discord-bot-cdk-construct

A CDK Construct for creating a serverless Discord bot. All you need to do is supply your code to handle the commands!

Architecture Overview

This is the architecture for how this project is laid out server-side. The tools used to create these diagrams are:

• Architecture Diagrams

The bot has a fairly straightforward setup:

The biggest confusion likely stems from the use of two Lambda functions instead of one. This is to ensure that the initial request can respond within Discord's 3 second time limit and return a proper response to the user.

Sample Commands Lambda Function

For handling commands, you just need to provide a Lambda function for sending response to Discord's Web APIs. As an example of how this can be done:

import axios from 'axios';
import {Context, Callback} from 'aws-lambda';
import { DiscordEventRequest, DiscordResponseData, getDiscordSecrets} from 'discord-bot-cdk-construct';

export async function handler(event: DiscordEventRequest, context: Context,
  callback: Callback): Promise<string> {
  const response = {
    tts: false,
    content: 'Hello world!',
    embeds: [],
    allowed_mentions: [],
  };
  if (event.jsonBody.token && await sendResponse(response, event.jsonBody.token)) {
    console.log('Responded successfully!');
  } else {
    console.log('Failed to send response!');
  }
  return '200';
}

async function sendResponse(response: DiscordResponseData,
  interactionToken: string): Promise<boolean> {
  const discordSecret = await getDiscordSecrets();
  const authConfig = {
    headers: {
      'Authorization': `Bot ${discordSecret?.authToken}`
    }
  };

  try {
    let url = `https://discord.com/api/v8/webhooks/${discordSecret?.clientId}/${interactionToken}`;
    return (await axios.post(url, response, authConfig)).status == 200;
  } catch (exception) {
    console.log(`There was an error posting a response: ${exception}`);
    return false;
  }
}

A full example project utilzing this construct can be found here. Specifically, the start-api-stack.ts file uses the construct, with DiscordCommands.ts being the commands file (like shown above).

Useful commands

• npm run build compile typescript to js
• npm run watch watch for changes and compile
• npm run test perform the jest unit tests
• npm run lint perform a lint check across the code
• npm run fix-lint fix any lint issues automatically where possible
• cdk deploy deploy this stack to your default AWS account/region
• cdk diff compare deployed stack with current state
• cdk synth emits the synthesized CloudFormation template