From 9ab8488a048791cb59f1d686eb0c6c01844548ec Mon Sep 17 00:00:00 2001
From: Stephen Sawchuk <sawchuk@gmail.com>
Date: Wed, 17 Sep 2014 11:26:28 -0400
Subject: [PATCH] fix(connection): set token expiration date for GCE

A response from the GCE metadata server responds with data in a
different format from that of the GAPIToken() request. Instead of
looking for a property that doesn't exist `token_expires`, we now
calculate the expiration timestamp from `expires_in`.

For more, see [Authenticating from Google Compute Engine][auth].

[auth]:https://developers.google.com/compute/docs/authentication#applications

Fixes #212
---
 lib/common/connection.js  |  2 +-
 test/common/connection.js | 35 +++++++++++++++++++++++++++++++++++
 2 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/lib/common/connection.js b/lib/common/connection.js
index 41470241cbae..7244a286b38f 100644
--- a/lib/common/connection.js
+++ b/lib/common/connection.js
@@ -165,7 +165,7 @@ Connection.prototype.fetchToken = function(callback) {
         callback(err);
         return;
       }
-      var exp = new Date(body.token_expires * 1000);
+      var exp = new Date(Date.now() + body.expires_in * 1000);
       callback(null, new Token(body.access_token, exp));
     });
     return;
diff --git a/test/common/connection.js b/test/common/connection.js
index 97740ff8bc8b..0c1a73c95ba5 100644
--- a/test/common/connection.js
+++ b/test/common/connection.js
@@ -98,6 +98,41 @@ describe('Connection', function() {
     var tokenNeverExpires = new connection.Token('token', new Date(3000, 0, 0));
     var tokenExpired = new connection.Token('token', new Date(2011, 0, 0));
 
+    describe('GCE', function() {
+      var gceConn;
+      var metadataResponse = {
+        body: {
+          access_token: 'y.8',
+          expires_in: 60
+        }
+      };
+
+      beforeEach(function() {
+        gceConn = new connection.Connection();
+      });
+
+      it('should fetch a token from the metadata server', function() {
+        gceConn.requester = function(opts) {
+          assert.equal(opts.uri.indexOf('http://metadata/'), 0);
+        };
+        gceConn.fetchToken();
+      });
+
+      it('should build token from metadata\'s response', function() {
+        gceConn.requester = function(opts, callback) {
+          callback(null, metadataResponse, metadataResponse.body);
+        };
+        gceConn.fetchToken(function(err, token) {
+          assert.ifError(err);
+          assert(token instanceof connection.Token);
+          assert.equal(token.accessToken, metadataResponse.body.access_token);
+          var addedMs = metadataResponse.body.expires_in * 1000;
+          var tokenDate = new Date(Date.now() + addedMs);
+          assert.equal(token.expiry.getTime(), tokenDate.getTime());
+        });
+      });
+    });
+
     it('should fetch a new token if token expires', function(done) {
       conn.token = tokenExpired;
       conn.fetchToken = function() {