Chat Server

A chat server based on the microservice architecture to ensure high availability, high throughput, horizontal scalability using Kafka

Architecture

Components

• Nginx: Nginx act as API gateway as well as load balancer.

  • Responsibility
    • API Gateway
    • Authentication
    • Load Balancing

• Web Socket Gateway: It's handling client websocket connection and sending message to message broker

  • Responsibility
    • Maintaining Web Socket Connection
    • Forwarding event like onConnect, onDisconnect, new-message to message broker (Kafka)
    • Sending message back to client

• Profile MS: Rest Api Service provides functionality like login, auth, contact-sync

  • Responsibility
    • Login, Auth
    • Contact Sync

• Group MS: Rest Api Service provides functionality to create, update

  • Responsibility
    • Create Group
    • Add, Remove Members
    • Fetch groups

• Session MS: Maintaining the info about which user connected to which gateway instance.

  • Responsibility
    • Maintain User connection state

• Message Router: Route the incoming new message to respective destination

  • Responsibility
    • Route 1-to-1 chat message to gateway
    • Route message to store/push notification
    • Retry failed message
    • Route group message to Group Message Router

• Group Message Router: Route the incoming group messages to respective destination

  • Responsibility
    • Route Group Message to respective destination

• Push Notification: Deliver message to user when user is offline

  • Responsibility
    • Deliver message to offline user

• Persistence Storage service: To store message until it got delivered

  • Responsibility
    • Store message new user is offline
    • Deliver message as user come online

Directory Structure

Name	Description
deployment	Deployment scripts, configurations for dev as well as prod
docs	Docs related to the project
helper	Common utility functions
libs	Project specific libs like base class for microservice, resource configuration and initialization
services	Microservice
www	Web based testing interface
.env.tmpl	Environment template file
.gitpod.Dockerfile	Docker file for gitpod setup
.gitpod.yml	Gitpod configuration file
LICENSE	Project License file (MIT)
package.json	Node project configuration file
README.md	Project description and other details

How to setup

Use Gitpod as development environment

Click on the Gitpod badge it will start the fully setup development environment.

Development environment on local machine

Prerequisites

• Apache Kafka
• Mongodb
• Nginx
• Firebase project

Steps

• Clone the master branch of the project

• Install dependencies

  npm install 
  

  Or

  yarn install 
  

• Make copy of .env.tmpl to .env and update the required variables

  cp .env.tmpl .env
  

• Initialize Kafka

  cd deployment/dev/scripts
  ./init-kafka.bash ${KAFKA_INSTALLATION_DIRECTORY} .env
  

• Open project in vscode

• Start the required microservice from RUN and DEBUG option

• (Optional) Start nginx using the configuration deployment/dev/config/nginx.config

LICENSE

MIT