Eugen

Eugen is an open-source starboard bot for Discord, written in Go using bwmarrin/discordgo. Users react to messages with a star emote (⭐ by default) and, once a message reaches a configurable threshold, Eugen reposts it to a dedicated starboard channel as a nicely formatted embed.

Server configuration and starboard records are persisted in MongoDB.

Features

• Starboard — react with ⭐ and Eugen copies the message into the configured starboard channel once it hits the minimum star count. Each guild can customize:
  • the starboard channel,
  • the star emote (must be a guild emoji),
  • the minimum star threshold,
  • whether the author's own reaction counts (selfstar),
  • whether bot reactions are ignored (ignorebots),
  • the embed color.
• Per-channel star requirements — override the server-wide threshold for specific channels.
• Banned channels — prevent any of a list of channels from ever reaching the starboard.
• Blacklisted users — keep specific users off the starboard entirely.
• Interactive setup wizard — a guided, step-by-step configuration.

Commands

All commands are prefixed (defaults: e!, e., e ; the bot also responds to being mentioned).

Command	Description
ping	Checks that the bot is online and measures Discord API latency.
help [command]	Lists all visible commands, or detailed help for one.
set / set <setting> <value>	View or change the server's configuration (prefix, enabled, selfstar, ignorebots, starboard, emote, stars, color).
setup	Runs an interactive wizard to configure the starboard.
ban <channel> [...]	Bans channels from being posted to the starboard.
unban <channel> [...]	Re-allows banned channels.
blacklist <user> [...]	Blacklists users from the starboard.
unblacklist <user> [...]	Removes users from the blacklist.
req <channel> <stars|default>	Sets a custom star requirement for a channel, or resets it to the server default.
invite	Sends the bot's invite link.

Requirements

• Go 1.25 or newer
• A running MongoDB instance (local mongodb://localhost:27017 works)
• A Discord bot application + token (Discord Developer Portal) invited with the necessary intents for message content, reactions, and guilds

Running locally

1. Set up configuration

All configuration is read from environment variables or a JSON config file. There is no .env loading, so export the variables in your shell (or use a process manager such as direnv).

Required:

Variable	Description
EUGEN_BOT_TOKEN	Your Discord bot token.
EUGEN_MONGODB_URL	MongoDB connection URI (e.g. mongodb://localhost:27017).

Optional:

Variable	Description
EUGEN_DB_NAME	Database name (default: eugen).
EUGEN_DB_TIMEOUT	MongoDB connect timeout as a Go duration (default: 10s).
EUGEN_PREFIXES	Comma-separated command prefixes (default: e!,e.,e ).
EUGEN_CONFIG	Path to a JSON config file that sets the same values; env vars take precedence.

Example with a local MongoDB:

export EUGEN_BOT_TOKEN="your-bot-token"
export EUGEN_MONGODB_URL="mongodb://localhost:27017"

2. Run the bot

go run .

Or build and run the binary:

go build -o eugen .
./eugen

Mongo collections (guilds, messages) and their indexes are created automatically on startup.

Tests

The full suite (what CI runs):

go test -v -race -count=1 ./...

Note: some suites spin up a MongoDB container via testcontainers and need a local Docker daemon.

License

MIT