Yuki Bot

Development Setup

Prerequisites

You will need to create your own Discord bot for testing changes during local development. Log in to the Discord developer portal and create a new application. Enable the bot user and copy the token provided. Add your bot to a server you'd like to use for testing.

The following commands should be ran from inside the project directory:

cd YukiBot

Create a local environment configuration:

cp .env.example .env

Update the new file with your own Discord Bot token to enable testing.

Running the Application

Start the application using Docker:

docker compose up -d

Note that it may take a few minutes for the CosmosDB emulator container to start up.

You may need to restore packages after starting the containers since they are included in the volume mount:

dotnet restore

Architecture

Yuki is built on top of Discord.NET with an architecture inspired by ASP.NET Core that leans heavily on Dependency Injection (DI). The entrypoint to the application is Program.cs which creates then runs a bot client using ClientBuilder.

Services

Services are added to the DI container using the ClientBuilder.ConfigureServices method. In order to function, an IClientToken service must be registered. This service provides the client with the secret bot token used to authenticate with Discord's gateway API. In the case of Yuki, the AddConfigService extension method handles registration of the IClientToken service using the token available in the Environment.

In addition to the services added in the call to ClientBuilder.ConfigureServices, an instance of IDiscordClient is always available for injection and can be used to interact with the Discord API when there isn't any existing context available.

Components

Components are the building blocks of the Discord bot. They are special services that implement specific interfaces and are added to the client using ClientBuilder.AddComponent. There are currently two interfaces that can be implemented to define a component.

Jobs (IJob)

A Job is a component that implements the IJob interface. A Job runs a method OnJobTriggered on a specified interval Interval.

Message Handlers (IMessageHandler)

A Message Handler is a component that implements the IMessageHandler interface. A Message Handler runs a method OnMessageReceiveAsync whenever the bot receives a message from another user. A message object is passed to the method as a parameter.

Database

Yuki uses Azure's CosmosDB, a document DB that's easy to query and doesn't require strict pre-defined schemas. Entities stored in the database are written under Models/ and extend the CosmosModel abstract class. Database operations are performed through CosmosService which provides methods for fetching and updating documents. Documents in the database are tagged with their type name so they can be filtered and deserialized to explicit, statically typed classes. This is handled automatically by CosmosService and CosmosModel.