Docker Dev Skill

Triggers

• docker
• compose
• local dev
• devcontainer
• dev environment
• containerize
• dockerization

Purpose

To set up robust, reproducible local development environments using Docker technologies.

Capabilities

1. Docker Compose (Local Dev)

• Generate compose.yaml: Define services (App + DB + Redis).
• Watch Mode: Configure develop.watch for hot-reloading (sync + rebuild).
• Networking: Ensure services can talk to each other (and to host if needed).

2. DevContainers (VS Code)

• Configuration: Generate .devcontainer/devcontainer.json.
• Features: Add standard features (git, node, python, docker-in-docker).
• Extensions: Pre-install VS Code extensions for the team.

3. Optimization

• Multi-stage Builds: Separate build-deps from runtime-deps.
• Caching: Optimize layer ordering for faster builds.
• Distroless: Use distroless images for production (keep shells in dev).

Instructions

1. Prefer Compose Watch: Always recommend docker compose watch over legacy volume mounts for code sync.
2. User Mapping: Ensure file permissions work by mapping non-root user (UID/GID) inside container.
3. Persistence: Use Docker Volumes for DB data so it survives restarts.

Deliverables

• compose.yaml with watch config.
• .devcontainer/ folder.
• Dockerfile (Target: dev & prod).