Merge pull request #900 from sparkprime/oauth2

Port to oauth2, fix #606

builtin/providers/google/config.go

@@ -7,12 +7,13 @@ import (
 	"net/http"
 	"os"
 
-	"code.google.com/p/goauth2/oauth"
-	"code.google.com/p/goauth2/oauth/jwt"
 	"code.google.com/p/google-api-go-client/compute/v1"
+
+	"golang.org/x/oauth2"
+	"golang.org/x/oauth2/google"
+	"golang.org/x/oauth2/jwt"
 )
 
-const clientScopes string = "https://www.googleapis.com/auth/compute"
 
 // Config is the configuration structure used to instantiate the Google
 // provider.
@@ -38,6 +39,9 @@ func (c *Config) loadAndValidate() error {
 		c.Region = os.Getenv("GOOGLE_REGION")
 	}
 
+	var client *http.Client
+
+	if c.AccountFile != "" {
 		if err := loadJSON(&account, c.AccountFile); err != nil {
 			return fmt.Errorf(
 				"Error loading account file '%s': %s",
@@ -45,31 +49,42 @@ func (c *Config) loadAndValidate() error {
 				err)
 		}
 
+		clientScopes := []string{"https://www.googleapis.com/auth/compute"}
+
 		// Get the token for use in our requests
 		log.Printf("[INFO] Requesting Google token...")
 		log.Printf("[INFO]   -- Email: %s", account.ClientEmail)
 		log.Printf("[INFO]   -- Scopes: %s", clientScopes)
 		log.Printf("[INFO]   -- Private Key Length: %d", len(account.PrivateKey))
-	jwtTok := jwt.NewToken(
-		account.ClientEmail,
-		clientScopes,
-		[]byte(account.PrivateKey))
-	token, err := jwtTok.Assert(new(http.Client))
-	if err != nil {
-		return fmt.Errorf("Error retrieving auth token: %s", err)
+
+		conf := jwt.Config{
+			Email:      account.ClientEmail,
+			PrivateKey: []byte(account.PrivateKey),
+			Scopes:     clientScopes,
+			TokenURL:   "https://accounts.google.com/o/oauth2/token",
 		}
 
-	// Instantiate the transport to communicate to Google
-	transport := &oauth.Transport{
-		Config: &oauth.Config{
-			ClientId: account.ClientId,
-			Scope:    clientScopes,
+		// Initiate an http.Client. The following GET request will be
+		// authorized and authenticated on the behalf of
+		// your service account.
+		client = conf.Client(oauth2.NoContext)
+
+	} else {
+		log.Printf("[INFO] Requesting Google token via GCE Service Role...")
+		client = &http.Client{
+			Transport: &oauth2.Transport{
+				// Fetch from Google Compute Engine's metadata server to retrieve
+				// an access token for the provided account.
+				// If no account is specified, "default" is used.
+				Source: google.ComputeTokenSource(""),
 			},
-		Token: token,
+		}
+
 	}
 
 	log.Printf("[INFO] Instantiating GCE client...")
-	c.clientCompute, err = compute.New(transport.Client())
+	var err error
+	c.clientCompute, err = compute.New(client)
 	if err != nil {
 		return err
 	}

builtin/providers/google/provider.go

@@ -11,7 +11,7 @@ func Provider() terraform.ResourceProvider {
 		Schema: map[string]*schema.Schema{
 			"account_file": &schema.Schema{
 				Type:        schema.TypeString,
-				Required:    true,
+				Optional:    true,
 				DefaultFunc: schema.EnvDefaultFunc("GOOGLE_ACCOUNT_FILE", nil),
 			},
 

website/source/docs/providers/google/index.html.markdown

@@ -34,9 +34,11 @@ resource "google_compute_instance" "default" {
 
 The following keys can be used to configure the provider.
 
-* `account_file` - (Required) Path to the JSON file used to describe
-  your account credentials, downloaded from Google Cloud Console. More
-  details on retrieving this file are below.
+* `account_file` - (Required) Path to the JSON file used to describe your
+  account credentials, downloaded from Google Cloud Console. More details on
+  retrieving this file are below.  The _account file_ can be "" if you
+  are running terraform from a GCE instance with a properly-configured [Compute
+  Engine Service Account](https://cloud.google.com/compute/docs/authentication).
 
 * `project` - (Required) The name of the project to apply any resources to.