dockerfmt is a modern Dockerfile format and parser that enhances the functionality of the original dockfmt. This tool is built on top of the internal buildkit parser, ensuring compatibility and efficiency.

Key Features

• Advanced Formatting: Leverage the dockerfile parser from Moby's buildkit alongside the shell formatter from mvdan/sh for accurate formatting of Dockerfiles.

• Run Step Formatting: Easily format RUN steps, including support for basic heredocs, allowing for clear and organized Dockerfile commands:

  RUN <<EOF
  echo "hello"
  echo "world"
  EOF
  

• Inline Comment Support: Add inline comments in run steps to maintain code clarity:

  RUN echo "hello" \
      # this is a comment
      && echo "world"
  

  RUN echo "hello" \
      # this is a comment
      # that spans multiple lines
      && echo "world"
  

• JS Bindings: Explore the provided JavaScript bindings located in the js directory, with further details available in the README file.

Usage Instructions

To utilize dockerfmt, run the command with the following syntax:

dockerfmt [Dockerfile] [flags]
dockerfmt [command]

Available Commands:

• completion: Generate the autocompletion script for the specified shell.
• help: Assistance for any command.
• version: Display the current version number of dockerfmt.

Flags:

• -c, --check: Verify if the file(s) are formatted.
• -h, --help: Provide help information for dockerfmt.
• -i, --indent uint: Specify the number of spaces for indentation (default is 4).
• -n, --newline: Ensure the file ends with a trailing newline.
• -w, --write: Write the reformatted output back to the file(s).

Limitations

• The RUN parser does not support command grouping or semicolons.
• Long JSON commands are not subjected to line wrapping.
• The # escape=X directive is unsupported.

Contributions to the project are welcome, promoting continuous improvement and feature enhancements.