awesome-copilot/prompts/multi-stage-dockerfile.prompt.md
James Montemagno 6fb794bc79
Update development instructions and guidelines (#29)
* Delete outdated development instructions for Next.js + Tailwind and Python; add comprehensive guidelines for PostgreSQL DBA, Angular, ASP.NET REST APIs, Azure Functions with TypeScript, Bicep, Blazor, CMake with vcpkg, C#, .NET MAUI, GenAIScript, Terraform for Azure, localization, and markdown standards.

* Update documentation and prompts for consistency and clarity

- Standardized description formatting in various markdown files to use single quotes.
- Added error handling utility in update-readme.js for safer file operations.
- Improved title extraction logic in update-readme.js to handle frontmatter more robustly.
- Updated chat modes section in README to reflect new emoji and sorted chat mode links.
- Cleaned up various instruction files for better readability and consistency.
- Ensured all markdown files end with a newline for better compatibility with version control.

* Remove standardize-frontmatter.js script

* Add usage instructions for creating and switching chat modes in README.md

* Update README.md generation script to enhance instructions and usage details for custom chat modes

* Update README.md and update-readme.js for improved instruction clarity and consistency

* Refactor README.md links and update readme script for improved clarity and consistency in instructions

* Update README.md and update-readme.js for improved instruction clarity and consistency

* Changing from a patch to regen approach for the readme

* Bit more cleanup for how to show things in the readme

* Adding missing description

* Another missing description

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Co-authored-by: Aaron Powell <me@aaron-powell.com>
2025-07-03 11:18:52 +10:00

2.3 KiB

mode tools description
agent
codebase
Create optimized multi-stage Dockerfiles for any language or framework

Your goal is to help me create efficient multi-stage Dockerfiles that follow best practices, resulting in smaller, more secure container images.

Multi-Stage Structure

  • Use a builder stage for compilation, dependency installation, and other build-time operations
  • Use a separate runtime stage that only includes what's needed to run the application
  • Copy only the necessary artifacts from the builder stage to the runtime stage
  • Use meaningful stage names with the AS keyword (e.g., FROM node:18 AS builder)
  • Place stages in logical order: dependencies → build → test → runtime

Base Images

  • Start with official, minimal base images when possible
  • Specify exact version tags to ensure reproducible builds (e.g., python:3.11-slim not just python)
  • Consider distroless images for runtime stages where appropriate
  • Use Alpine-based images for smaller footprints when compatible with your application
  • Ensure the runtime image has the minimal necessary dependencies

Layer Optimization

  • Organize commands to maximize layer caching
  • Place commands that change frequently (like code changes) after commands that change less frequently (like dependency installation)
  • Use .dockerignore to prevent unnecessary files from being included in the build context
  • Combine related RUN commands with && to reduce layer count
  • Consider using COPY --chown to set permissions in one step

Security Practices

  • Avoid running containers as root - use USER instruction to specify a non-root user
  • Remove build tools and unnecessary packages from the final image
  • Scan the final image for vulnerabilities
  • Set restrictive file permissions
  • Use multi-stage builds to avoid including build secrets in the final image

Performance Considerations

  • Use build arguments for configuration that might change between environments
  • Leverage build cache efficiently by ordering layers from least to most frequently changing
  • Consider parallelization in build steps when possible
  • Set appropriate environment variables like NODE_ENV=production to optimize runtime behavior
  • Use appropriate healthchecks for the application type with the HEALTHCHECK instruction