SR Messaging

Objective

The purpose of this exercise is to implement a messaging service meeting the following requirements :

• If client A sends a message M to client B and B is known by the service, the service should deliver M to B
• The client should be implemented in a web browser (very basic HTML + JS)
• The implementation technology is open: any language or middleware (databases, messaging system…) can be used (Golang and Python are preferred though). However, if a third-party system is used, the implementation must include a standalone version. To sum up, this problem can be reduced to a simple directed/targeted chat service

Prerequisites

This project use :

• golang
• docker-compose

Architecture

The message distribution is done using Kafka :

• User A connects through browser using websocket and is given a unique ID
• User A sent message to another user B
• Received message is sent to Kafka
• Message is consumed and routed to user B

Building

make clean build

Testing

make test

Running

Run docker-compose

make run

CLI usage

Instead of make run, you can build or install the go binary and then use the provided command line interface.

Run the server

Usage:
  srmessaging run [flags]

Flags:
  -b, --broker string     Message broker endpoint (default "localhost:9092")
  -e, --endpoint string   HTTP endpoint to listen to (default ":8080")
  -h, --help              help for run

How to test the app

• run the backend as seen above
• open two tabs for user A & B with the test webpage (see project https://github.com/esys/srmessaging-ui)
• in tab A : fill in the "Send To" field with the user B id
• in tab A : enter a message and press send
• in tab B : received message is displayed at the bottom