bot-lambda

A lightweight framework which provides an endpoint for Discord bots to respond to Discord Interactions using AWS Lambda functions.

Usage

[!TIP] Prefer a real example? Check out elliotwms/pinbot-lambda

package main

import (
	"context"

	"github.com/aws/aws-lambda-go/lambda"
	"github.com/bwmarrin/discordgo"
	"github.com/elliotwms/bot-lambda"
)

func main() {
	bot := bot_lambda.
		New([]byte("publicKey")).
		WithMessageApplicationCommand("Foo", handleFoo)

	lambda.Start(bot.HandleRequest)
}

func handleFoo(ctx context.Context, s *discordgo.Session, i *discordgo.InteractionCreate, data discordgo.ApplicationCommandInteractionData) (err error) {
	// your handler code
	return nil
}

Features

Lambda Function URL Support

Lambda functions receive different kinds of events depending on how they are invoked. bot-lambda provides a handler for both API Gateway and Function URL invocation types.

For API Gateway use HandleEvent, and for Function URLs use HandleRequest.

Configurable Interaction Router

The underlying interaction router can be configured to provide additional logging.

Built-in Ping Request Handling

bot-lambda responds to PING requests from Discord as described in the Discord documentation.

Built-in Initial Deferred Response

The endpoint can be configured to send initial deferred responses as soon as the interaction is received, which can be useful when handlers exceed the 3-second initial response time limit (this can often be the case during cold starts or if you have slower downstream dependencies).

Whilst also available in the underlying router, adding this to the Endpoint ensures this happens before other time-consuming processes such as retrieving the bot token from param store (see Session Providers).

[!WARNING] Make sure not to configure deferred responses for both the Endpoint and the underlying Router at the same time!

Public Key Verification

bot-lambda validates security headers sent by Discord as described in the documentation using the provided public key.

Session Providers

Bots will often need to use a more broadly scoped token than that provided in the interaction request for callbacks. When configured, bot-lambda replaces the discordgo.Session received by the command handler with the one resolved by the session provider.

There are a couple of built-in session providers, including retrieving the token from AWS SYstems Manager Parameter Store as used in the reference implementation. See the sessionprovider package for more info.

X-Ray Tracing

The endpoint is fully traced using Amazon X-Ray, including the Discord clients provided to the handlers. Use the context provided to continue tracing within your handlers using the X-Ray SDK.

Logging

Provide a slog logger to receive debug logs from both the Endpoint and the Router.