bigtable: support local emulator

packages/bigtable/src/index.js

@@ -47,9 +47,30 @@ var Instance = require('./instance.js');
  * @resource [Google Cloud Bigtable Concepts Overview]{@link https://cloud.google.com/bigtable/docs/concepts}
  *
  * @param {object=} options - [Configuration object](#/docs).
+ * @param {string=} options.apiEndpoint - Override the default API endpoint used
+ *     to reach Bigtable. This is useful for connecting to your local Bigtable
+ *     emulator.
  *
  * @example
  * //-
+ * // <h3>The Bigtable Emulator</h3>
+ * //
+ * // Make sure you have the
+ * // [gcloud SDK installed](https://cloud.google.com/sdk/downloads), then run:
+ * //
+ * // <pre>
+ * //   $ gcloud beta emulators bigtable start
+ * // </pre>
+ * //
+ * // Before running your Node.js app, set the environment variables that this
+ * // library will look for to connect to the emulator:
+ * //
+ * // <pre>
+ * //   $ $(gcloud beta emulators bigtable env-init)
+ * // </pre>
+ * //-
+ *
+ * //-
  * // <h3>Creating a Compute Instance</h3>
  * //
  * // Before you create your table, you first need to create a Compute Instance
@@ -287,12 +308,22 @@ function Bigtable(options) {
     return new Bigtable(options);
   }
 
+  var baseUrl = 'bigtable.googleapis.com';
   var adminBaseUrl = 'bigtableadmin.googleapis.com';
 
+  var customEndpoint = options.apiEndpoint ||
+    process.env.BIGTABLE_EMULATOR_HOST;
+
+  if (customEndpoint) {
+    baseUrl = customEndpoint;
+    adminBaseUrl = baseUrl;
+  }
+
   var config = {
-    baseUrl: 'bigtable.googleapis.com',
+    baseUrl: baseUrl,
     service: 'bigtable',
     apiVersion: 'v2',
+    customEndpoint: !!customEndpoint,
     protoServices: {
       Bigtable: googleProtoFiles.bigtable.v2,
       BigtableTableAdmin: {

packages/bigtable/test/index.js

@@ -19,6 +19,7 @@
 var assert = require('assert');
 var extend = require('extend');
 var googleProtoFiles = require('google-proto-files');
+var is = require('is');
 var nodeutil = require('util');
 var proxyquire = require('proxyquire');
 var sinon = require('sinon').sandbox.create();
@@ -72,6 +73,7 @@ describe('Bigtable', function() {
   });
 
   beforeEach(function() {
+    delete process.env.BIGTABLE_EMULATOR_HOST;
     bigtable = new Bigtable({ projectId: PROJECT_ID });
   });
 
@@ -112,6 +114,7 @@ describe('Bigtable', function() {
       assert.strictEqual(calledWith.baseUrl, 'bigtable.googleapis.com');
       assert.strictEqual(calledWith.service, 'bigtable');
       assert.strictEqual(calledWith.apiVersion, 'v2');
+      assert.strictEqual(calledWith.customEndpoint, false);
 
       assert.deepEqual(calledWith.protoServices, {
         Bigtable: googleProtoFiles('bigtable/v2/bigtable.proto'),
@@ -145,6 +148,48 @@ describe('Bigtable', function() {
       assert.deepEqual(calledWith.packageJson, require('../package.json'));
     });
 
+    it('should work with the emulator', function() {
+      var endpoint = 'http://emulator:8288';
+      process.env.BIGTABLE_EMULATOR_HOST = endpoint;
+
+      var bigtable = new Bigtable({ projectId: PROJECT_ID });
+
+      var calledWith = bigtable.calledWith_[0];
+      assert.strictEqual(calledWith.baseUrl, endpoint);
+      assert.strictEqual(calledWith.customEndpoint, true);
+
+      Object.keys(calledWith.protoServices).forEach(function(service) {
+        service = calledWith.protoServices[service];
+
+        if (is.object(service)) {
+          assert.strictEqual(service.baseUrl, endpoint);
+        }
+      });
+
+      delete process.env.BIGTABLE_EMULATOR_HOST;
+    });
+
+    it('should work with a custom apiEndpoint', function() {
+      var options = {
+        projectId: PROJECT_ID,
+        apiEndpoint: 'http://local:3888'
+      };
+
+      var bigtable = new Bigtable(options);
+
+      var calledWith = bigtable.calledWith_[0];
+      assert.strictEqual(calledWith.baseUrl, options.apiEndpoint);
+      assert.strictEqual(calledWith.customEndpoint, true);
+
+      Object.keys(calledWith.protoServices).forEach(function(service) {
+        service = calledWith.protoServices[service];
+
+        if (is.object(service)) {
+          assert.strictEqual(service.baseUrl, options.apiEndpoint);
+        }
+      });
+    });
+
     it('should set the projectName', function() {
       assert.strictEqual(bigtable.projectName, 'projects/' + PROJECT_ID);
     });