A Walkthrough: User Registration and Login

In this example, we will create a simple user registration and login system using FCQRS. The system will consist of a User aggregate that handles commands for registering and logging in users. The aggregate will emit events based on the commands it processes. We will also implement a simple actor that will manage the state of the User aggregate. You can find the full sample code in the sample folder of repo.

1. Create a new F# project: dotnet new console -lang F# -n MyFCQRSApp
2. Add the packages:
   dotnet add package FCQRS
   dotnet add package Hocon.Extensions.Configuration
   dotnet add package Microsoft.Extensions.Logging.Console
   
3. Create a hocon configuration file: config.hocon
4. Create an Environments module and implement IConfiguration: and ILoggerFactory:

open Microsoft.Extensions.Configuration
open Microsoft.Extensions.Logging

type AppEnv(config: IConfiguration, loggerFactory: ILoggerFactory) =
    interface ILoggerFactory with
        member _.AddProvider(provider: ILoggerProvider) : unit = 
            loggerFactory.AddProvider provider

        member _.CreateLogger(categoryName: string) : ILogger =
            loggerFactory.CreateLogger categoryName 

        member _.Dispose() : unit = loggerFactory.Dispose()

    interface IConfiguration with
        member _.Item
            with get (key: string) = config.[key]
            and set key v = config.[key] <- v

        member _.GetChildren() = config.GetChildren()
        member _.GetReloadToken() = config.GetReloadToken()
        member _.GetSection key = config.GetSection key

Above code acts as a composition root for the application environment. It wraps IConfiguration and ILoggerFactory, allowing you to manage configuration and logging in a clean and type-safe manner.