Generate Dockerfile (Language-Aware)

Generate optimized Dockerfile and .dockerignore by detecting project language(s) and applying best practices.

Universal Docker Standards

These apply to ALL languages:

• Multi-stage builds - Separate builder and runtime stages
• Minimal runtime image - Only production dependencies
• Non-root user - Security best practice
• Entry point detection - Detect from project context
• Cache optimization - Layer ordering for fast rebuilds
• Reproducible builds - Locked dependencies

Workflow

1. Detect Project Language(s)

Glob: pyproject.toml, requirements.txt, package.json, go.mod, Cargo.toml, pom.xml, build.gradle, Gemfile

File Found	Language	Reference File
pyproject.toml or requirements.txt	Python	references/python.md
package.json	Node.js/React	references/nodejs.md
go.mod	Go	references/go.md
Cargo.toml	Rust	references/rust.md
pom.xml or build.gradle	Java	references/java.md

2. Single Language Project

If ONE language detected:

1. Read the corresponding language reference file
2. Follow its specific Dockerfile template and patterns
3. Generate Dockerfile and .dockerignore

3. Multi-Language Project

If MULTIPLE languages detected (e.g., Python backend + React frontend):

1. Read ALL relevant language reference files
2. Present user with options via AskUserQuestion:

Detected languages: Python, Node.js (React)

How should we containerize?

○ Monorepo (single Dockerfile with multi-stage for both)
○ Separate containers (Dockerfile.backend, Dockerfile.frontend)
○ Backend only (Python)
○ Frontend only (Node.js/React)

1. For monorepo approach, read references/multi-language.md for merging strategies
2. Generate appropriate Dockerfile(s)

4. No Language Detected

If no language files found:

1. Ask user via AskUserQuestion which language/framework they're using
2. Proceed with selected language reference

5. Generate .dockerignore

Universal .dockerignore (language-specific additions from reference files):

# =============================================================================
# .dockerignore - Exclude from Docker build context
# =============================================================================

# Git
.git/
.gitignore
.gitattributes

# IDE
.idea/
.vscode/
*.swp
*.swo
*~

# Local configuration (secrets)
*.env
*.env.*
!*.env.example
local.*.yaml

# Development files
Makefile.local
Makefile.deploy
tests/
docs/
*.md
!README.md

# Docker (prevent recursive context)
Dockerfile*
docker-compose*.yml
.dockerignore

# Language-specific exclusions added below
{language_specific_ignores}

6. Report

Created Docker configuration:

Language(s) detected: {languages}
Reference(s) used: {reference_files}

Dockerfile
  - Multi-stage build (builder + runtime)
  - Dependency manager: {dep_manager}
  - Non-root user configured
  - Entry point: {entry_point}

.dockerignore
  - Universal exclusions + {language}-specific

Commands:
  docker build -t myapp .           # Build image
  docker run -p 8000:8000 myapp     # Run container

Next steps:
  - Use dockercraft:compose to generate docker-compose.yml

Language Reference Files

Read these based on detected language:

• references/python.md - Python with uv, multi-stage, FastAPI/Flask patterns
• references/nodejs.md - Node.js with npm/yarn/pnpm, React/Next.js patterns
• references/go.md - Go with modules, static binary builds
• references/rust.md - Rust with cargo, musl builds
• references/java.md - Java with Maven/Gradle, JRE runtime
• references/multi-language.md - Strategies for combining languages