storage: add storage class enums

lib/storage/index.js

@@ -184,11 +184,18 @@ Storage.prototype.bucket = function(name) {
  * Create a bucket.
  *
  * @resource [Buckets: insert API Documentation]{@link https://cloud.google.com/storage/docs/json_api/v1/buckets/insert}
+ * @resource [Durable Reduced Availability]{@link https://cloud.google.com/storage/docs/durable-reduced-availability}
+ * @resource [Nearline]{@link https://cloud.google.com/storage/docs/nearline}
+ * @resource [Storage Classes]{@link https://cloud.google.com/storage/docs/storage-classes}
  *
  * @throws {Error} If a name is not provided.
  *
  * @param {string} name - Name of the bucket to create.
  * @param {object=} metadata - Metadata to set for the bucket.
+ * @param {boolean=} metadata.dra - Specify the storage class as
+ *     [Durable Reduced Availability](https://goo.gl/26lthK).
+ * @param {boolean=} metadata.nearline - Specify the storage class as
+ *     [Nearline](https://goo.gl/sN5wNh).
  * @param {function} callback - The callback function.
  * @param {?error} callback.err - An error returned while making this request
  * @param {module:storage/bucket} callback.bucket - The newly created Bucket.
@@ -209,7 +216,7 @@ Storage.prototype.bucket = function(name) {
  * //-
  * var metadata = {
  *   location: 'US-CENTRAL1',
- *   storageClass: 'DURABLE_REDUCED_AVAILABILITY'
+ *   dra: true
  * };
  *
  * gcs.createBucket('new-bucket', metadata, callback);
@@ -240,6 +247,17 @@ Storage.prototype.createBucket = function(name, metadata, callback) {
   var body = extend(metadata, {
     name: name
   });
+  var storageClasses = {
+    dra: 'DURABLE_REDUCED_AVAILABILITY',
+    nearline: 'NEARLINE'
+  };
+
+  Object.keys(storageClasses).forEach(function(storageClass) {
+    if (body[storageClass]) {
+      body.storageClass = storageClasses[storageClass];
+      delete body[storageClass];
+    }
+  });
 
   this.makeReq_('POST', '', query, body, function(err, resp) {
     if (err) {

test/storage/index.js

@@ -173,6 +173,23 @@ describe('Storage', function() {
         done();
       });
     });
+
+    it('should expand the Nearline option', function(done) {
+      storage.makeReq_ = function(method, path, query, body) {
+        assert.strictEqual(body.storageClass, 'NEARLINE');
+        done();
+      };
+      storage.createBucket(BUCKET_NAME, { nearline: true }, function() {});
+    });
+
+    it('should expand the Durable Reduced Availability option', function(done) {
+      storage.makeReq_ = function(method, path, query, body) {
+        assert.strictEqual(body.storageClass, 'DURABLE_REDUCED_AVAILABILITY');
+        done();
+      };
+      storage.createBucket(BUCKET_NAME, { dra: true }, function() {});
+    });
+
   });
 
   describe('getBuckets', function() {