Documentation styleguide

This styleguide recommends best practices to improve documentation and to keep it organized and easy to find.

Location and naming of documents

Note: These guidelines derive from the discussion taken place in issue #3349.

The documentation hierarchy can be vastly improved by providing a better layout and organization of directories.

Having a structured document layout, we will be able to have meaningful URLs like docs.gitlab.com/user/project/merge_requests.html. With this pattern, you can immediately tell that you are navigating a user related documentation and is about the project and its merge requests.

The table below shows what kind of documentation goes where.

Directory	What belongs here
`doc/user/`	User related documentation. Anything that can be done within the GitLab UI goes here including `/admin`.
`doc/administration/`	Documentation that requires the user to have access to the server where GitLab is installed. The admin settings that can be accessed via GitLab's interface go under `doc/user/admin_area/`.
`doc/api/`	API related documentation.
`doc/development/`	Documentation related to the development of GitLab. Any styleguides should go here.
`doc/legal/`	Legal documents about contributing to GitLab.
`doc/install/`	Probably the most visited directory, since `installation.md` is there. Ideally this should go under `doc/administration/`, but it's best to leave it as-is in order to avoid confusion (still debated though).
`doc/update/`	Same with `doc/install/`. Should be under `administration/`, but this is a well known location, better leave as-is, at least for now.

General rules:

The correct naming and location of a new document, is a combination of the relative URL of the document in question and the GitLab Map design that is used for UX purposes (source, image).
When creating a new document and it has more than one word in its name, make sure to use underscores instead of spaces or dashes (-). For example, a proper naming would be import_projects_from_github.md. The same rule applies to images.
There are four main directories, user, administration, api and development.
The doc/user/ directory has five main subdirectories: project/, group/, profile/, dashboard/ and admin_area/.
1. doc/user/project/ should contain all project related documentation.
2. doc/user/group/ should contain all group related documentation.
3. doc/user/profile/ should contain all profile related documentation. Every page you would navigate under /profile should have its own document, i.e. account.md, applications.md, emails.md, etc.
4. doc/user/dashboard/ should contain all dashboard related documentation.
5. doc/user/admin_area/ should contain all admin related documentation describing what can be achieved by accessing GitLab's admin interface (not to be confused with doc/administration where server access is required).
  1. Every category under /admin/application_settings should have its own document located at doc/user/admin_area/settings/. For example, the Visibility and Access Controls category should have a document located at doc/user/admin_area/settings/visibility_and_access_controls.md.

If you are unsure where a document should live, you can ping @axil in your merge request.

Text

Split up long lines, this makes it much easier to review and edit. Only double line breaks are shown as a full line break in GitLab markdown. 80-100 characters is a good line length
Make sure that the documentation is added in the correct directory and that there's a link to it somewhere useful
Do not duplicate information
Be brief and clear
Unless there's a logical reason not to, add documents in alphabetical order
Write in US English
Use single spaces instead of double spaces

Formatting

Use dashes (-) for unordered lists instead of asterisks (*)
Use the number one (1) for ordered lists
Use underscores (_) to mark a word or text in italics
Use double asterisks (**) to mark a word or text in bold
When using lists, prefer not to end each item with a period. You can use them if there are multiple sentences, just keep the last sentence without a period

Headings

Add only one H1 title in each document, by adding # at the beginning of it (when using markdown). For subheadings, use ##, ### and so on
Avoid putting numbers in headings. Numbers shift, hence documentation anchor links shift too, which eventually leads to dead links. If you think it is compelling to add numbers in headings, make sure to at least discuss it with someone in the Merge Request
When introducing a new document, be careful for the headings to be grammatically and syntactically correct. It is advised to mention one or all of the following GitLab members for a review: @axil, @rspeicher, @dblessing, @ashleys. This is to ensure that no document with wrong heading is going live without an audit, thus preventing dead links and redirection issues when corrected
Leave exactly one newline after a heading

Links

If a link makes the paragraph to span across multiple lines, do not use the regular Markdown approach: [Text](https://example.com). Instead use [Text][identifier] and at the very bottom of the document add: [identifier]: https://example.com. This is another way to create Markdown links which keeps the document clear and concise. Bonus points if you also add an alternative text: [identifier]: https://example.com "Alternative text" that appears when hovering your mouse on a link

Images

Place images in a separate directory named img/ in the same directory where the .md document that you're working on is located. Always prepend their names with the name of the document that they will be included in. For example, if there is a document called twitter.md, then a valid image name could be twitter_login_screen.png.
Images should have a specific, non-generic name that will differentiate them.
Keep all file names in lower case.
Consider using PNG images instead of JPEG.

Inside the document:

The Markdown way of using an image inside a document is: ![Proper description what the image is about](img/document_image_title.png)
Always use a proper description for what the image is about. That way, when a browser fails to show the image, this text will be used as an alternative description
If there are consecutive images with little text between them, always add three dashes (---) between the image and the text to create a horizontal line for better clarity
If a heading is placed right after an image, always add three dashes (---) between the image and the heading

Notes

Notes should be quoted with the word Note: being bold. Use this form:
```
>**Note:**
This is something to note.
```
which renders to:

Note: This is something to note.

If the note spans across multiple lines it's OK to split the line.

New features

Every piece of documentation that comes with a new feature should declare the GitLab version that feature got introduced. Right below the heading add a note:
```
> Introduced in GitLab 8.3.
```
If possible every feature should have a link to the MR that introduced it. The above note would be then transformed to:
```
> [Introduced][ce-1242] in GitLab 8.3.
```
, where the link identifier is named after the repository (CE) and the MR number.
If the feature is only in GitLab Enterprise Edition, don't forget to mention it, like:
```
> Introduced in GitLab Enterprise Edition 8.3.
```
Otherwise, leave this mention out.

References

GitLab Restart: There are many cases that a restart/reconfigure of GitLab is required. To avoid duplication, link to the special document that can be found in doc/administration/restart_gitlab.md. Usually the text will read like:
```
Save the file and [reconfigure GitLab](../administration/restart_gitlab.md)
for the changes to take effect.
```
If the document you are editing resides in a place other than the GitLab CE/EE doc/ directory, instead of the relative link, use the full path: http://docs.gitlab.com/ce/administration/restart_gitlab.html. Replace reconfigure with restart where appropriate.

Installation guide

Ruby: In step 2 of the installation guide, we install Ruby from source. Whenever there is a new version that needs to be updated, remember to change it throughout the codeblock and also replace the sha256sum (it can be found in the downloads page of the Ruby website).

Changing document location

Changing a document's location is not to be taken lightly. Remember that the documentation is available to all installations under help/ and not only to GitLab.com or http://docs.gitlab.com. Make sure this is discussed with the Documentation team beforehand.

If you indeed need to change a document's location, do NOT remove the old document, but rather put a text in it that points to the new location, like:

This document was moved to [path/to/new_doc.md](path/to/new_doc.md).

where path/to/new_doc.md is the relative path to the root directory doc/.

For example, if you were to move doc/workflow/lfs/lfs_administration.md to doc/administration/lfs.md, then the steps would be:

Copy doc/workflow/lfs/lfs_administration.md to doc/administration/lfs.md

Replace the contents of doc/workflow/lfs/lfs_administration.md with:

This document was moved to [administration/lfs.md](../../administration/lfs.md).

Find and replace any occurrences of the old location with the new one. A quick way to find them is to use git grep. First go to the root directory where you cloned the gitlab-ce repository and then do:
```
git grep -n "workflow/lfs/lfs_administration"
git grep -n "lfs/lfs_administration"
```

Things to note:

Since we also use inline documentation, except for the documentation itself, the document might also be referenced in the views of GitLab (app/) which will render when visiting /help, and sometimes in the testing suite (spec/).
The above git grep command will search recursively in the directory you run it in for workflow/lfs/lfs_administration and lfs/lfs_administration and will print the file and the line where this file is mentioned. You may ask why the two greps. Since we use relative paths to link to documentation, sometimes it might be useful to search a path deeper.
The *.md extension is not used when a document is linked to GitLab's built-in help page, that's why we omit it in git grep.

Configuration documentation for source and Omnibus installations

GitLab currently officially supports two installation methods: installations from source and Omnibus packages installations.

Whenever there is a setting that is configurable for both installation methods, prefer to document it in the CE docs to avoid duplication.

Configuration settings include:

settings that touch configuration files in config/
NGINX settings and settings in lib/support/ in general

When there is a list of steps to perform, usually that entails editing the configuration file and reconfiguring/restarting GitLab. In such case, follow the style below as a guide:

**For Omnibus installations**

1. Edit `/etc/gitlab/gitlab.rb`:

    ```ruby
    external_url "https://gitlab.example.com"
    ```

1. Save the file and [reconfigure] GitLab for the changes to take effect.

---

**For installations from source**

1. Edit `config/gitlab.yml`:

    ```yaml
    gitlab:
      host: "gitlab.example.com"
    ```

1. Save the file and [restart] GitLab for the changes to take effect.


[reconfigure]: path/to/administration/gitlab_restart.md#omnibus-gitlab-reconfigure
[restart]: path/to/administration/gitlab_restart.md#installations-from-source

In this case:

before each step list the installation method is declared in bold
three dashes (---) are used to create an horizontal line and separate the two methods
the code blocks are indented one or more spaces under the list item to render correctly
different highlighting languages are used for each config in the code block
the references guide is used for reconfigure/restart

API

Here is a list of must-have items. Use them in the exact order that appears on this document. Further explanation is given below.

Every method must be described using Grape's DSL (see https://gitlab.com/gitlab-org/gitlab-ce/blob/master/lib/api/environments.rb for a good example):
- desc for the method summary (you can pass it a block for additional details)
- params for the method params (this acts as description and validation of the params)
Every method must have the REST API request. For example:
```
GET /projects/:id/repository/branches
```
Every method must have a detailed description of the parameters.
Every method must have a cURL example.
Every method must have a response body (in JSON format).

Method description

Use the following table headers to describe the methods. Attributes should always be in code blocks using backticks (`).

| Attribute | Type | Required | Description |
| --------- | ---- | -------- | ----------- |

Rendered example:

Attribute	Type	Required	Description
`user`	string	yes	The GitLab username

cURL commands

Use https://gitlab.example.com/api/v3/ as an endpoint.
Wherever needed use this private token: 9koXpg98eAheJpvBs5tK.
Always put the request first. GET is the default so you don't have to include it.
Use double quotes to the URL when it includes additional parameters.
Prefer to use examples using the private token and don't pass data of username and password.

Methods	Description
`-H "PRIVATE-TOKEN: 9koXpg98eAheJpvBs5tK"`	Use this method as is, whenever authentication needed
`-X POST`	Use this method when creating new objects
`-X PUT`	Use this method when updating existing objects
`-X DELETE`	Use this method when removing existing objects

cURL Examples

Below is a set of cURL examples that you can use in the API documentation.

Simple cURL command

Get the details of a group:

curl --header "PRIVATE-TOKEN: 9koXpg98eAheJpvBs5tK" https://gitlab.example.com/api/v3/groups/gitlab-org

cURL example with parameters passed in the URL

Create a new project under the authenticated user's namespace:

curl --request POST --header "PRIVATE-TOKEN: 9koXpg98eAheJpvBs5tK" "https://gitlab.example.com/api/v3/projects?name=foo"

Post data using cURL's --data

Instead of using -X POST and appending the parameters to the URI, you can use cURL's --data option. The example below will create a new project foo under the authenticated user's namespace.

curl --data "name=foo" --header "PRIVATE-TOKEN: 9koXpg98eAheJpvBs5tK" "https://gitlab.example.com/api/v3/projects"

Post data using JSON content

Note: In this example we create a new group. Watch carefully the single and double quotes.

curl --request POST --header "PRIVATE-TOKEN: 9koXpg98eAheJpvBs5tK" --header "Content-Type: application/json" --data '{"path": "my-group", "name": "My group"}' https://gitlab.example.com/api/v3/groups

Post data using form-data

Instead of using JSON or urlencode you can use multipart/form-data which properly handles data encoding:

curl --request POST --header "PRIVATE-TOKEN: 9koXpg98eAheJpvBs5tK" --form "title=ssh-key" --form "key=ssh-rsa AAAAB3NzaC1yc2EA..." https://gitlab.example.com/api/v3/users/25/keys

The above example is run by and administrator and will add an SSH public key titled ssh-key to user's account which has an id of 25.

Escape special characters

Spaces or slashes (/) may sometimes result to errors, thus it is recommended to escape them when possible. In the example below we create a new issue which contains spaces in its title. Observe how spaces are escaped using the %20 ASCII code.

curl --request POST --header "PRIVATE-TOKEN: 9koXpg98eAheJpvBs5tK" "https://gitlab.example.com/api/v3/projects/42/issues?title=Hello%20Dude"

Use %2F for slashes (/).

Pass arrays to API calls

The GitLab API sometimes accepts arrays of strings or integers. For example, to restrict the sign-up e-mail domains of a GitLab instance to *.example.com and example.net, you would do something like this:

curl --request PUT --header "PRIVATE-TOKEN: 9koXpg98eAheJpvBs5tK" --data "domain_whitelist[]=*.example.com" --data "domain_whitelist[]=example.net" https://gitlab.example.com/api/v3/application/settings