DiscordTypescriptLambda

This is a template repository to quickly and easily get your discord bot running, most likely for free due to the extremely low operation costs of running on AWS Lambda.

Why Use This?

• AWS Lambda is incredibly cheap to run. Under the free tier, you get 1 million free invocations per month, which corresponds to 1 million bot interactions each month. Even after you exceed this limit, it only costs you $0.20 USD to run another million interactions!
• Local development is supported by this template, which is the easiest way to rapidly develop your bot on a testing server
• We use CDK for infrastructure, which is a very powerful and accessible way to edit the stack, especially when compared to raw CloudFormation templates
• Typescript provides you with incredible type safety, and will help you catch errors early on

Installation

• Click "Use this template" on GitHub
• Clone the generated repository
• cd into the repository
• Run npm install

Adding Commands

• For each command you want to add (each /slash command), create a new file in lib/commands. You may want to copy hello.ts.
• In the constructor, modify the command metadata using the following options.
• In the run() method, implement how to actually handle the command when it is executed
• Whenever you add a command, you must register it by first importing it, and then including the class in lib/common.ts (at the bottom).

Local Development

• It's much easier to test out your bot locally than to test it on AWS Lambda
• To test, first export the following variables:
  • DISCORD_APP_ID: the "Application ID" of your app, listed on the "General Information" page of the Discord Developer Dashboard.
  • DISCORD_PUBLIC_KEY: the "Public Key" of your app, listed in the same place.
  • DISCORD_BOT_TOKEN: listed on the "Bot" page of the dashboard.
  • DISCORD_GUILD_ID: this is the ID of the server in which you are testing the bot. If you enable discord developer mode, you can get this by right-clicking any server and clicking "Copy ID".
• Then run npm run dev

Deploying to Lambda

• Once you are happy with your bot, get ready to deploy to AWS.
• Export the following variables:
  • DISCORD_APP_ID: the "Application ID" of your app, listed on the "General Information" page of the Discord Developer Dashboard.
  • DISCORD_PUBLIC_KEY: the "Public Key" of your app, listed in the same place.
  • AWS_PROFILE: an AWS profile that has permissions to deploy a CloudFormation stack (e.g. the root account credentials)
• Run npm run deploy
• Copy the CdkStack.discordEndpoint URL printed in the terminal, and paste it into the field labelled "INTERACTIONS ENDPOINT URL" on the Discord dashboard

Adding Additional Infrastructure

• This template is designed to be fully extensible, in case you need to add infrastructure such as a database to your app.
• To do this open lib/cdk-stack.ts
• For example, to add a DynamoDB (which is easily the cheapest way to add persistent storage), add the following to the bottom of the cdk-stack.ts:

import * as dynamodb from "aws-cdk-lib/aws-dynamodb";

const handler: lambda.NodejsFunction;

const table = new dynamodb.Table(this, "Table", {
  partitionKey: { name: "id", type: dynamodb.AttributeType.STRING },
});

table.grantFullAccess(handler);

Setup Actions

• Your bot may need to run certain actions when it is first deployed.
• For example, if you have added a database you may need to "seed" it with initial data.
• By default the only setup action run in this template is to sync the commands with the Discord API.
• However if you want to add new actions, simply edit lib/setup.ts and add additional AWS