Quickstart for Node.js in the App Engine Flexible Environment

This quickstart shows you how to create a small App Engine application that displays a short message.

Before you begin

Before running and deploying this sample, take the following steps:

1. Use the GCP Console to create a new GCP project, create an App Engine application, and enable billing:
   Go to App Engine When prompted, select the region where you want your App Engine application located and then enable billing.
   
2. Install the following prerequisites locally:
   1. Download and install git.
   2. Prepare your environment for Node.js development.
   3. Download and install the Google Cloud SDK and then initialize the gcloud tool:
      Download the SDK
3. Alternatively: You can use Google Cloud Shell, which comes with git and Cloud SDK already installed, and many other features, such as language support and code editors. After Google Cloud Shell is launched, you can proceed with the rest of this tutorial and execute your commands within Cloud Shell.
   

This quickstart demonstrates a simple Node.js application written with the Express.js framework.

Important: For the best experience on Windows, upgrade to the latest npm by running npm install -g npm. The latest npm installs dependencies in a flat directory structure, so installations are unlikely to conflict with the Windows maximum pathname length of 255 characters. If you prefer to keep using an older version of npm, you can reduce the length of pathnames by moving your project to the root of your drive, for example c:\.

Download the Hello World app

We've created a simple Hello World app for Node.js so you can quickly get a feel for deploying an app to the App Engine flexible environment. Follow these steps from a command line to download Hello World to your local machine.
Download the sample app and navigate into the app directory:

1. Clone the Hello World sample app repository to your local machine:
   

   git clone https://github.com/GoogleCloudPlatform/nodejs-docs-samples
   

   Alternatively, you can download the sample as a zip file and extract it.
   
2. Change to the directory that contains the sample code:
   

   cd nodejs-docs-samples/appengine/hello-world/flexible

Run Hello World on your local machine

1. Install dependencies for this project by entering the following command:
   

   npm install

   or if you are using Yarn:
   

   yarn install

2. Run the start script.
   

   npm start

   or if you are using Yarn:
   

   yarn start

3. View your app in your web browser:
   
   • If you are using Cloud Shell, in the toolbar, click Web Preview and select Preview on port 8080 instead.
     
   • If you are not using Cloud Shell, enter the following address:
     

     http://localhost:8080
     

You can see the Hello World message from the sample app displayed in the page.
In your terminal window, press Ctrl+C to exit the web server.

Deploy and run Hello World on App Engine

To deploy your app to the App Engine flexible environment:

1. Deploy the Hello World app by running the following command from the hello-world/flexible directory:
   

   gcloud app deploy

   Learn about the optional flags.
   Note: During deployment npm install is used by default to install dependencies unless a yarn.lock file exists and is not listed in the app.yaml file's skip_files section, in which case yarn install --production is used instead. To cause the build to fall back to npm install delete the yarn.lock file or add yarn.lock to the skip_files section of your app.yaml file.
2. Launch your browser and view the app at http://YOUR_PROJECT_ID.appspot.com, by running the following command:
   

   gcloud app browse

This time, the page that displays the Hello World message is delivered by a web server running on an App Engine instance. Congratulations! You've deployed your first Node.js app to App Engine flexible environment!
See the following sections for information about cleaning up as well as links to the possible next steps that you can take.

Clean up

To avoid incurring charges, you can delete your GCP project to stop billing for all the resources used within that project.

Warning: Deleting a project has the following consequences:
• If you used an existing project, you'll also delete any other work you've done in the project.
• You can't reuse the project ID of a deleted project. If you created a custom project ID that you plan to use in the future, delete the resources inside the project instead. This step ensures that URLs that use the project ID, such as an appspot.com URL, remain available.
1. In the GCP Console, go to the Projects page. Go to the Projects page
   
2. In the project list, select the project you want to delete and click Delete project.
3. In the dialog, type the project ID, and then click Shut down to delete the project.

What's next

Learn the whole platform

Now that you know what it's like to develop and deploy App Engine apps, you can stretch out and see the rest of Google Cloud Platform. You already have the Google Cloud SDK installed and that gives you the tools to interact with products like Google Cloud SQL, Google Cloud Storage, Google Cloud Datastore, and more. For a guided walkthrough that teaches you how to create an application that uses the entire platform, not just App Engine, check out our quickstart on creating the Bookshelf app.

Learn about the App Engine flexible environment

Here are some topics to help continue your learning about App Engine.

• An Overview of App Engine
• How Requests are Routed
• How Requests are Handled
• How Instances are Managed

Hello World code review

Hello World is the simplest possible App Engine app, as it contains only one service, has only one version, and all of the code is located within the app's root directory. This section describes each of the app files in detail.

app.js

The app.js file contains the JavaScript code to start a server and respond to requests.
The following code responds to requests from web clients by displaying the 'Hello World' message, via a server that runs on port 8080.

appengine/hello-world/flexible/app.js

View on GitHub

const express = require('express');
const app = express();

app.get('/', (req, res) => {
  res.status(200).send('Hello, world!').end();
});
// Start the server
const PORT = process.env.PORT || 8080;
app.listen(PORT, () => {
  console.log(`App listening on port ${PORT}`);
  console.log('Press Ctrl+C to quit.');
});

app.yaml

The app.yaml file describes an application's deployment configuration:

appengine/hello-world/flexible/app.yaml

View on GitHub

runtime: nodejsenv: flex
# This sample incurs costs to run on the App Engine flexible environment. 
# The settings below are to reduce costs during testing and are not appropriate
# for production use. For more information, see:
# https://cloud.google.com/appengine/docs/flexible/nodejs/configuring-your-app-with-app-yaml
manual_scaling:  instances: 1resources:  cpu: 1
  memory_gb: 0.5
  disk_size_gb: 10

Here, app.yaml specifies the runtime used by the app, and sets env: flex, specifying that the app uses the flexible environment.

• For more information on how the Node.js runtime works, see The Node.js Runtime.
  
• For more details about how to design your app to take advantage of versions and services, see An Overview of App Engine.
  
• For more details about the configuration settings for App Engine, see Configuring Your App with app.yaml.
  

package.json

package.json is used to specify application dependencies, node version, and application startup.

appengine/hello-world/flexible/package.json

View on GitHub

{
  "name": "appengine-hello-world",
  "description": "Simple Hello World Node.js sample for Google App Engine Flexible Environment.",
  "version": "0.0.1",
  "private": true,
  "license": "Apache-2.0",
  "author": "Google Inc.",
  "repository": {
    "type": "git",
    "url": "https://github.com/GoogleCloudPlatform/nodejs-docs-samples.git"
  },
  "engines": {
    "node": ">=4.3.2"
  },
  "scripts": {
    "deploy": "gcloud app deploy",
    "start": "node app.js",
    "lint": "repo-tools lint",
    "pretest": "npm run lint",
    "system-test": "repo-tools test app",
    "test": "npm run system-test",
    "e2e-test": "repo-tools test deploy"
  },
  "dependencies": {
    "express": "4.16.2"
  },
  "devDependencies": {
    "@google-cloud/nodejs-repo-tools": "2.2.1"
  },
  "cloud-repo-tools": {
    "test": {
      "app": {
        "msg": "Hello, world!"
      }
    },
    "requiresKeyFile": true,
    "requiresProjectId": true
  }
}

This package.json specifies that the application uses Node.js v4.3.2 or later, depends on express, and that node app.js is used to start the application. For more details about how your application is installed and run, see the Node.js runtime documentation.