Awesome

go-discord-irc

Is this being maintained? Yes. But I want to merge all this functionality into the much superior matterbridge by 42wim.

This is IRC to Discord bridge was originally built for @compsoc-edinburgh and ImaginaryNet, but now it looks like more people are using it!

The IRC -> Discord side of things work as you would expect it to: messages on IRC send to Discord as the bot user, as per usual.
The Discord -> IRC side of things is a little different. On connect, this bot will join the server with the ~d, and spawn additional connections for each online person in the Discord.
Supports bidirectional PMs. (Not user friendly, but it works.)

Features

(not a full list)

Every Discord user in your server will join your channel. Messages come from those "puppets", not from a single chat bridge user.
Saying the puppet username will @ that person on Discord.
When a Discord user's presence is "offline" or "idle", their irc puppet will have their AWAY status set.
A Discord user offline for will disconnect from IRC after 24 hours (or whatever cooldown_duration you set).
Join/Quit/Part/Kick messages are sent to Discord (configurable!)
Replying to someone on Discord will prefix that someone's name, e.g. replying to Alex with "yes that's fine" will show up as <you> Alex: yes, that's fine on IRC.
IRC users can send (custom!) emoji to Discord, just do :somename:. Discord emoji shows up like that on IRC.
Reacting to a Discord message will send a CTCP ACTION (/me) on IRC.

Gotchas

Things to keep in mind in terms of functionality:

This does not work with private Discord channels properly (all discord users are added to the channel)
DO NOT USE THE SAME DISCORD BOT (API KEY) ACROSS MULTIPLE GUILDS (SERVERS).

It's built with configuration in mind, but may need a little bit of tweaking for it to work for you:

Hardcoded: Hostnames are hardcoded to follow the IPv6 IPs listed here.
Defaults aren't usable: You should set the suffix and separator config options. The default options require custom modifications to the IRC server.
Server config: This uses WEBIRC to give Discord users on IRC a distinct hostname. See here.

Configuration

The binary takes three flags:

--config filename.yaml: to pass along a configuration file containing things like passwords and channel options
--simple: to only spawn one connection (the listener will send across messages from Discord) instead of a connection per online Discord user
--debug: provide this flag to print extra debug info. Setting this flag to false (or not providing this flag) will take the value from the config file instead
--insecure: used to skip TLS verification (false = use value from settings)
--no-tls: turns off TLS

The config file is a yaml formatted file with the following fields:

name	requires restart	default	optional	description
`avatar_url`	No	`https://ui-avatars.com/api/?name=${USERNAME}`	Yes	The URL for the API to use to tell Discord what Avatar to use for a User when the user's avatar cannot be found at Discord already.
`discord_token`	Yes		No	The bot user token
`discord_message_filter`	No		Yes	Filters messages from Discord to IRC when they match.
`irc_message_filter`	No		Yes	Filters messages from IRC to Discord when they match.
`irc_server`	Yes		No	IRC server address
`irc_server_name`	Yes		No	Used as a reference when PMing from Discord to IRC. Try to use short, simple one-word names like `freenode` or `swift`
`channel_mappings`	No		No	a dict with irc channel as key (prefixed with `#`) and Discord channel ID as value
`guild_id`	No		No	the Discord guild (server) id
`irc_pass`	Yes		Yes	password for connecting to the IRC server
`suffix`	No	`~d`	Yes	appended to each Discord user's nickname when they are connected to IRC. If set to `_d2`, if the name will be `bob_d2`
`separator`	No	`_`	Yes	used in fallback situations. If set to `-`, the fallback name will be like `bob-7247_d2` (where `7247` is the discord user's discriminator, and `_d2` is the suffix)
`irc_listener_name`	Yes	`~d`	The name of the irc listener
`ignored_discord_ids`	Sometimes		Yes	A list of Discord IDs to not relay to IRC
`allowed_discord_ids`	Sometimes	`null`	Yes	A list of Discord IDs to relay to IRC. `null` allows all Discord users to be relayed to IRC. Hot reload: IDs added to the list require a presence change to take effect.
`puppet_username`	No	username of discord account being puppeted	Yes	username to connect to irc with
`webirc_pass`	No		Yes	optional, but recommended for regular (non-simple) usage. this must be obtained by the IRC sysops
`irc_listener_prejoin_commands`	Yes		Yes	list of commands for the listener IRC connection to execute (right before joining channels)
`irc_puppet_prejoin_commands`	Yes		Yes	list of commands for each Puppet IRC connection to execute (right before joining channels)
`debug`	Yes	false	Yes	debug mode
`insecure`,	Yes	false	Yes	TLS will skip verification (but still uses TLS)
`no_tls`,	Yes	false	Yes	turns off TLS
`cooldown_duration`	No	86400 (24 hours)	Yes	time in seconds for a discord user to be offline before it's puppet disconnects from irc
`show_joinquit`	No	false	yes	displays JOIN, PART, QUIT, KICK on discord
`max_nick_length`	No	30	yes	Maximum allowed nick length
`ignored_irc_hostmasks`	No		Yes	A list of IRC users identified by hostmask to not relay to Discord, uses matching syntax as in glob
`connection_limit`	Yes	0	Yes	How many connections to IRC (including our listener) to spawn (limit of 0 or less means unlimited)

The filename.yaml file is continuously read from and many changes will automatically update on the bridge. This means you can add or remove channels without restarting the bot.

An example configuration file can be seen in config.yml. Those marked as requires restart definitely require restart, but others may not currently be configured to automatically update.

This bot needs permissions to manage webhooks as it creates webhooks on the go.

https://discordapp.com/oauth2/authorize?&client_id=<YOUR_CLIENT_ID_HERE>&scope=bot&permissions=0x20000000

NEW IN 2020

Make sure you also give the bot application these intents too:

NEW IN 2022

Make sure you give the message content intent too:

Docker

First edit config.yml file to your needs. Then launch docker build -t go-discord-irc . in the repository root folder. And then docker run -d go-discord-irc to run the bot in background.

Development

A Makefile is provided to make getting started easier.

To build a binary run make build this will produce a binary of go-discord-irc in the root dir.

To build and run the binary run make run, this will use the config.yaml and start in debug.

To Execute tests run make test

Dependencies will be updated and installed with all the above commands or by running make dev