SNOMED CT Concept Diagram API

This API provides a way to generate a concept diagram for a given SNOMED CT concept. The diagram is generated as an SVG image and returned as a PNG file.

Usage

To start this Node.js microservice run node app/server.js.

To use the API first load the concept JSON object from Snowstorm using GET /browser/{branch}/concepts/{conceptId}

Then make a POST request to this app's endpoint, sending the concept JSON in the body of the request.

http://localhost:3000/diagram

The response will be the concept diagram as a PNG image.

An example diagram can be generated using http://localhost:3000/test

Maven Build and Debian Package Deployment

This project includes a Maven build configuration that creates a Debian package for easy deployment on Ubuntu systems with supervisorctl process management.

Prerequisites

• Java 11 or higher
• Maven 3.6 or higher
• Node.js 18+ (will be installed automatically by the build)

Building the Debian Package

# Clean and build the Debian package
mvn clean package

# The Debian package will be created at:
# target/snomed-diagram-api-1.1.0-all.deb

Installing the Debian Package

Prerequisites

Before installing the package, ensure you have the required dependencies:

# Add NodeJS debian package source
curl -fsSL https://deb.nodesource.com/setup_20.x | sudo -E bash -

# Update package list
sudo apt-get update

# Install NodeJS 20.x
sudo apt-get install nodejs

Installation

# Install the package (requires sudo)
sudo dpkg -i snomed-diagram-api-*.deb

# If there are dependency issues, fix them with:
sudo apt-get install -f

# Setup puppeteer with fixed version of chrome
sudo -u snomed-diagram PUPPETEER_CACHE_DIR=/opt/snomed-diagram-api/.cache/puppeteer npx puppeteer browsers install [email protected]

# Add chrome dependencies
sudo apt-get install -y \
  libgbm1 libdrm2 libxshmfence1 libx11-xcb1 libxcomposite1 libxdamage1 libxrandr2 \
  libatk-bridge2.0-0 libatk1.0-0 libgtk-3-0 libnss3 libxss1 libasound2 \
  libcups2 libxkbcommon0 libxkbcommon-x11-0 libxfixes3 libglib2.0-0 \
  fonts-liberation ca-certificates xdg-utils

Service Management

The package installs the application as a system service managed by supervisorctl:

# Check service status
sudo supervisorctl status snomed-diagram-api:

# Start the service
sudo supervisorctl start snomed-diagram-api:

# Stop the service
sudo supervisorctl stop snomed-diagram-api:

# Restart the service
sudo supervisorctl restart snomed-diagram-api:

# View logs
sudo tail -f /var/log/snomed-diagram-api/out.log
sudo tail -f /var/log/snomed-diagram-api/err.log

Package Contents

The Debian package installs:

• Application files: /opt/snomed-diagram-api/
• Supervisor config: /etc/supervisor/conf.d/snomed-diagram-api.conf
• Startup script: /opt/snomed-diagram-api/start.sh
• Logs: /var/log/snomed-diagram-api/

Dependencies

The package automatically installs these system dependencies:

• Node.js 18+
• npm 9+
• supervisor
• chromium-browser (for Puppeteer)

Development

For development, you can still use the standard Node.js workflow:

# Install dependencies
npm install

# Start in development mode
npm run dev

# Start in production mode
npm start

Note

This is a quick and dirty app intended for internal backend use only.