core: make operations promise friendly (#1689)

Author: callmehiphop

packages/bigquery/src/job.js

@@ -312,6 +312,31 @@ Job.prototype.getQueryResultsStream = function(options) {
   return this.bigQuery.createQueryStream(options);
 };
 
+/**
+ * Convenience method that wraps the `complete` and `error` events in a
+ * Promise.
+ *
+ * @return {promise}
+ *
+ * @example
+ * job.promise().then(function(metadata) {
+ *   // The job is complete.
+ * }, function(err) {
+ *   // An error occurred during the job.
+ * });
+ */
+Job.prototype.promise = function() {
+  var self = this;
+
+  return new self.Promise(function(resolve, reject) {
+    self
+      .on('error', reject)
+      .on('complete', function(metadata) {
+        resolve([metadata]);
+      });
+  });
+};
+
 /**
  * Begin listening for events on the job. This method keeps track of how many
  * "complete" listeners are registered and removed, making sure polling is

packages/bigquery/test/job.js

@@ -50,7 +50,8 @@ var fakeUtil = Object.keys(util).reduce(function(fakeUtil, methodName) {
 
 describe('BigQuery/Job', function() {
   var BIGQUERY = {
-    projectId: 'my-project'
+    projectId: 'my-project',
+    Promise: Promise
   };
   var JOB_ID = 'job_XYrk_3z';
   var Job;
@@ -274,6 +275,45 @@ describe('BigQuery/Job', function() {
     });
   });
 
+  describe('promise', function() {
+    beforeEach(function() {
+      job.startPolling_ = util.noop;
+    });
+
+    it('should return an instance of the localized Promise', function() {
+      var FakePromise = job.Promise = function() {};
+      var promise = job.promise();
+
+      assert(promise instanceof FakePromise);
+    });
+
+    it('should reject the promise if an error occurs', function() {
+      var error = new Error('err');
+
+      setImmediate(function() {
+        job.emit('error', error);
+      });
+
+      return job.promise().then(function() {
+        throw new Error('Promise should have been rejected.');
+      }, function(err) {
+        assert.strictEqual(err, error);
+      });
+    });
+
+    it('should resolve the promise on complete', function() {
+      var metadata = {};
+
+      setImmediate(function() {
+        job.emit('complete', metadata);
+      });
+
+      return job.promise().then(function(data) {
+        assert.deepEqual(data, [metadata]);
+      });
+    });
+  });
+
   describe('listenForEvents_', function() {
     beforeEach(function() {
       job.startPolling_ = util.noop;

packages/common/src/grpc-operation.js

@@ -133,6 +133,23 @@ GrpcOperation.prototype.cancel = function(callback) {
   this.request(protoOpts, reqOpts, callback || util.noop);
 };
 
+/**
+ * Wraps the `complete` and `error` events in a Promise.
+ *
+ * @return {promise}
+ */
+GrpcOperation.prototype.promise = function() {
+  var self = this;
+
+  return new self.Promise(function(resolve, reject) {
+    self
+      .on('error', reject)
+      .on('complete', function(metadata) {
+        resolve([metadata]);
+      });
+  });
+};
+
 /**
  * Begin listening for events on the operation. This method keeps track of how
  * many "complete" listeners are registered and removed, making sure polling is

packages/common/src/service-object.js

@@ -71,6 +71,7 @@ function ServiceObject(config) {
   this.createMethod = config.createMethod;
   this.methods = config.methods || {};
   this.interceptors = [];
+  this.Promise = this.parent.Promise;
 
   if (config.methods) {
     var allMethodNames = Object.keys(ServiceObject.prototype);

packages/common/src/service.js

@@ -60,10 +60,7 @@ function Service(config, options) {
   this.packageJson = config.packageJson;
   this.projectId = options.projectId;
   this.projectIdRequired = config.projectIdRequired !== false;
-
-  if (options.promise) {
-    util.setPromiseOverride(options.promise);
-  }
+  this.Promise = options.promise || Promise;
 }
 
 /**

packages/common/src/util.js

@@ -51,8 +51,6 @@ var errorMessage = format([
   path: '/docs/guides/authentication'
 });
 
-var PromiseOverride;
-
 var missingProjectIdError = new Error(errorMessage);
 
 util.missingProjectIdError = missingProjectIdError;
@@ -656,7 +654,14 @@ function promisify(originalMethod) {
       return originalMethod.apply(context, args);
     }
 
-    var PromiseCtor = PromiseOverride || Promise;
+    var PromiseCtor = Promise;
+
+    // Because dedupe will likely create a single install of
+    // @google-cloud/common to be shared amongst all modules, we need to
+    // localize it at the Service level.
+    if (context && context.Promise) {
+      PromiseCtor = context.Promise;
+    }
 
     return new PromiseCtor(function(resolve, reject) {
       args.push(function() {
@@ -708,15 +713,3 @@ function promisifyAll(Class, options) {
 }
 
 util.promisifyAll = promisifyAll;
-
-/**
- * Allows user to override the Promise constructor without the need to touch
- * globals. Override should be ES6 Promise compliant.
- *
- * @param {promise} override
- */
-function setPromiseOverride(override) {
-  PromiseOverride = override;
-}
-
-module.exports.setPromiseOverride = setPromiseOverride;

packages/common/test/grpc-operation.js

@@ -47,7 +47,9 @@ var FakeGrpcServiceObject = createFake(GrpcServiceObject);
 var FakeGrpcService = createFake(GrpcService);
 
 describe('GrpcOperation', function() {
-  var FAKE_SERVICE = {};
+  var FAKE_SERVICE = {
+    Promise: Promise
+  };
   var OPERATION_ID = '/a/b/c/d';
 
   var GrpcOperation;
@@ -149,6 +151,45 @@ describe('GrpcOperation', function() {
     });
   });
 
+  describe('promise', function() {
+    beforeEach(function() {
+      grpcOperation.startPolling_ = util.noop;
+    });
+
+    it('should return an instance of the localized Promise', function() {
+      var FakePromise = grpcOperation.Promise = function() {};
+      var promise = grpcOperation.promise();
+
+      assert(promise instanceof FakePromise);
+    });
+
+    it('should reject the promise if an error occurs', function() {
+      var error = new Error('err');
+
+      setImmediate(function() {
+        grpcOperation.emit('error', error);
+      });
+
+      return grpcOperation.promise().then(function() {
+        throw new Error('Promise should have been rejected.');
+      }, function(err) {
+        assert.strictEqual(err, error);
+      });
+    });
+
+    it('should resolve the promise on complete', function() {
+      var metadata = {};
+
+      setImmediate(function() {
+        grpcOperation.emit('complete', metadata);
+      });
+
+      return grpcOperation.promise().then(function(data) {
+        assert.deepEqual(data, [metadata]);
+      });
+    });
+  });
+
   describe('listenForEvents_', function() {
     beforeEach(function() {
       grpcOperation.startPolling_ = util.noop;

packages/common/test/service-object.js

@@ -109,6 +109,19 @@ describe('ServiceObject', function() {
       assert.strictEqual(typeof serviceObject.create, 'function');
       assert.strictEqual(serviceObject.delete, undefined);
     });
+
+    it('should localize the Promise object', function() {
+      var FakePromise = function() {};
+      var config = extend({}, CONFIG, {
+        parent: {
+          Promise: FakePromise
+        }
+      });
+
+      var serviceObject = new ServiceObject(config);
+
+      assert.strictEqual(serviceObject.Promise, FakePromise);
+    });
   });
 
   describe('create', function() {

packages/common/test/service.js

@@ -150,15 +150,15 @@ describe('Service', function() {
       assert.strictEqual(service.projectIdRequired, true);
     });
 
-    it('should call setPromiseOverride when promise is set', function(done) {
+    it('should localize the Promise object', function() {
       var FakePromise = function() {};
+      var service = new Service({}, { promise: FakePromise });
 
-      util.setPromiseOverride = function(override) {
-        assert.strictEqual(override, FakePromise);
-        done();
-      };
+      assert.strictEqual(service.Promise, FakePromise);
+    });
 
-      new Service({}, { promise: FakePromise });
+    it('should localize the native Promise object by default', function() {
+      assert.strictEqual(service.Promise, global.Promise);
     });
   });
 

packages/common/test/util.js

@@ -1494,21 +1494,10 @@ describe('common/util', function() {
         assert.strictEqual(err, error);
       });
     });
-  });
-
-  describe('setPromiseOverride', function() {
-    var FakePromise = function() {};
-
-    before(function() {
-      util.setPromiseOverride(FakePromise);
-    });
-
-    after(function() {
-      util.setPromiseOverride(null);
-    });
 
-    it('should allow the Promise constructor to be specified', function() {
-      var promise = util.promisify(util.noop)();
+    it('should allow the Promise object to be overridden', function() {
+      var FakePromise = function() {};
+      var promise = func.call({ Promise: FakePromise });
 
       assert(promise instanceof FakePromise);
     });