Scale Service

Simple back-end service to demonstrate handling queues of background jobs.

Instead of having to wait, an id is returned that can be used to query that status of the job.

Get Started

git clone git@github.com:dayvidwhy/scale-service.git
cd scale-service
npm i
npm run start:dev

Development

# Start the dev container
docker compose up --build

# Open a container shell
docker exec -it scale-service bash

Production scaling testing

A docker-compose.yml file is provided to scale the local environment for testing.

Working with docker swarm we can scale up the number of containers and load balance between them.

We can then leverage postman performance testing to do a small scale load test of our service.

# Initiate the swarm
docker swarm init

# build and deploy the app
docker build -t dayvidwhy/scale-service:tag .

# docker stack deploy does not read in the .env file during startup 
# so we instead use another script that executes the necessary command:
# docker stack deploy -c docker-compose-scale.yml scale-service
node deploy.mjs scale-service

# clean up and leave when finished
docker stack rm scale-service
docker swarm leave --force

Adding more modules

Run the following commands replacing [moduleName] with the intended name.

npx @nestjs/cli generate module [moduleName]
npx @nestjs/cli generate service [moduleName]
npx @nestjs/cli generate controller [moduleName]

The new module will be available in ./src/[moduleName].

Test

npm run test
npm run test:e2e
npm run test:cov