Chat Server

Note: This project is for my own testing and a reference for Docker scripts

Server for a chat application.

Diagram

• ChatServer
  • .NET Core Web API
• ChatBroker
  • .NET Core Web API
  • Handles new messages from RabbitMQ
• Client
  • React application
  • Send and receive messages
• RabbitMQ
  • Queue for new messages
• Redis
  • Client register
  • Has information on which server user is logged on
• TODO Postgres
  • Messages that are not delivered to offline users
• TODO Authentication
• TODO User Service
  • Node.js Express
  • Search users
  • Uses status
  • Share message history between clients

Getting Started

Run with Docker Compose

# Developemnt
$ docker-compose build
$ docker-compose up

# Production
$ docker-compose -f docker-compose-prod.yml build
$ docker-compose -f docker-compose-prod.yml up

Run development environment

Install required containers:

# Create network
$ docker network create --attachable chat

# Redis
$ docker run -d --name chat-redis --network=chat -p 6379:6379 redis

# RabbitMQ
$ docker run -d --name chat-rabbit --network=chat -p 5672:5672 -p 15672:15672 rabbitmq:3-management

# Quick start/stop
$ docker start chat-redis && docker start chat-rabbit
$ docker stop chat-redis && docker stop chat-rabbit

Start project from Visual Studio.

Run projects with Docker

Start debuggable projects in containers.

# Build image
$ docker build -t chatserver:dev .

# Start container
$ docker run --rm -it -e "Connections__Redis=chat-redis" -e "Connections__RabbitMQ=chat-rabbit" -e "DOTNET_RUNNING_IN_CONTAINER=true" -p 5000:5000 -p 10222:22 --name chat-server --network=chat -v C:\src\GitHub\chat-server\src\ChatServer:/app/ -w /app chatserver:dev

# Login to container
$ docker exec -it chat-server /bin/bash

# Start SSH server (TODO: should be always on)
$ service ssh start

# Debug -> Attach to process -> SSH (localhost:10222 root:Docker!) 
# Attach to dotnet exec process
# Select Managed Managed (.NET Core for Unix)

If you don't care about debugging from container, just start clean image with dotnet watch

$ docker run --rm -it -e "Connections__Redis=chat-redis" -e "Connections__RabbitMQ=chat-rabbit" -e "DOTNET_RUNNING_IN_CONTAINER=true" -p 5000:5000 --name chat-server --network=chat -v C:\src\GitHub\chat-server\src\ChatServer:/app/ -w /app microsoft/dotnet:2.1-sdk dotnet watch run
$ docker run --rm -it -e "Connections__Redis=chat-redis" -e "Connections__RabbitMQ=chat-rabbit" -e "DOTNET_RUNNING_IN_CONTAINER=true" -p 5000:5000 --name chat-server --network=chat -v C:\src\GitHub\chat-server\src\ChatBroker:/app/ -w /app microsoft/dotnet:2.1-sdk dotnet watch run

Debug chat-app React application with VS Code

sourceMapPathOverrides in launch.jsonmust override folder structure in Docker container.

{
  "version": "0.2.0",
  "configurations": [
    {
      "type": "chrome",
      "request": "attach",
      "name": "Attach to Chrome",
      "port": 9222,
      "webRoot": "${workspaceFolder}/src",
      "sourceMapPathOverrides": {
        "/app/src/*": "${webRoot}/*"
      }
    }
  ]
}

Production

# Build image
$ docker build -f Dockerfile-prod -t chatapp:prod .

# Start prod React app
$ docker run -it -p 800:80 --rm --name chat-app-prod chatapp:prod

TODO

• Docker doesn't set ASPNETCORE_ENVIRONMENT correctly on development compose
• Authorization
• Save messages temporarily to DB
• When user logs in send not sent messages to him immediately
• Handle same user with multiple clients on multiple servers

Notes

Redis Commander

https://www.npmjs.com/package/redis-commander

$ npm install -g redis-commander
$ redis-commander

Open: http://localhost:8081/

ChatServer

...

ChatBroker / RabbitMQ

...

ClientRegister / Redis

...

Authentication

...

Flow

# Client logs in

ChatServer: Login
 Authenticate
 Send update to client register
 Check if there is waiting messages for the client in the sent_queue

# Client sends a new message

ChatServer: New message /api/send
 Validate
 Send update to client register
 Send message to RabbitMQ

ChatBroker: New message from RabbitMQ
 Get receiver server from client register
 Save message to sent_queue
 Send to correct server /api/receive
  Success
   Remove message from sent_queue
  Fail
   Update message status to sent_queue_

ChatServer: New message /api/receive
 Send to receiver with WebSocket
 Send status to broker (success/fail)

Links

Routing

• Routes: https://docs.microsoft.com/en-us/aspnet/core/fundamentals/routing?view=aspnetcore-2.1#id7
• Route constraints: https://docs.microsoft.com/en-us/aspnet/core/fundamentals/routing?view=aspnetcore-2.1#route-constraint-reference

Performance

• https://medium.com/@tampajohn/net-core-2-and-golang-797566350095

RabbitMQ life cycle

• https://www.rabbitmq.com/dotnet-api-guide.html#connection-and-channel-lifspan

Integration tests

• https://docs.microsoft.com/en-us/aspnet/core/test/integration-tests?view=aspnetcore-2.1#customize-webapplicationfactory

Docker networking

• https://runnable.com/docker/docker-compose-networking
• https://docs.microsoft.com/en-us/dotnet/standard/microservices-architecture/multi-container-microservice-net-applications/multi-container-applications-docker-compose

Docker

• https://mherman.org/blog/dockerizing-a-react-app/#production
• https://github.com/dotnet/dotnet-docker/blob/master/samples/dotnetapp/dotnet-docker-dev-in-container.md#requirements

VS Debug

• https://blog.quickbird.uk/debug-netcore-containers-remotely-9a103060b2ff
• https://stackoverflow.com/questions/48661857/how-to-debug-a-net-core-app-runnig-in-linux-docker-container-from-visual-studio