kevinchabreck/paintchat repository overview

⁠PaintChat

A distributed chatroom with support for real-time collaborative drawing. Think MS Paint meets Google Docs!

Live demo⁠

Read the whitepaper⁠

⁠Features

• run as a single instance or as multiple clustered nodes
• consistent, persistant state
• dynamically add/remove nodes at any time
• out of the box service discovery and load balancing with zero configuration

⁠Getting started

Download and install Docker for Mac or Windows⁠.

⁠Run a local PaintChat instance

Run in this directory:

$ docker-compose up

⁠Connect to the PaintChat cluster

Point your browser to http://paintchat.localhost:8080/⁠

tip: open in multiple tabs for realtime collaborative drawing

⁠Advanced usage

Running docker-compose up will create 3 containers on your machine:

• paintchat: a paintchat server node
• traefik: a traefik⁠ instance for dynamic load balancing
• cassandra: a cassandra⁠ db instance for data persistence

You can run multiple instances of the paintchat service together as a cluster. Add additional nodes using the docker-compose scale command:

$ docker-compose scale paintchat=3

This will increase the total number of paintchat nodes in the cluster to 3. To confirm, click the Dashboard button in the toolbar - you should now see that the cluster size has increased from 1 to 3.

You can reduce the cluster size in the same way:

$ docker-compose scale paintchat=1

This will reduce the number of paintchat instances in the cluster to 1.

note: traefik will detect changes to the topology of the system and adjust its list of upstream hosts automatically - no configuration required!