Building a simple Discord bot using Go

This article offers tutorials on how to build a Discord `Hello World` bot using Golang.

Self made image

We will be using DiscordGo to build our very first bot, DiscordGo is a Go package that provides low level bindings to the Discord chat client API. DiscordGo has nearly complete support for all of the Discord API endpoints, WebSocket interface, and voice interface.

GitHub repository: https://github.com/bwmarrin/discordgo

First, you need to create a application by logging into your Discord developer portal.

Discord Setup Steps:

1. Redirect to : https://discord.com/developers/applications
2. Click on New Application button and provide any name to your application.
Note: The application is not the bot
3. On the left menu, select Bot and then click on Add Bot button.
4. Uncheck the public bot check box.
5. Click the Reset Token button, to generate a Token ID.
6. Go to URL Generator under OAuth2 on the left, and provide scope as Bot, and permissions such as Receive Message, Send Message, Send Message in Thread.
7. Copy the URL generated at the bottom, after the permission are set.
8. Go to that URL and add the bot to any of your server, after all these steps you should be having a Token ID and Bot(offline) in your server.

Lets now build a Hello world bot using Golang, so for that create a project with two files, main.go and bot.go

project structure

Open the terminal and intialize a module,

go mod init example.com/hello_world_bot

The go.mod file that got generated defines the module’s module path, which is also the import path used for the root directory, and its dependency requirements, which are the other modules needed for a successful build.

Next, add the DiscordGo dependency using the following command,

go get github.com/bwmarrin/discordgo

In main.go ,

package main

import bot "example.com/hello_world_bot/Bot"

func main() {
 bot.BotToken = "DISCORD TOKEN ID"
 bot.Run() // call the run function of bot/bot.go
}

In bot/bot.go ,

package bot

import (
 "fmt"
 "log"
 "os"
 "os/signal"
 "strings"

 "github.com/bwmarrin/discordgo"
)

var BotToken string

func checkNilErr(e error) {
 if e != nil {
  log.Fatal("Error message")
 }
}

func Run() {

 // create a session
 discord, err := discordgo.New("Bot " + BotToken)
 checkNilErr(err)

 // add a event handler
 discord.AddHandler(newMessage)

 // open session
 discord.Open()
 defer discord.Close() // close session, after function termination

 // keep bot running untill there is NO os interruption (ctrl + C)
 fmt.Println("Bot running....")
 c := make(chan os.Signal, 1)
 signal.Notify(c, os.Interrupt)
 <-c

}

func newMessage(discord *discordgo.Session, message *discordgo.MessageCreate) {

 /* prevent bot responding to its own message
 this is achived by looking into the message author id
 if message.author.id is same as bot.author.id then just return
 */
 if message.Author.ID == discord.State.User.ID {
  return
 }

 // respond to user message if it contains `!help` or `!bye`
 switch {
 case strings.Contains(message.Content, "!help"):
  discord.ChannelMessageSend(message.ChannelID, "Hello World😃")
 case strings.Contains(message.Content, "!bye"):
  discord.ChannelMessageSend(message.ChannelID, "Good Bye👋")
  // add more cases if required
 }

}

I have added few comments for better understanding, but most of the functions and lines are self explanatory.

Finally its time to run the bot, for that use the following command,

go run main.go

We can also first build the project and then run the executable file using following command,

go build
.\hello_world_bot.exe

When you run the project, the bot turns toonline state on discord. Just type !help or !bye and the bot should respond without error.

Output:

Bot response image

That’s pretty much all for the Hello World Discord bot. Here is a more better example of Discord Weather Bot.

GitHub - mssandeepkamath/discord-go-weather

It’s also recommended to use environment variable rather than exposing the TOKEN ID’s. Have a look at the .envfile implementation in the above example.

The article’s main goal was to show how straightforward it is to develop a simple Discord bot. I sincerely apologise if the article had any inaccuracies. If you found it helpful, kindly give it an upvote.