Li Li

lilibot

A Discord bot that shares out the seats in a game group capped at 5 players.
Runs on Google Cloud Run for $0/month.

What it does

Opens a sign-up, people join with a button, and when it closes it draws at random who sits out — remembering last round's leftovers so the same people don't always miss out.

/rotacion posts a sign-up with Apuntarme, Salir and Cerrar convocatoria
Each person counts once, however many times they click
It closes on a timer or on the button, whichever comes first
5 or fewer signed up → everybody plays, no rotation
More than 5 → the excess are drawn at random, but anyone benched last round has a guaranteed seat and is not entered into the draw
This round's nominees are next round's immune players — that handover is the whole rotation

Memory is per channel. The full rules, including what happens when more than five players are owed a seat, are in the architecture guide.

Architecture

flowchart LR
  user([Discord user]) -->|/rotacion · buttons| discord[Discord]
  discord -->|POST /interactions<br/>Ed25519 signed| run[Cloud Run · scales to zero]
  run -->|read / write state| store[(Firestore<br/>rotations/channelId)]
  run -->|post · edit messages| discord
  run -->|schedule the close| tasks[Cloud Tasks]
  tasks -->|POST /close at closesAt| run

There is no gateway and no WebSocket — Discord calls the bot, not the other way round. Nothing stays running between sign-ups, which is what makes it free, and also why joining is a button rather than a reaction: reactions are gateway-only events.

Zero runtime dependencies. Node 24's WebCrypto covers Ed25519, fetch covers the rest, and type stripping means no build step. Boot is ~85 ms, against Discord's 3-second response deadline. The reasoning is in Architecture, along with how to add a feature.

Commands

Command	What it does
`pnpm test`	The full suite, 70 tests
`pnpm typecheck`	`tsc --noEmit`
`pnpm dev`	Runs the server with `--watch`, reading `.env`
`pnpm commands`	Registers the `/rotacion` slash command with Discord
`./deploy/provision.sh`	Creates the GCP infrastructure, once
`./deploy/deploy.sh`	Builds and deploys to Cloud Run

Configuration

Copy env.example to .env for local work. In production Cloud Run injects these: the two secrets from Secret Manager, the rest as plain variables.

Variable	Required	Default	What it is
`DISCORD_TOKEN`	yes	—	Bot token (secret)
`DISCORD_PUBLIC_KEY`	yes	—	Public key used to verify signatures
`APPLICATION_ID`	yes	—	Discord application ID
`GUILD_ID`	no	global	Server to register the command in
`GCP_PROJECT`	yes	—	Project ID (`GOOGLE_CLOUD_PROJECT` also works)
`SERVICE_URL`	yes	—	The service's public URL; Cloud Tasks calls `${SERVICE_URL}/close`
`TASKS_LOCATION`	no	`us-east1`	Queue region
`TASKS_QUEUE`	no	`lilibot-close`	Queue name
`PORT`	no	`8080`	Listening port

Where each key comes from is in Discord setup.

Documentation