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. If shared/ is missing, fetch files via WebFetch from https://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/Dockerfile

• Dockerfile.backend -> project root

• docker-compose.yml -> project root

• .dockerignore -> project root

• nginx.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 config validates 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