11 +138,8 @@ func newConfig(provider *Provider, scopes []string) *oauth2.Config {
 		ClientID:     provider.ClientKey,
 		ClientSecret: provider.Secret,
 		RedirectURL:  provider.CallbackURL,
-		Endpoint: oauth2.Endpoint{
-			AuthURL:  authURL,
-			TokenURL: tokenURL,
-		},
-		Scopes: []string{},
+		Endpoint:     Endpoint,
+		Scopes:       []string{},
 	}
 
 	if len(scopes) > 0 {
@@ -162,7 +147,7 @@ func newConfig(provider *Provider, scopes []string) *oauth2.Config {
 			c.Scopes = append(c.Scopes, scope)
 		}
 	} else {
-		c.Scopes = []string{"profile", "email", "openid"}
+		c.Scopes = []string{"email"}
 	}
 	return c
 }
@@ -183,7 +168,7 @@ func (p *Provider) RefreshToken(refreshToken string) (*oauth2.Token, error) {
 	return newToken, err
 }
 
-// SetPrompt sets the prompt values for the GPlus OAuth call. Use this to
+// SetPrompt sets the prompt values for the google OAuth call. Use this to
 // force users to choose and account every time by passing "select_account",
 // for example.
 // See https://developers.google.com/identity/protocols/OpenIDConnect#authenticationuriparameters

vendor/github.com/markbates/goth/providers/google/session.go

@@ -1,4 +1,4 @@
-package gplus
+package google
 
 import (
 	"encoding/json"
@@ -9,7 +9,7 @@ import (
 	"github.com/markbates/goth"
 )
 
-// Session stores data during the auth process with Google+.
+// Session stores data during the auth process with Google.
 type Session struct {
 	AuthURL      string
 	AccessToken  string
@@ -17,7 +17,7 @@ type Session struct {
 	ExpiresAt    time.Time
 }
 
-// GetAuthURL will return the URL set by calling the `BeginAuth` function on the Google+ provider.
+// GetAuthURL will return the URL set by calling the `BeginAuth` function on the Google provider.
 func (s Session) GetAuthURL() (string, error) {
 	if s.AuthURL == "" {
 		return "", errors.New(goth.NoAuthUrlErrorMessage)
@@ -25,7 +25,7 @@ func (s Session) GetAuthURL() (string, error) {
 	return s.AuthURL, nil
 }
 
-// Authorize the session with Google+ and return the access token to be stored for future use.
+// Authorize the session with Google and return the access token to be stored for future use.
 func (s *Session) Authorize(provider goth.Provider, params goth.Params) (string, error) {
 	p := provider.(*Provider)
 	token, err := p.config.Exchange(goth.ContextForClient(p.Client()), params.Get("code"))

vendor/golang.org/x/oauth2/google/appengine.go

@@ -0,0 +1,38 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package google
+
+import (
+	"context"
+	"time"
+
+	"golang.org/x/oauth2"
+)
+
+// Set at init time by appengine_gen1.go. If nil, we're not on App Engine standard first generation (<= Go 1.9) or App Engine flexible.
+var appengineTokenFunc func(c context.Context, scopes ...string) (token string, expiry time.Time, err error)
+
+// Set at init time by appengine_gen1.go. If nil, we're not on App Engine standard first generation (<= Go 1.9) or App Engine flexible.
+var appengineAppIDFunc func(c context.Context) string
+
+// AppEngineTokenSource returns a token source that fetches tokens from either
+// the current application's service account or from the metadata server,
+// depending on the App Engine environment. See below for environment-specific
+// details. If you are implementing a 3-legged OAuth 2.0 flow on App Engine that
+// involves user accounts, see oauth2.Config instead.
+//
+// First generation App Engine runtimes (<= Go 1.9):
+// AppEngineTokenSource returns a token source that fetches tokens issued to the
+// current App Engine application's service account. The provided context must have
+// come from appengine.NewContext.
+//
+// Second generation App Engine runtimes (>= Go 1.11) and App Engine flexible:
+// AppEngineTokenSource is DEPRECATED on second generation runtimes and on the
+// flexible environment. It delegates to ComputeTokenSource, and the provided
+// context and scopes are not used. Please use DefaultTokenSource (or ComputeTokenSource,
+// which DefaultTokenSource will use in this case) instead.
+func AppEngineTokenSource(ctx context.Context, scope ...string) oauth2.TokenSource {
+	return appEngineTokenSource(ctx, scope...)
+}

vendor/golang.org/x/oauth2/google/appengine_gen1.go

@@ -0,0 +1,77 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build appengine
+
+// This file applies to App Engine first generation runtimes (<= Go 1.9).
+
+package google
+
+import (
+	"context"
+	"sort"
+	"strings"
+	"sync"
+
+	"golang.org/x/oauth2"
+	"google.golang.org/appengine"
+)
+
+func init() {
+	appengineTokenFunc = appengine.AccessToken
+	appengineAppIDFunc = appengine.AppID
+}
+
+// See comment on AppEngineTokenSource in appengine.go.
+func appEngineTokenSource(ctx context.Context, scope ...string) oauth2.TokenSource {
+	scopes := append([]string{}, scope...)
+	sort.Strings(scopes)
+	return &gaeTokenSource{
+		ctx:    ctx,
+		scopes: scopes,
+		key:    strings.Join(scopes, " "),
+	}
+}
+
+// aeTokens helps the fetched tokens to be reused until their expiration.
+var (
+	aeTokensMu sync.Mutex
+	aeTokens   = make(map[string]*tokenLock) // key is space-separated scopes
+)
+
+type tokenLock struct {
+	mu sync.Mutex // guards t; held while fetching or updating t
+	t  *oauth2.Token
+}
+
+type gaeTokenSource struct {
+	ctx    context.Context
+	scopes []string
+	key    string // to aeTokens map; space-separated scopes
+}
+
+func (ts *gaeTokenSource) Token() (*oauth2.Token, error) {
+	aeTokensMu.Lock()
+	tok, ok := aeTokens[ts.key]
+	if !ok {
+		tok = &tokenLock{}
+		aeTokens[ts.key] = tok
+	}
+	aeTokensMu.Unlock()
+
+	tok.mu.Lock()
+	defer tok.mu.Unlock()
+	if tok.t.Valid() {
+		return tok.t, nil
+	}
+	access, exp, err := appengineTokenFunc(ts.ctx, ts.scopes...)
+	if err != nil {
+		return nil, err
+	}
+	tok.t = &oauth2.Token{
+		AccessToken: access,
+		Expiry:      exp,
+	}
+	return tok.t, nil
+}

vendor/golang.org/x/oauth2/google/appengine_gen2_flex.go

@@ -0,0 +1,27 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build !appengine
+
+// This file applies to App Engine second generation runtimes (>= Go 1.11) and App Engine flexible.
+
+package google
+
+import (
+	"context"
+	"log"
+	"sync"
+
+	"golang.org/x/oauth2"
+)
+
+var logOnce sync.Once // only spam about deprecation once
+
+// See comment on AppEngineTokenSource in appengine.go.
+func appEngineTokenSource(ctx context.Context, scope ...string) oauth2.TokenSource {
+	logOnce.Do(func() {
+		log.Print("google: AppEngineTokenSource is deprecated on App Engine standard second generation runtimes (>= Go 1.11) and App Engine flexible. Please use DefaultTokenSource or ComputeTokenSource.")
+	})
+	return ComputeTokenSource("")
+}

vendor/golang.org/x/oauth2/google/default.go

@@ -0,0 +1,154 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package google
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"os"
+	"path/filepath"
+	"runtime"
+
+	"cloud.google.com/go/compute/metadata"
+	"golang.org/x/oauth2"
+)
+
+// Credentials holds Google credentials, including "Application Default Credentials".
+// For more details, see:
+// https://developers.google.com/accounts/docs/application-default-credentials
+type Credentials struct {
+	ProjectID   string // may be empty
+	TokenSource oauth2.TokenSource
+
+	// JSON contains the raw bytes from a JSON credentials file.
+	// This field may be nil if authentication is provided by the
+	// environment and not with a credentials file, e.g. when code is
+	// running on Google Cloud Platform.
+	JSON []byte
+}
+
+// DefaultCredentials is the old name of Credentials.
+//
+// Deprecated: use Credentials instead.
+type DefaultCredentials = Credentials
+
+// DefaultClient returns an HTTP Client that uses the
+// DefaultTokenSource to obtain authentication credentials.
+func DefaultClient(ctx context.Context, scope ...string) (*http.Client, error) {
+	ts, err := DefaultTokenSource(ctx, scope...)
+	if err != nil {
+		return nil, err
+	}
+	return oauth2.NewClient(ctx, ts), nil
+}
+
+// DefaultTokenSource returns the token source for
+// "Application Default Credentials".
+// It is a shortcut for FindDefaultCredentials(ctx, scope).TokenSource.
+func DefaultTokenSource(ctx context.Context, scope ...string) (oauth2.TokenSource, error) {
+	creds, err := FindDefaultCredentials(ctx, scope...)
+	if err != nil {
+		return nil, err
+	}
+	return creds.TokenSource, nil
+}
+
+// FindDefaultCredentials searches for "Application Default Credentials".
+//
+// It looks for credentials in the following places,
+// preferring the first location found:
+//
+//   1. A JSON file whose path is specified by the
+//      GOOGLE_APPLICATION_CREDENTIALS environment variable.
+//   2. A JSON file in a location known to the gcloud command-line tool.
+//      On Windows, this is %APPDATA%/gcloud/application_default_credentials.json.
+//      On other systems, $HOME/.config/gcloud/application_default_credentials.json.
+//   3. On Google App Engine standard first generation runtimes (<= Go 1.9) it uses
+//      the appengine.AccessToken function.
+//   4. On Google Compute Engine, Google App Engine standard second generation runtimes
+//      (>= Go 1.11), and Google App Engine flexible environment, it fetches
+//      credentials from the metadata server.
+func FindDefaultCredentials(ctx context.Context, scopes ...string) (*Credentials, error) {
+	// First, try the environment variable.
+	const envVar = "GOOGLE_APPLICATION_CREDENTIALS"
+	if filename := os.Getenv(envVar); filename != "" {
+		creds, err := readCredentialsFile(ctx, filename, scopes)
+		if err != nil {
+			return nil, fmt.Errorf("google: error getting credentials using %v environment variable: %v", envVar, err)
+		}
+		return creds, nil
+	}
+
+	// Second, try a well-known file.
+	filename := wellKnownFile()
+	if creds, err := readCredentialsFile(ctx, filename, scopes); err == nil {
+		return creds, nil
+	} else if !os.IsNotExist(err) {
+		return nil, fmt.Errorf("google: error getting credentials using well-known file (%v): %v", filename, err)
+	}
+
+	// Third, if we're on a Google App Engine standard first generation runtime (<= Go 1.9)
+	// use those credentials. App Engine standard second generation runtimes (>= Go 1.11)
+	// and App Engine flexible use ComputeTokenSource and the metadata server.
+	if appengineTokenFunc != nil {
+		return &DefaultCredentials{
+			ProjectID:   appengineAppIDFunc(ctx),
+			TokenSource: AppEngineTokenSource(ctx, scopes...),
+		}, nil
+	}
+
+	// Fourth, if we're on Google Compute Engine, an App Engine standard second generation runtime,
+	// or App Engine flexible, use the metadata server.
+	if metadata.OnGCE() {
+		id, _ := metadata.ProjectID()
+		return &DefaultCredentials{
+			ProjectID:   id,
+			TokenSource: ComputeTokenSource("", scopes...),
+		}, nil
+	}
+
+	// None are found; return helpful error.
+	const url = "https://developers.google.com/accounts/docs/application-default-credentials"
+	return nil, fmt.Errorf("google: could not find default credentials. See %v for more information.", url)
+}
+
+// CredentialsFromJSON obtains Google credentials from a JSON value. The JSON can
+// represent either a Google Developers Console client_credentials.json file (as in
+// ConfigFromJSON) or a Google Developers service account key file (as in
+// JWTConfigFromJSON).
+func CredentialsFromJSON(ctx context.Context, jsonData []byte, scopes ...string) (*Credentials, error) {
+	var f credentialsFile
+	if err := json.Unmarshal(jsonData, &f); err != nil {
+		return nil, err
+	}
+	ts, err := f.tokenSource(ctx, append([]string(nil), scopes...))
+	if err != nil {
+		return nil, err
+	}
+	return &DefaultCredentials{
+		ProjectID:   f.ProjectID,
+		TokenSource: ts,
+		JSON:        jsonData,
+	}, nil
+}
+
+func wellKnownFile() string {
+	const f = "application_default_credentials.json"
+	if runtime.GOOS == "windows" {
+		return filepath.Join(os.Getenv("APPDATA"), "gcloud", f)
+	}
+	return filepath.Join(guessUnixHomeDir(), ".config", "gcloud", f)
+}
+
+func readCredentialsFile(ctx context.Context, filename string, scopes []string) (*DefaultCredentials, error) {
+	b, err := ioutil.ReadFile(filename)
+	if err != nil {
+		return nil, err
+	}
+	return CredentialsFromJSON(ctx, b, scopes...)
+}

vendor/golang.org/x/oauth2/google/doc.go

@@ -0,0 +1,40 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package google provides support for making OAuth2 authorized and authenticated
+// HTTP requests to Google APIs. It supports the Web server flow, client-side
+// credentials, service accounts, Google Compute Engine service accounts, and Google
+// App Engine service accounts.
+//
+// A brief overview of the package follows. For more information, please read
+// https://developers.google.com/accounts/docs/OAuth2
+// and
+// https://developers.google.com/accounts/docs/application-default-credentials.
+//
+// OAuth2 Configs
+//
+// Two functions in this package return golang.org/x/oauth2.Config values from Google credential
+// data. Google supports two JSON formats for OAuth2 credentials: one is handled by ConfigFromJSON,
+// the other by JWTConfigFromJSON. The returned Config can be used to obtain a TokenSource or
+// create an http.Client.
+//
+//
+// Credentials
+//
+// The Credentials type represents Google credentials, including Application Default
+// Credentials.
+//
+// Use FindDefaultCredentials to obtain Application Default Credentials.
+// FindDefaultCredentials looks in some well-known places for a credentials file, and
+// will call AppEngineTokenSource or ComputeTokenSource as needed.
+//
+// DefaultClient and DefaultTokenSource are convenience methods. They first call FindDefaultCredentials,
+// then use the credentials to construct an http.Client or an oauth2.TokenSource.
+//
+// Use CredentialsFromJSON to obtain credentials from either of the two JSON formats
+// described in OAuth2 Configs, above. The TokenSource in the returned value is the
+// same as the one obtained from the oauth2.Config returned from ConfigFromJSON or
+// JWTConfigFromJSON, but the Credentials may contain additional information
+// that is useful is some circumstances.
+package google // import "golang.org/x/oauth2/google"

vendor/golang.org/x/oauth2/google/google.go

@@ -0,0 +1,209 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package google
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"net/url"
+	"strings"
+	"time"
+
+	"cloud.google.com/go/compute/metadata"
+	"golang.org/x/oauth2"
+	"golang.org/x/oauth2/jwt"
+)
+
+// Endpoint is Google's OAuth 2.0 endpoint.
+var Endpoint = oauth2.Endpoint{
+	AuthURL:   "https://accounts.google.com/o/oauth2/auth",
+	TokenURL:  "https://oauth2.googleapis.com/token",
+	AuthStyle: oauth2.AuthStyleInParams,
+}
+
+// JWTTokenURL is Google's OAuth 2.0 token URL to use with the JWT flow.
+const JWTTokenURL = "https://oauth2.googleapis.com/token"
+
+// ConfigFromJSON uses a Google Developers Console client_credentials.json
+// file to construct a config.
+// client_credentials.json can be downloaded from
+// https://console.developers.google.com, under "Credentials". Download the Web
+// application credentials in the JSON format and provide the contents of the
+// file as jsonKey.
+func ConfigFromJSON(jsonKey []byte, scope ...string) (*oauth2.Config, error) {
+	type cred struct {
+		ClientID     string   `json:"client_id"`
+		ClientSecret string   `json:"client_secret"`
+		RedirectURIs []string `json:"redirect_uris"`
+		AuthURI      string   `json:"auth_uri"`
+		TokenURI     string   `json:"token_uri"`
+	}
+	var j struct {
+		Web       *cred `json:"web"`
+		Installed *cred `json:"installed"`
+	}
+	if err := json.Unmarshal(jsonKey, &j); err != nil {
+		return nil, err
+	}
+	var c *cred
+	switch {
+	case j.Web != nil:
+		c = j.Web
+	case j.Installed != nil:
+		c = j.Installed
+	default:
+		return nil, fmt.Errorf("oauth2/google: no credentials found")
+	}
+	if len(c.RedirectURIs) < 1 {
+		return nil, errors.New("oauth2/google: missing redirect URL in the client_credentials.json")
+	}
+	return &oauth2.Config{
+		ClientID:     c.ClientID,
+		ClientSecret: c.ClientSecret,
+		RedirectURL:  c.RedirectURIs[0],
+		Scopes:       scope,
+		Endpoint: oauth2.Endpoint{
+			AuthURL:  c.AuthURI,
+			TokenURL: c.TokenURI,
+		},
+	}, nil
+}
+
+// JWTConfigFromJSON uses a Google Developers service account JSON key file to read
+// the credentials that authorize and authenticate the requests.
+// Create a service account on "Credentials" for your project at
+// https://console.developers.google.com to download a JSON key file.
+func JWTConfigFromJSON(jsonKey []byte, scope ...string) (*jwt.Config, error) {
+	var f credentialsFile
+	if err := json.Unmarshal(jsonKey, &f); err != nil {
+		return nil, err
+	}
+	if f.Type != serviceAccountKey {
+		return nil, fmt.Errorf("google: read JWT from JSON credentials: 'type' field is %q (expected %q)", f.Type, serviceAccountKey)
+	}
+	scope = append([]string(nil), scope...) // copy
+	return f.jwtConfig(scope), nil
+}
+
+// JSON key file types.
+const (
+	serviceAccountKey  = "service_account"
+	userCredentialsKey = "authorized_user"
+)
+
+// credentialsFile is the unmarshalled representation of a credentials file.
+type credentialsFile struct {
+	Type string `json:"type"` // serviceAccountKey or userCredentialsKey
+
+	// Service Account fields
+	ClientEmail  string `json:"client_email"`
+	PrivateKeyID string `json:"private_key_id"`
+	PrivateKey   string `json:"private_key"`
+	TokenURL     string `json:"token_uri"`
+	ProjectID    string `json:"project_id"`
+
+	// User Credential fields
+	// (These typically come from gcloud auth.)
+	ClientSecret string `json:"client_secret"`
+	ClientID     string `json:"client_id"`
+	RefreshToken string `json:"refresh_token"`
+}
+
+func (f *credentialsFile) jwtConfig(scopes []string) *jwt.Config {
+	cfg := &jwt.Config{
+		Email:        f.ClientEmail,
+		PrivateKey:   []byte(f.PrivateKey),
+		PrivateKeyID: f.PrivateKeyID,
+		Scopes:       scopes,
+		TokenURL:     f.TokenURL,
+	}
+	if cfg.TokenURL == "" {
+		cfg.TokenURL = JWTTokenURL
+	}
+	return cfg
+}
+
+func (f *credentialsFile) tokenSource(ctx context.Context, scopes []string) (oauth2.TokenSource, error) {
+	switch f.Type {
+	case serviceAccountKey:
+		cfg := f.jwtConfig(scopes)
+		return cfg.TokenSource(ctx), nil
+	case userCredentialsKey:
+		cfg := &oauth2.Config{
+			ClientID:     f.ClientID,
+			ClientSecret: f.ClientSecret,
+			Scopes:       scopes,
+			Endpoint:     Endpoint,
+		}
+		tok := &oauth2.Token{RefreshToken: f.RefreshToken}
+		return cfg.TokenSource(ctx, tok), nil
+	case "":
+		return nil, errors.New("missing 'type' field in credentials")
+	default:
+		return nil, fmt.Errorf("unknown credential type: %q", f.Type)
+	}
+}
+
+// ComputeTokenSource returns a token source that fetches access tokens
+// from Google Compute Engine (GCE)'s metadata server. It's only valid to use
+// this token source if your program is running on a GCE instance.
+// If no account is specified, "default" is used.
+// If no scopes are specified, a set of default scopes are automatically granted.
+// Further information about retrieving access tokens from the GCE metadata
+// server can be found at https://cloud.google.com/compute/docs/authentication.
+func ComputeTokenSource(account string, scope ...string) oauth2.TokenSource {
+	return oauth2.ReuseTokenSource(nil, computeSource{account: account, scopes: scope})
+}
+
+type computeSource struct {
+	account string
+	scopes  []string
+}
+
+func (cs computeSource) Token() (*oauth2.Token, error) {
+	if !metadata.OnGCE() {
+		return nil, errors.New("oauth2/google: can't get a token from the metadata service; not running on GCE")
+	}
+	acct := cs.account
+	if acct == "" {
+		acct = "default"
+	}
+	tokenURI := "instance/service-accounts/" + acct + "/token"
+	if len(cs.scopes) > 0 {
+		v := url.Values{}
+		v.Set("scopes", strings.Join(cs.scopes, ","))
+		tokenURI = tokenURI + "?" + v.Encode()
+	}
+	tokenJSON, err := metadata.Get(tokenURI)
+	if err != nil {
+		return nil, err
+	}
+	var res struct {
+		AccessToken  string `json:"access_token"`
+		ExpiresInSec int    `json:"expires_in"`
+		TokenType    string `json:"token_type"`
+	}
+	err = json.NewDecoder(strings.NewReader(tokenJSON)).Decode(&res)
+	if err != nil {
+		return nil, fmt.Errorf("oauth2/google: invalid token JSON from metadata: %v", err)
+	}
+	if res.ExpiresInSec == 0 || res.AccessToken == "" {
+		return nil, fmt.Errorf("oauth2/google: incomplete token received from metadata")
+	}
+	tok := &oauth2.Token{
+		AccessToken: res.AccessToken,
+		TokenType:   res.TokenType,
+		Expiry:      time.Now().Add(time.Duration(res.ExpiresInSec) * time.Second),
+	}
+	// NOTE(cbro): add hidden metadata about where the token is from.
+	// This is needed for detection by client libraries to know that credentials come from the metadata server.
+	// This may be removed in a future version of this library.
+	return tok.WithExtra(map[string]interface{}{
+		"oauth2.google.tokenSource":    "compute-metadata",
+		"oauth2.google.serviceAccount": acct,
+	}), nil
+}

vendor/golang.org/x/oauth2/google/jwt.go

@@ -0,0 +1,74 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package google
+
+import (
+	"crypto/rsa"
+	"fmt"
+	"time"
+
+	"golang.org/x/oauth2"
+	"golang.org/x/oauth2/internal"
+	"golang.org/x/oauth2/jws"
+)
+
+// JWTAccessTokenSourceFromJSON uses a Google Developers service account JSON
+// key file to read the credentials that authorize and authenticate the
+// requests, and returns a TokenSource that does not use any OAuth2 flow but
+// instead creates a JWT and sends that as the access token.
+// The audience is typically a URL that specifies the scope of the credentials.
+//
+// Note that this is not a standard OAuth flow, but rather an
+// optimization supported by a few Google services.
+// Unless you know otherwise, you should use JWTConfigFromJSON instead.
+func JWTAccessTokenSourceFromJSON(jsonKey []byte, audience string) (oauth2.TokenSource, error) {
+	cfg, err := JWTConfigFromJSON(jsonKey)
+	if err != nil {
+		return nil, fmt.Errorf("google: could not parse JSON key: %v", err)
+	}
+	pk, err := internal.ParseKey(cfg.PrivateKey)
+	if err != nil {
+		return nil, fmt.Errorf("google: could not parse key: %v", err)
+	}
+	ts := &jwtAccessTokenSource{
+		email:    cfg.Email,
+		audience: audience,
+		pk:       pk,
+		pkID:     cfg.PrivateKeyID,
+	}
+	tok, err := ts.Token()
+	if err != nil {
+		return nil, err
+	}
+	return oauth2.ReuseTokenSource(tok, ts), nil
+}
+
+type jwtAccessTokenSource struct {
+	email, audience string
+	pk              *rsa.PrivateKey
+	pkID            string
+}
+
+func (ts *jwtAccessTokenSource) Token() (*oauth2.Token, error) {
+	iat := time.Now()
+	exp := iat.Add(time.Hour)
+	cs := &jws.ClaimSet{
+		Iss: ts.email,
+		Sub: ts.email,
+		Aud: ts.audience,
+		Iat: iat.Unix(),
+		Exp: exp.Unix(),
+	}
+	hdr := &jws.Header{
+		Algorithm: "RS256",
+		Typ:       "JWT",
+		KeyID:     string(ts.pkID),
+	}
+	msg, err := jws.Encode(hdr, cs, ts.pk)
+	if err != nil {
+		return nil, fmt.Errorf("google: could not encode JWT: %v", err)
+	}
+	return &oauth2.Token{AccessToken: msg, TokenType: "Bearer", Expiry: exp}, nil
+}

vendor/golang.org/x/oauth2/google/sdk.go

@@ -0,0 +1,201 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package google
+
+import (
+	"bufio"
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"os"