Chapter 6. Developing and deploying a Node.js application

In addition to using an example, you can create new Node.js applications from scratch and deploy them to OpenShift.

6.1. Developing a Node.js application

For a basic Node.js application, you must create a JavaScript file containing Node.js methods.

Prerequisites

  • npm installed.

Procedure

  1. Create a new directory myApp, and navigate to it. 

    $ mkdir myApp
$ cd MyApp

    This is the root directory for the application.

  2. Initialize your application with npm.

    The rest of this example assumes the entry point is app.js, which you are prompted to set when running npm init. 

    $ cd myApp
$ npm init

  3. Create the entry point in a new file called app.js.

    Example app.js

    const http = require('http');

const server = http.createServer((request, response) => {
  response.statusCode = 200;
  response.setHeader('Content-Type', 'application/json');

  const greeting = {content: 'Hello, World!'};

  response.write(JSON.stringify(greeting));
  response.end();
});

server.listen(8080, () => {
  console.log('Server running at http://localhost:8080');
});

  4. Start your application. 

    $ node app.js
Server running at http://localhost:8080

  5. Using curl or your browser, verify your application is running at http://localhost:8080. 

    $ curl http://localhost:8080
{"content":"Hello, World!"}

Additional information

6.2. Deploying a Node.js application to Openshift

To deploy your Node.js application to OpenShift, add nodeshift to the application, configure the package.json file and then deploy using nodeshift.

6.2.1. Preparing Node.js application for OpenShift deployment

To prepare a Node.js application for OpenShift deployment, you must perform the following steps:

  • Add nodeshift to the application.
  • Add openshift and start entries to the package.json file.

Prerequisites

  • npm installed.

Procedure

  1. Add nodeshift to your application. 

    $ npm install nodeshift --save-dev

  2. Add the openshift and start entries to the scripts section in package.json. 

    {
  "name": "myApp",
  "version": "1.0.0",
  "description": "",
  "main": "app.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1",
    "openshift": "nodeshift --expose --dockerImage=registry.access.redhat.com/rhscl/ubi8/nodejs-10",
    "start": "node app.js",
    ...
  }
  ...
}

    The openshift script uses nodeshift to deploy the application to OpenShift.

    Note

    Universal base images and RHEL images are available for Node.js. See the Node.js release notes for more information on image names.

  3. Optional: Add a files section in package.json. 

    {
  "name": "myApp",
  "version": "1.0.0",
  "description": "",
  "main": "app.js",
  "scripts": {
    ...
  },
  "files": [
    "package.json",
    "app.js"
  ]
  ...
}

    The files section tells nodeshift what files and directories to include when deploying to OpenShift. nodeshift uses the node-tar module to create a tar file based on the files and directories you list in the files section. This tar file is used when nodeshift deploys your application to OpenShift. If the files section is not specified, nodeshift will send the entire current directory, excluding:

    • node_modules/
    • .git/

    • tmp/

      It is recommended that you include a files section in package.json to avoid including unnecessary files when deploying to OpenShift.

6.2.2. Deploying a Node.js application to OpenShift

You can deploy a Node.js application to OpenShift using nodeshift.

Prerequisites

  • The oc CLI client installed.
  • npm installed.
  • Ensure all the ports used by your application are correctly exposed when configuring your routes.

Procedure

  1. Log in to your OpenShift instance with the oc client. 

    $ oc login ...

  2. Use nodeshift to deploy the application to OpenShift. 

    $ npm run openshift

6.3. Deploying a Node.js application to stand-alone Red Hat Enterprise Linux

You can deploy a Node.js application to stand-alone Red Hat Enterprise Linux using npm.

Prerequisites

  • A Node.js application.
  • npm 6.4.1 installed
  • RHEL 7 or RHEL 8 installed.
  • Node.js installed

Procedure

  1. If you have specified additional dependencies in the package.json file of your project, ensure that you install them before running your applications. 

    $ npm install

  2. Deploy the application from the application’s root directory. 

    $ node app.js
Server running at http://localhost:8080

Verification steps

  1. Use curl or your browser to verify your application is running at http://localhost:8080 

    $ curl http://localhost:8080