Documentation-Requirements.md

• Introduction
• General requirements
• Linking advice
• Notes
• Warnings and other admonitions
• Files and command names
• Code blocks
• Images
• Spelling
• Names
• Version numbers
• The apostrophe

Introduction

This document outlines the requirements for all documentation in the Kata Containers project.

General requirements

All documents must:

• Be written in simple English.

• Be written in GitHub Flavored Markdown format.

• Have a .md file extension.

• Include a TOC (table of contents) at the top of the document with links to all heading sections. We recommend using the kata-check-markdown tool to generate the TOC.

• Be linked to from another document in the same repository.

  Although GitHub allows navigation of the entire repository, it should be possible to access all documentation purely by navigating links inside the documents, starting from the repositories top-level README.

  If you are adding a new document, ensure you add a link to it in the "closest" README above the directory where you created your document.

• If the document needs to tell the user to manipulate files or commands, use a code block to specify the commands.

  If at all possible, ensure that every command in the code blocks can be run non-interactively. If this is possible, the document can be tested by the CI which can then execute the commands specified to ensure the instructions are correct. This avoids documents becoming out of date over time.

Linking advice

Linking between documents is strongly encouraged to help users and developers navigate the material more easily. Linking also avoids repetition - if a document needs to refer to a concept already well described in another section or document, do not repeat it, link to it (the DRY principle).

Another advantage of this approach is that changes only need to be applied in one place: where the concept is defined (not the potentially many places where the concept is referred to using a link).

Notes

Important information that is not part of the main document flow should be added as a Note in bold with all content contained within a block quote:

Note: This is a really important point!

This particular note also spans multiple lines. The entire note should be included inside the quoted block.

If there are multiple notes, bullets should be used:

Notes:

• I am important point 1.

• I am important point 2.

• I am important point n.

Warnings and other admonitions

Use the same approach as for notes. For example:

Warning: Running this command assumes you understand the risks of doing so.

Other examples:

Warnings:

• Do not unplug your computer!
• Always read the label.
• Do not pass go. Do not collect $200.

Tip: Read the manual page for further information on available options.

Hint: Look behind you!

Files and command names

All filenames and command names should be rendered in a fixed-format font using backticks:

Run the foo command to make it work.

Modify the bar option in file /etc/baz/baz.conf.

Render any options that need to be specified to the command in the same manner:

Run bar -axz --apply foo.yaml to make the changes.

For standard system commands, it is also acceptable to specify the name along with the manual page section that documents the command in brackets:

The command to list files in a directory is called ls(1).

Code blocks

This section lists requirements for displaying commands and command output.

The requirements must be adhered to since documentation containing code blocks is validated by the CI system, which executes the command blocks with the help of the doc-to-script utility.

• If a document includes commands the user should run, they MUST be shown in a bash code block with every command line prefixed with $ to denote a shell prompt:

      ```bash
      $ echo "Hi - I am some bash code"
      $ sudo docker run -ti busybox true
      $ [ $? -eq 0 ] && echo "success"
      ```
  
  

• If a command needs to be run as the root user, it must be run using sudo(8).

  $ sudo echo "I'm running as root"

• All lines beginning # should be comment lines, NOT commands to run as the root user.

• Try to avoid showing the output of commands.

  The reasons for this:

  • Command output can change, leading to confusion when the output the user sees does not match the output in the documentation.

  • There is the risk the user will get confused between what parts of the block refer to the commands they should type and the output that they should not.

  • It can make the document look overly "busy" or complex.

  In the unusual case that you need to display command output, use an unadorned code block (```):

      The output of the `ls(1)` command is expected to be:
  
      ```
      ls: cannot access '/foo': No such file or directory
      ```
  
  

• Long lines should not span across multiple lines by using the \ continuation character.

  GitHub automatically renders such blocks with scrollbars. Consequently, backslash continuation characters are not necessary and are a visual distraction. These characters also mess up a user's shell history when commands are pasted into a terminal.

Images

All binary image files must be in a standard and well-supported format such as PNG. This format is preferred for vector graphics such as diagrams because the information is stored more efficiently, leading to smaller file sizes. JPEG images are acceptable, but this format is more appropriate to store photographic images.

When possible, generate images using freely available software.

Every binary image file MUST be accompanied by the "source" file used to generate it. This guarantees that the image can be modified by updating the source file and re-generating the binary format image file.

Ideally, the format of all image source files is an open standard, non-binary one such as SVG. Text formats are highly preferable because you can manipulate and compare them with standard tools (e.g. diff(1)).

Spelling

Since this project uses a number of terms not found in conventional dictionaries, we have a spell checking tool that checks both dictionary words and the additional terms we use.

Run the spell checking tool on your document before raising a PR to ensure it is free of mistakes.

If your document introduces new terms, you need to update the custom dictionary used by the spell checking tool to incorporate the new words.

Names

Occasionally documents need to specify the name of people. Write such names in backticks. The main reason for this is to keep the spell checker happy (since it cannot manage all possible names). However, since backticks render in a fixed-width font, this makes the names clearer:

Welcome to Clark Kent, the newest member of the Kata Containers Architecture Committee.

Version numbers

Write version number in backticks. This keeps the spell checker happy and since backticks render in a fixed-width font, it also makes the numbers clearer:

Ensure you are using at least version 1.2.3-alpha3.wibble.1 of the tool.

The apostrophe

The apostrophe character (') must only be used for showing possession ("Peter's book") and for standard contractions (such as "don't").

Use double-quotes ("...") in all other circumstances you use quotes outside of code blocks.