Run and Test NodeJS App on Local Machine

Learn how to run and test the Solar System Node.js application locally before integrating it into a GitLab CI/CD pipeline. The source code is hosted on GitLab.

The image shows a GitLab repository page for a project named "Solar-System," displaying the project files and their last commit details. The interface includes options for managing, planning, and deploying the project.

Prerequisites

Node.js and npm
A running MongoDB instance or Atlas cluster
Git installed on your machine

To verify Node.js and npm:

node --version   # e.g., v18.x.x
npm --version    # e.g., 9.x.x

Clone the Repository

git clone https://gitlab.com/sidd-harth/solar-system.git
cd solar-system

Project Structure and Key Files

This repository includes:

package.json: Defines metadata, scripts, dependencies, and coverage thresholds
app.js: Backend Express.js server
client.js: Frontend script to fetch planet data
Dockerfile: Build instructions for a Docker image
deployment.yaml & service.yaml: Kubernetes manifests

package.json

{
  "name": "Solar System",
  "version": "6.7.6",
  "author": "Siddharth Barahalikar",
  "license": "MIT",
  "scripts": {
    "start": "node app.js",
    "test": "mocha app-test.js --timeout 10000 --reporter mocha-junit-reporter --exit",
    "coverage": "nyc --reporter cobertura --reporter lcov --reporter text --reporter json-summary mocha app-test.js"
  },
  "nyc": {
    "check-coverage": true,
    "lines": 90
  },
  ...
}

Script	Description	Command
start	Launch the Express server	`npm start`
test	Run tests with Mocha and JUnit reporter	`npm test`
coverage	Generate coverage reports (cobertura, lcov)	`npm run coverage`

Application Backend (app.js)

const path = require('path');
const express = require('express');
const bodyParser = require('body-parser');
const cors = require('cors');
const mongoose = require('mongoose');

const app = express();
app.use(bodyParser.json());
app.use(express.static(path.join(__dirname, '/')));
app.use(cors());

mongoose.connect(process.env.MONGO_URI, {
  user: process.env.MONGO_USERNAME,
  pass: process.env.MONGO_PASSWORD,
  useNewUrlParser: true,
  useUnifiedTopology: true
}, (err) => {
  if (err) {
    console.error("Connection error:", err);
  } else {
    console.log("Connected to MongoDB");
  }
});

app.listen(3000, () => {
  console.log("Server running on port 3000");
});

Ensure you add your REST API route handlers in app.js (for example, a GET /os endpoint) before testing.

Frontend Controller (client.js)

console.log('Client script loaded');

window.onload = () => {
  console.log("Requesting all planets");
  fetch("/os", { method: "GET" })
    .then(res => res.ok ? res.json() : Promise.reject("Fetch error"))
    .then(data => console.log(data))
    .catch(error => console.error(error));
};

Dockerfile

FROM node:18-alpine3.17
WORKDIR /usr/app
COPY package*.json ./
RUN npm install
COPY . .
ENV MONGO_URI=uriPlaceholder
ENV MONGO_USERNAME=usernamePlaceholder
ENV MONGO_PASSWORD=passwordPlaceholder
EXPOSE 3000
CMD ["npm", "start"]

Kubernetes Manifests

# deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: solar-system
  labels:
    app: solar-system
spec:
  replicas: 2
  selector:
    matchLabels:
      app: solar-system
  template:
    metadata:
      labels:
        app: solar-system
    spec:
      containers:
        - name: solar-system
          image: your-repo/solar-system:latest
          ports:
            - containerPort: 3000
---
# service.yaml
apiVersion: v1
kind: Service
metadata:
  name: solar-system
  labels:
    app: solar-system
spec:
  type: NodePort
  selector:
    app: solar-system
  ports:
    - port: 3000
      targetPort: 3000
      protocol: TCP

Resource Type	Purpose	Example
Deployment	Manages pods and rolling updates	Defined in `deployment.yaml`
Service	Exposes pods on the network	Defined in `service.yaml`

Install Dependencies

npm install

You may see notices:

44 packages are looking for funding
Run `npm fund` for details

1 high severity vulnerability
To address all issues, run:
  npm audit fix

Running the Server Locally

After dependencies are installed:

npm start

Open http://localhost:3000 in your browser:

The image shows a digital illustration of the solar system with planets orbiting the sun, accompanied by a user interface for searching planets. The background is a starry space theme with text describing the solar system.

You can search by ID (e.g., 3 for Earth, 6 for Saturn). Data is fetched from your MongoDB.

The image shows a webpage about the solar system, specifically focusing on Saturn, with a stylized illustration of the planet and its rings on a starry background. There is a description of Saturn and a search feature for exploring planets.

Testing the Application

Run the test suite:

npm test

If environment variables are missing, you will see:

MongooseError: The `uri` parameter to `openUri()` must be a string, got `undefined`.

Tests will fail without MONGO_URI, MONGO_USERNAME, and MONGO_PASSWORD. Set these before running npm test.

Temporary Local Credentials

For a quick local demo, hard-code your MongoDB URI in app.js:

mongoose.connect('mongodb+srv://supercluster.d83jj.mongodb.net/superData', {
  user: 'superuser',
  pass: 'SuperPassword',
  useNewUrlParser: true,
  useUnifiedTopology: true
}, (err) => {
  if (err) console.error("Connection error:", err);
});

Re-run tests:

npm test
echo $?   # 0 means success

A test_results.xml file is generated for CI/CD:

<?xml version="1.0" encoding="UTF-8"?>
<testsuites name="Mocha Tests" time="3.953" tests="11" failures="0">
  <testsuite name="Planets API Suite" tests="8" time="3.953">
    <testcase name="Fetching Planet Details - Mercury" time="2.350" />
    <testcase name="Fetching Planet Details - Venus" time="0.224" />
    <!-- more testcases -->
  </testsuite>
</testsuites>

Coverage Report

Generate coverage:

npm run coverage

11 passing (4s)
ERROR: Coverage for lines (88.88%) does not meet global threshold (90%)

A non-zero exit code will signal coverage failures in CI pipelines.

Introduction

Architecture & Core Concepts

Continuous Integration with GitLab

Continuous Deployment with GitLab

Optimization, Security and Monitoring

Self-Managed Runners

Auto DevOps

Run and Test NodeJS App on Local Machine

Prerequisites

Clone the Repository

Project Structure and Key Files

package.json

Application Backend (app.js)

Frontend Controller (client.js)

Dockerfile

Kubernetes Manifests

Install Dependencies

Running the Server Locally

Testing the Application

Temporary Local Credentials

Coverage Report

Links and References

Watch Video

​Prerequisites

​Clone the Repository

​Project Structure and Key Files

​package.json

​Application Backend (app.js)

​Frontend Controller (client.js)

​Dockerfile

​Kubernetes Manifests

​Install Dependencies

​Running the Server Locally

​Testing the Application

​Temporary Local Credentials

​Coverage Report

​Links and References

Watch Video

Prerequisites

Clone the Repository

Project Structure and Key Files

package.json

Application Backend (app.js)

Frontend Controller (client.js)

Dockerfile

Kubernetes Manifests

Install Dependencies

Running the Server Locally

Testing the Application

Temporary Local Credentials

Coverage Report

Links and References