Opencontainers Specs

⭐️ Welcome to the Opencontainers Specs Documentation! ⭐️

This is built with vsoch/rfc-jekyll, and provides the following features:

1. You can combine many different resources across multiple repos to look like one holistic documentation base
2. Content is retrieved dynamically directly from the specs and you don't need to rebuild.
3. Adding new pages comes down to adding metadata for the pages you want.

View the specs!

Usage

1. Get the code

You can clone the repository right to where you want to host the docs:

git clone https://github.com/ ./docs
cd docs

2. Customize

Jekyll Config

To edit configuration values, customize the _config.yml. This includes details like the site title and basename.

How are documents defined?

The pages folder contains subfolders that are each examples of specs. For example, pages/images-spec includes multiple markdown files that are rendered from opencontainers/image-spec.

1. Document Metadata

The _data/specs.yaml file defines shared attributes for an entire spec folder. For example, let's take a look at this data file's definition for image-spec:

# This file holds shared metadata for a directory of specs
image-spec:
  name: Image Spec
  group: Open Containers Initiative (OCI)
  github_repo: opencontainers/image-spec
  default_version: v1.0.1
  versions:
    - v1.0.1

  # Courtesy list of pages relative to site root to link
  pages:
   - image-spec/
   - image-spec/annotations/
   - image-spec/config/
   - image-spec/considerations/
   - image-spec/conversions/
   - image-spec/descriptor/
   - image-spec/image-index/
   - image-spec/image-layout/
   - image-spec/layer/
   - image-spec/manifest/
   - image-spec/media-types/

The various urls are used to define relative paths in the repository. The list of pages (optional) will render a left side navigation to give the reader context of all the documents included for a spec. Importantly, the key image-spec at the top is used to lookup this metadata. Finally, the list of versions should correspond to releases. If a release isn't given in the browser as a variable, then we fall back to the default_version variable.

2. Document Index Page

Now we can look at an index.md in pages/image-spec/index.md that is considered the root of a spec:

---
layout: page
title: The OpenContainers Image Spec
id: IMAGE-SPEC
permalink: /image-spec/
spec: spec.md
# data key from _data/specs.yaml
key: image-spec
---

Note the key image-spec will be used for the lookup. We primarily need to know the name of the markdown file that will render into the page (spec.md) and then custom, page-specific attributes like the permalink and title.

3. Document Additional Pages

Now let's say that we have a second markdown file linked from this spec called manifest.md. The template will find these links and render them into relative urls, so we also add pages for them. In the case of manifest.md the metadata would be almost the same, but we'd update the name of the spec from spec.md to manifest.md and important we would have the permalink be a relative path to it's parent, image spec:

---
layout: page
title: The OpenContainers Image Manifest Spec
id: IMAGE-SPEC-MANIFEST
permalink: /image-spec/manifest/
spec: manifest.md
parent: image-spec
key: image-spec
---

You'll notice a new field - parent. This is here so that we can correctly format links in the correct namespace. The reason for this metadata is because we render the pages doing the following:

1. Retrieve raw markdown text from the raw_url + / + spec
2. For each image tag we find, if the url is relative, we add the raw_url so the image renders.
3. For each link that we find with a markdown file (that is not linked to another repository) we remove the .md extension and turn it into a path. This means that the final url looks like a relative path of the filename. (E.g., manifest.md linked relatively turns into manifest/ linked from the current page, or /image-spec/manifest/.

How do I add a new document?

Thus, to add a new document you should:

1. Add an entry to _data/specs.yaml
2. Add a new subfolder in pages
3. Create an index.md within using the metadata examples above. The permalink of the index should reference the root.
4. Markdown files linked from that page should be added with a permalink relative to the index, and a parent of the root.

This means that when adding a new spec, you will need to do work once to go through these steps, but then you never need to update it again. The spec will load dynamically whenever the site is needed, and there is no rebuild necessary.

How do I get help?

If you want to add a new OCI document and are having trouble, please open an issue to request it to be added.

3. Serve

Depending on how you installed jekyll:

jekyll serve
# or
bundle exec jekyll serve