Paths: File paths (shared/,references/,../ln-*) are relative to skills repo root. If not found at CWD, locate this SKILL.md directory and go up one level for repo root. Ifshared/is missing, fetch files via WebFetch fromhttps://raw.githubusercontent.com/levnikolaevich/claude-code-skills/master/skills/{path}.
ln-731-docker-generator
Type: L3 Worker Category: 7XX Project Bootstrap
Generates production-ready Docker configuration for containerized development.
Purpose & Scope
Creates Docker infrastructure for local development and production:
- Does: Generate Dockerfiles, docker-compose,.dockerignore, nginx config
- Does NOT: Build images, start containers, manage deployments
Inputs
| Input | Source | Description |
|---|---|---|
| Stack Type | ln-730 coordinator | frontend, backend-dotnet, backend-python |
| Versions | Auto-detected | Node.js,.NET, Python versions |
| Project Name | Directory name | Used for container naming |
| Ports | Defaults or detected | Frontend: 3000, Backend: 5000/8000, DB: 5432 |
Outputs
| File | Purpose | Template |
|---|---|---|
Dockerfile.frontend | Frontend build & serve | dockerfile_frontend.template |
Dockerfile.backend | Backend build & run | dockerfile_backend_dotnet.template or dockerfile_backend_python.template |
docker-compose.yml | Service orchestration | docker_compose.template |
.dockerignore | Build context exclusions | dockerignore.template |
nginx.conf | Frontend proxy config | nginx.template |
Workflow
Phase 1: Input Validation
Validate received configuration from coordinator:
- Check stack type is supported (frontend, backend-dotnet, backend-python)
- Verify versions are valid (Node 18+,.NET 8+, Python 3.10+)
- Confirm project directory exists
Output: Validated configuration or error
Phase 2: Template Selection
Select appropriate templates based on stack:
| Stack | Templates Used |
|---|---|
| Frontend only | dockerfile_frontend, nginx, dockerignore |
| Backend.NET | dockerfile_backend_dotnet, docker_compose, dockerignore |
| Backend Python | dockerfile_backend_python, docker_compose, dockerignore |
| Full stack.NET | All of the above (dotnet variant) |
| Full stack Python | All of the above (python variant) |
Phase 3: Variable Substitution
Replace template variables with detected values:
| Variable | Source | Example |
|---|---|---|
{{NODE_VERSION}} | package.json engines or default | 22 |
{{DOTNET_VERSION}} | *.csproj TargetFramework | 9.0 |
{{PYTHON_VERSION}} | pyproject.toml or default | 3.12 |
{{PROJECT_NAME}} | Directory name | my-app |
{{DLL_NAME}} | *.csproj AssemblyName | MyApp.Api.dll |
{{FRONTEND_PORT}} | Default or detected | 3000 |
{{BACKEND_PORT}} | Stack-dependent | 5000 (.NET), 8000 (Python) |
{{BACKEND_HOST}} | Service name | backend |
{{CMD}} | Framework-dependent | ["uvicorn", "main:app", "--host", "0.0.0.0", "--port", "8000"] (FastAPI) or ["gunicorn", "--bind", "0.0.0.0:8000", "{{PROJECT_NAME}}.wsgi:application"] (Django) |
Phase 4: File Generation
Generate files from templates:
- Check if file already exists (warn before overwrite)
- Apply variable substitution
- Write file to appropriate location
- Validate syntax where possible
File Locations:
Dockerfile.frontend->src/frontend/DockerfileDockerfile.backend-> project rootdocker-compose.yml-> project root.dockerignore-> project rootnginx.conf->src/frontend/nginx.conf
Supported Stacks
Frontend: React/Vite + Nginx
Requirements:
- package.json with build script
- Vite or CRA configuration
Generated:
- Multi-stage Dockerfile (builder + nginx)
- Nginx config with SPA routing and API proxy
Backend:.NET 8/9
Requirements:
- *.sln file in root
- *.csproj with TargetFramework
Generated:
- Multi-stage Dockerfile (SDK build + ASP.NET runtime)
- Health check endpoint configuration
Backend: Python (FastAPI/Django)
Requirements:
- requirements.txt or pyproject.toml
Generated:
- Multi-stage Dockerfile (builder + slim runtime)
- uvicorn (FastAPI) or gunicorn (Django) entrypoint
Security & Performance Best Practices
All generated files follow these guidelines:
| Practice | Implementation |
|---|---|
| Non-root user | Create and use appuser (UID 1001) |
| Minimal images | Alpine/slim variants |
| Multi-stage builds | Exclude build tools from runtime |
| No secrets | Use environment variables, not hardcoded |
| Health checks | Built-in HEALTHCHECK instructions (wget/curl) |
| Specific versions | Pin base image versions (e.g., nginx:1.27-alpine) |
| Non-interactive mode | ARG DEBIAN_FRONTEND=noninteractive |
| Layer caching | Copy dependency files first, source code last |
| BuildKit cache | Use --mount=type=cache for pip |
| Python optimization | PYTHONDONTWRITEBYTECODE=1, PYTHONUNBUFFERED=1 |
Quality Criteria
Generated files must meet:
docker-compose configvalidates without errors- All base images use specific versions (not
latest) - Non-root user configured in all Dockerfiles
- Health checks present for all services
- .dockerignore excludes all sensitive files
- No hardcoded secrets or passwords
Critical Notes
- Version Detection: Use detected versions from coordinator, not hardcoded defaults.
- Idempotent: Check file existence before writing. Warn if overwriting.
- Template-based: All generation uses templates from references/. Do NOT hardcode file contents.
- Security First: Every generated file must follow security best practices.
Reference Files
| File | Purpose |
|---|---|
| dockerfile_frontend.template | React/Vite multi-stage Dockerfile |
| dockerfile_backend_dotnet.template | .NET multi-stage Dockerfile |
| dockerfile_backend_python.template | Python multi-stage Dockerfile |
| docker_compose.template | docker-compose.yml template |
| dockerignore.template | .dockerignore template |
| nginx.template | Nginx configuration |
Definition of Done
- Dockerfiles generated for all detected stack components (frontend/backend)
- docker-compose.yml validates without errors (
docker-compose config) - .dockerignore excludes sensitive files and build artifacts
- All base images use pinned versions (not
latest)
Version: 1.2.0 Last Updated: 2026-01-21