What is this?

This repository contains the image documentation for each of the official images. See docker-library/official-images for more information about the program in general.

All Markdown files here are run through tianon's fork of markdownfmt, and verified as formatted correctly via GitHub Actions.

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Table of Contents

1. What is this?
   1. Table of Contents
2. How do I update an image's docs
3. How do I add a new image's docs
4. Files related to an image's docs
   1. folder <image name>
   2. README.md
   3. content.md
   4. README-short.txt
   5. logo.png
   6. license.md
   7. maintainer.md
   8. github-repo
   9. user-feedback.md
5. Files for main Docs repo
   1. update.sh
   2. generate-repo-stub-readme.sh
   3. push.pl
   4. .template-helpers/generate-dockerfile-links-partial.sh
   5. .template-helpers/template.md and .template-helpers/user-feedback.md
6. Issues and Contributing

How do I update an image's docs

Edit the content.md for an image; not the README.md as it's auto-generated from the contents of the other files in that repo. To see the changes to the README.md, run ./update.sh myimage from the repo root, but do not add the README.md changes to your pull request. See also markdownfmt.sh point below.

After opening your Pull Request the changes will be checked by an automated markdownfmt.sh before it can be merged. A common issue is incorrect spacing such as with two lines missing an empty line between them (double-spaced).

How do I add a new image's docs

• create a folder for my image: mkdir myimage
• create a README-short.txt (required, 100 char max)
• create a content.md (required)
• create a license.md (required)
• create a maintainer.md (required)
• create a github-repo (required)
• add a logo.png (recommended)

Optionally:

• run ./markdownfmt.sh -l myimage to verify whether format of your markdown files is compliant to tianon/markdownfmt. In case you see any file names, markdownfmt detected some issues, which might result in a failed build during continuous integration. run ./markdownfmt.sh -d myimage to see a diff of changes required to pass.
• run ./update.sh myimage to generate myimage/README.md for manual review of the generated copy.
  Note: do not actually commit the README.md file; it is automatically generated/committed before being uploaded to Docker Hub.

Files related to an image's docs

folder <image name>

This is where all the partial and generated files for a given image reside, (ex: golang/).

README.md

This file is generated using update.sh.

content.md

This file contains the main content of your image's long description. The basic parts you should have are a "What Is" section and a "How To" section. See the doc on Official Repos for more information on long description. The issues and contribution section is generated by the script but can be overridden. The following is a basic layout:

# What is XYZ?

// about what the contained software is

%%LOGO%%

# How to use this image

// descriptions and examples of common use cases for the image
// make use of subsections as necessary

README-short.txt

This is the short description for the docker hub, limited to 100 characters in a single line.

Go (golang) is a general purpose, higher-level, imperative programming language.

logo.png

Logo for the contained software. While there are not hard rules on formatting, most existing logos are square or landscape and stay within a few hundred pixels of width.

license.md

This file should contain a link to the license for the main software in the image. Here is an example for golang:

View [license information](http://golang.org/LICENSE) for the software contained in this image.

maintainer.md

This file should contain a link to the maintainers of the Dockerfile.

github-repo

This file should contain the URL to the GitHub repository for the Dockerfiles that become the images. The file should be in a single line ending in a newline with no extraneous whitespace. Only one GitHub repo per image repository is supported. It is used in generating links. Here is an example for golang:

https://github.com/docker-library/golang

user-feedback.md

This file is an optional override of the default user-feedback.md for those repositories with different issue and contributing policies.

Files for main Docs repo

update.sh

This is the main script used to generate the README.md files for each image. The generated file is committed along with the files used to generate it (see below on what customizations are available). Accepted arguments are which image(s) you want to update or no arguments to update all of them.

This script assumes bashbrew is in your PATH (for scraping relevant tag information from the library manifest file for each repository).

generate-repo-stub-readme.sh

This is used to generate a simple README.md to put in the image's repo. Argument is the name of the image, like golang and it then outputs the readme to standard out.

push.pl

This is used by us to push the actual content of the READMEs to the Docker Hub as special access is required to modify the Hub description contents.

.template-helpers/generate-dockerfile-links-partial.sh

This script is used by update.sh to create the "Supported tags and respective Dockerfile links" section of each generated README.md from the information in the official-images library/ manifests.

.template-helpers/template.md and .template-helpers/user-feedback.md

These files are the templates used in building the <image name>/README.md file, in combination with the individual image's files.

Issues and Contributing

If you would like to make a new Official Image, be sure to follow the guidelines.

Feel free to make a pull request for fixes and improvements to current documentation. For questions or problems on this repo come talk to us via the #docker-library IRC channel on Freenode or open up an issue.