Dev Container Setup#

Sure's dev container is the recommended way for contributors to get a fully wired local environment without manually installing PostgreSQL, Redis, or a browser driver. Opening the repo in VS Code (or a compatible editor) automatically builds the environment defined in .devcontainer/.

How It Works#

The entry point is .devcontainer/devcontainer.json, which wires three things together:

On container creation, VS Code automatically runs bundle install && npm install via postCreateCommand. After that, run bin/setup (or bin/rails db:prepare directly) to finish initializing the database.

The app service is built from .devcontainer/Dockerfile, which is based on ruby:3.4.9-slim-bookworm and pre-installs system packages for PostgreSQL (libpq-dev, postgresql-client), Node.js 20, libvips42 (ActiveStorage image variants), and ImageMagick 1.

Docker Compose Services#

All services are defined in .devcontainer/docker-compose.yml:

Environment variables are injected via two YAML anchors 2:

• x-db-env — sets POSTGRES_USER: postgres, POSTGRES_DB: postgres, POSTGRES_PASSWORD: postgres on the db container.
• x-rails-env — sets DB_HOST: db, POSTGRES_USER/PASSWORD, REDIS_URL: redis://redis:6379/1, and SELENIUM_REMOTE_URL: http://selenium:4444 on app and worker.

A named bundle_cache volume is shared between app and worker to avoid re-fetching gems 2.

The app container binds BINDING: "0.0.0.0" so the Rails server inside Docker is reachable on the host at http://localhost:3000 2.

Database Initialization#

bin/setup is the canonical first-run script. It:

1. Installs Ruby gems (bundle install) 3
2. Installs Node packages and builds design tokens (npm install && npm run tokens:build) 4
3. Runs bin/rails db:prepare to create and migrate sure_development 5
4. Clears logs/tmp and restarts the server 6

db:prepare creates the database if it does not exist, then runs pending migrations — safe to re-run. The development database defaults to sure_development via config/database.yml (overridable with POSTGRES_DB).

VS Code Extensions#

devcontainer.json automatically installs three extensions 7:

• biomejs.biome — JS/TS linter and formatter
• EditorConfig.EditorConfig — enforces project .editorconfig rules
• Shopify.ruby-extensions-pack — Ruby/Rails language support

Environment Variables#

Copy .env.local.example to .env.local before first run — referenced in the README Getting Started section. The GITHUB_TOKEN and GITHUB_USER host variables are forwarded into the container via containerEnv if present 8.

Further Reading#

• README — Local Development Setup
• VS Code Dev Containers overview (linked from README)
• Mac Dev Setup Guide / Linux / Windows wiki guides