Chess

Description

castling.club is a federated chess server built on the ActivityPub protocol.
It provides an open and decentralized way to play chess online, where games and moves are visible across the Fediverse.

Overview

Instead of relying on closed platforms, castling.club uses an arbiter actor (“the King”) to validate moves and mediate matches.
This ensures fair play, federation with platforms like Mastodon or Friendica, and community visibility of ongoing games.
The service runs as a lightweight Node.js app backed by PostgreSQL.

Cosmos

The diagram places Chess in the Infinito.Nexus cosmos: the components it deploys (capabilities), the central services it consumes (dependencies), and its outward reach (federation and bridged external networks).

flowchart LR
    subgraph deps [Dependencies]
        dep_svc_bkp_volume_2_local["svc-bkp-volume-2-local 💻"]
        dep_svc_db_postgres["svc-db-postgres 🐳🐝"]
        dep_svc_net_tor["svc-net-tor 🐳🐝"]
        dep_web_app_dashboard["web-app-dashboard 🐳🐝"]
        dep_web_app_keycloak["web-app-keycloak 🐳🐝"]
        dep_web_app_matomo["web-app-matomo 🐳🐝"]
        dep_web_app_prometheus["web-app-prometheus 🐳🐝"]
        dep_web_svc_css["web-svc-css 💻"]
    end
    subgraph role [web-app-chess 🐳🐝]
        svc_logout["logout ❌"]
        svc_sso["sso ❌"]
        svc_dashboard["dashboard"]
        svc_matomo["matomo"]
        svc_postgres["postgres"]
        svc_chess["chess"]
        svc_css["css"]
        svc_prometheus["prometheus"]
        svc_tor["tor"]
        svc_container_backup["container_backup"]
    end
    dep_svc_bkp_volume_2_local -. "0..1" .-> svc_container_backup
    dep_svc_db_postgres -. "0..1" .-> svc_postgres
    dep_svc_net_tor -. "0..1" .-> svc_tor
    dep_web_app_dashboard -. "0..1" .-> svc_dashboard
    dep_web_app_keycloak -- "0..0" --> svc_sso
    dep_web_app_matomo -. "0..1" .-> svc_matomo
    dep_web_app_prometheus -. "0..1" .-> svc_prometheus
    dep_web_svc_css -. "0..1" .-> svc_css
    linkStyle 4 stroke:red;

Solid 1:1 edges are fixed relationships; dashed 0..1 edges are conditional (enabled only in matching deployments); red 0..0 edges are turned off in this role. Node markers show the role's deploy modes (💻 host, 🐳 compose, 🐝 swarm); ❌ marks a service that is explicitly turned off, and ⚙️ an Ansible role dependency declared in meta/main.yml.

Features

Federated Chess Matches: Challenge and play with others across the Fediverse.
Rule Enforcement: The arbiter validates each move for correctness.
Open Identities: Use your existing Fediverse account; no new silo account needed.
Game Visibility: Matches and moves can appear in social timelines.
Lightweight Service: Built with Node.js and PostgreSQL for efficiency.

Quick Setup

Development

Clone, set up the workstation, and deploy Chess onto the local stack:

git clone https://github.com/infinito-nexus/core.git
cd core
make onboard
make compose-deploy mode=reinstall apps=web-app-chess full_cycle=false

Production

Run the published image to provision the inventory and deploy Chess to a managed server (the mounted volume persists the inventory):

APP=web-app-chess
HOST=<your-server>
DOMAIN=<your-domain>
TLS_MODE=self_signed
SSH_PUBLIC_KEY="<your-ssh-public-key>"

docker run --rm -it \
  -v "$PWD/inventories:/etc/infinito.nexus/inventories" \
  -e APP="$APP" -e HOST="$HOST" -e DOMAIN="$DOMAIN" -e TLS_MODE="$TLS_MODE" -e SSH_PUBLIC_KEY="$SSH_PUBLIC_KEY" \
  ghcr.io/infinito-nexus/core/debian bash -c '
    INVENTORY=/etc/infinito.nexus/inventories/production
    infinito administration inventory provision "$INVENTORY" \
      --inventory-file "$INVENTORY/devices.yml" \
      --host "$HOST" \
      --include "$APP" \
      --vars "{\"TLS_MODE\": \"$TLS_MODE\", \"DOMAIN_PRIMARY\": \"$DOMAIN\", \"users\": {\"administrator\": {\"authorized_keys\": [\"$SSH_PUBLIC_KEY\"]}}}" &&
    infinito administration deploy dedicated "$INVENTORY/devices.yml" \
      --password-file "$INVENTORY/.password" \
      --diff -vv'

Further Resources

Persona contract opt-outs

meta/services.yml pins sso.enabled and logout.enabled to false, and the role seeds no chess account — templates/env.j2 renders only the APP_ADMIN_URL / APP_ADMIN_EMAIL contact pair. Neither the biber nor the administrator persona has a login surface here, so templates/playwright.env.j2 declares PERSONA_BIBER_BLOCKED=true and PERSONA_ADMINISTRATOR_BLOCKED=true. The guest persona and the baseline reachability assertions run unconditionally.

Credits

Implemented by Kevin Veen-Birkenbach. Part of the Infinito.Nexus Project and maintained by Kevin Veen-Birkenbach. Licensed under the Infinito.Nexus Community License (Non-Commercial).