computer-playbook/roles/web-app-decidim/README.md

Decidim

Description

Deploys Decidim (a free, open-source participatory democracy platform) as part of the Infinito.Nexus stack.

Overview

This role deploy Decidim, an open-source participatory democracy platform for public consultations, civic processes, community voting, and collaborative policy creation.

Cosmos

The diagram places Decidim 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_db_redis["svc-db-redis 🐳🐝"]
        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_app_seaweedfs["web-app-seaweedfs 🐳🐝"]
        dep_web_app_stalwart["web-app-stalwart 🐳🐝"]
        dep_web_svc_css["web-svc-css 💻"]
        dep_web_svc_logout["web-svc-logout 🐳🐝"]
    end
    subgraph role [web-app-decidim 🐳🐝]
        svc_sso["sso"]
        svc_logout["logout"]
        svc_dashboard["dashboard"]
        svc_matomo["matomo"]
        svc_email["email"]
        svc_postgres["postgres"]
        svc_decidim["decidim"]
        svc_redis["redis"]
        svc_css["css"]
        svc_prometheus["prometheus"]
        svc_seaweedfs["seaweedfs"]
        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_db_redis -. "0..1" .-> svc_redis
    dep_svc_net_tor -. "0..1" .-> svc_tor
    dep_web_app_dashboard -. "0..1" .-> svc_dashboard
    dep_web_app_keycloak -. "0..1" .-> svc_sso
    dep_web_app_matomo -. "0..1" .-> svc_matomo
    dep_web_app_prometheus -. "0..1" .-> svc_prometheus
    dep_web_app_seaweedfs -. "0..1" .-> svc_seaweedfs
    dep_web_app_stalwart -. "0..1" .-> svc_email
    dep_web_svc_css -. "0..1" .-> svc_css
    dep_web_svc_logout -. "0..1" .-> svc_logout

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

• Custom Docker image built on ghcr.io/decidim/decidim with OpenID Connect support
• PostgreSQL database via the shared platform instance
• Redis for caching and Action Cable
• OIDC SSO via Keycloak using omniauth_openid_connect
• Accessible at https://decidim.<your-domain>

Quick Setup

Development

Clone, set up the workstation, and deploy Decidim 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-decidim full_cycle=false

Production

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

APP=web-app-decidim
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'

SSO / Authentication

Decidim's base image does not include an OpenID Connect OmniAuth strategy. This role builds a custom image that:

• Installs the omniauth_openid_connect gem via Bundler
• Patches decidim-core's omniauth.rb initializer to register the provider gated on ENV["OIDC_ENABLED"] (Rails 7.2 no longer uses config/secrets.yml)
• Patches decidim-core's omniauth_helper.rb to return the correct icon

Credentials (OIDC_CLIENT_ID, OIDC_CLIENT_SECRET, OIDC_ISSUER) are read from env vars at runtime (never stored in the database) to avoid ActiveSupport::MessageEncryptor::InvalidMessage errors on container rebuild.

To enable SSO, set services.sso.enabled: true in your inventory.

Configuration

Key settings in meta/services.yml and meta/server.yml:

Key	Default	Description
services.sso.enabled	true	Enable Keycloak SSO via OpenID Connect
services.postgres.shared	true	Use the shared PostgreSQL service
domains.canonical	decidim.{{ DOMAIN_PRIMARY }}	Public domain

References

• Decidim documentation
• Decidim Docker image
• omniauth_openid_connect

Persona contract opt-outs

Both authenticated Playwright personas are blocked, and both are covered by bespoke tests in files/playwright/playwright.spec.js instead.

The administrator persona is blocked because Decidim's admin is a Devise account seeded by files/ruby/ensure_admin_user.rb and Devise signs in by e-mail address. The role's Playwright env therefore exposes ADMIN_EMAIL and no ADMIN_USERNAME, which is the variable the shared admin helper reads.

The biber persona logs in through OIDC without trouble; what it cannot do is log out. Decidim's sign-out is a data-method link inside the account dropdown, so the role's own tests navigate to /users/sign_out directly rather than clicking a button the shared helper could find.

Credits

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