Simple Express App with OpenTelemetry Integration

Overview

This repository contains a simple Express.js application that demonstrates the integration of OpenTelemetry for observability. The app provides basic CRUD operations for managing items and showcases how to instrument a Node.js application using the @middleware.io/node-apm package.

Features

• RESTful API for managing items (Create, Read, Update, Delete)
• OpenTelemetry integration for tracing and monitoring
• Custom span creation and attribute setting
• Error logging and handling
• Dockerized application for easy deployment
• Kubernetes deployment configuration

Prerequisites

• Node.js 18 or later
• Docker (for containerization)
• Kubernetes cluster (for deployment)

Installation

1. Clone the repository:

   git clone https://github.com/your-username/simple-express-app.git
   cd simple-express-app
   

2. Install dependencies:

   npm install
   

3. Set up environment variables: Copy the .env.example file to .env and fill in the required values:

   cp .env.example .env
   

Usage

Running Locally

To start the application in development mode:

npm start

To start the application with the Middleware.io agent:

npm run start-agent

The server will start on http://localhost:3000.

API Endpoints

• GET /items: Retrieve all items
• GET /items/:id: Retrieve a specific item
• POST /items: Create a new item
• PUT /items/:id: Update an existing item
• DELETE /items/:id: Delete an item

Docker

To build and run the Docker image:

docker build -t simple-express-app .
docker run -p 3000:3000 simple-express-app

Kubernetes

To deploy the application to Kubernetes:

kubectl apply -f deployment.yaml

OpenTelemetry Integration

This application uses the @middleware.io/node-apm package to integrate OpenTelemetry. Key features include:

• Automatic instrumentation of Express.js routes
• Custom span creation for specific operations
• Error logging and tracking
• Configuration of service name and API key through environment variables

Configuration

The application can be configured using the following environment variables:

• MW_SERVICE_NAME: Name of the service (default: "simple-express-app")
• MW_API_KEY: API key for Middleware.io
• MW_TARGET: Target URL for sending telemetry data
• MW_DEBUG: Enable debug mode (set to "true" to enable)
• PORT: Port on which the server will run (default: 3000)

Documentation

For detailed information on configuring and using the Middleware.io Node.js APM:

• Middleware.io Node.js APM Configuration

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

License

This project is licensed under the MIT License - see the LICENSE file for details.