gitlab-org--gitlab-foss/doc/development/documentation/feature_flags.md

118 lines
6.8 KiB
Markdown

---
info: For assistance with this Style Guide page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments-to-other-projects-and-subjects.
stage: none
group: unassigned
description: "GitLab development - how to document features deployed behind feature flags"
---
# Document features deployed behind feature flags
GitLab uses [feature flags](../feature_flags/index.md) to strategically roll
out the deployment of its own features. The way we document a feature behind a
feature flag depends on its state (enabled or disabled). When the state
changes, the developer who made the change **must update the documentation**
accordingly.
Every feature introduced to the codebase, even if it's behind a feature flag,
must be documented. For context, see the
[latest merge request that updated this guideline](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/47917#note_459984428).
When you document feature flags, you must:
- [Add version history text](#add-version-history-text).
- [Add a note at the start of the topic](#use-a-note-to-describe-the-state-of-the-feature-flag).
## Add version history text
When the state of a flag changes (for example, disabled by default to enabled by default), add the change to the version history.
Possible version history entries are:
```markdown
> - [Introduced](issue-link) in GitLab X.X [with a flag](../../administration/feature_flags.md) named `flag_name`. Disabled by default.
> - [Enabled on GitLab.com](issue-link) in GitLab X.X.
> - [Enabled on GitLab.com](issue-link) in GitLab X.X. Available to GitLab.com administrators only.
> - [Enabled on self-managed](issue-link) in GitLab X.X.
> - [Generally available](issue-link) in GitLab X.Y. [Feature flag `flag_name`](issue-link) removed.
```
You can combine entries if they happened in the same release:
```markdown
> - Introduced in GitLab 14.2 [with a flag](../../administration/feature_flags.md) named `ci_include_rules`. Disabled by default.
> - [Enabled on GitLab.com and self-managed](https://gitlab.com/gitlab-org/gitlab/-/issues/337507) in GitLab 14.3.
```
## Use a note to describe the state of the feature flag
Information about feature flags should be in a `FLAG` note at the start of the topic (just below the version history).
The note has three parts, and follows this structure:
```markdown
FLAG:
<Self-managed GitLab availability information.>
<GitLab.com availability information.>
<This feature is not ready for production use.>
```
### Self-managed GitLab availability information
| If the feature is... | Use this text |
|--------------------------|---------------|
| Available | ``On self-managed GitLab, by default this feature is available. To hide the feature, ask an administrator to [disable the feature flag](<path to>/administration/feature_flags.md) named `flag_name`.`` |
| Unavailable | ``On self-managed GitLab, by default this feature is not available. To make it available, ask an administrator to [enable the feature flag](<path to>/administration/feature_flags.md) named `flag_name`.`` |
| Available to some users | ``On self-managed GitLab, by default this feature is available to a subset of users. To show or hide the feature for all, ask an administrator to [change the status of the feature flag](<path to>/administration/feature_flags.md) named `flag_name`.`` |
| Available, per-group | ``On self-managed GitLab, by default this feature is available. To hide the feature per group, ask an administrator to [disable the feature flag](<path to>/administration/feature_flags.md) named `flag_name`.`` |
| Unavailable, per-group | ``On self-managed GitLab, by default this feature is not available. To make it available per group, ask an administrator to [enable the feature flag](<path to>/administration/feature_flags.md) named `flag_name`.`` |
| Available, per-project | ``On self-managed GitLab, by default this feature is available. To hide the feature per project or for your entire instance, ask an administrator to [disable the feature flag](<path to>/administration/feature_flags.md) named `flag_name`.`` |
| Unavailable, per-project | ``On self-managed GitLab, by default this feature is not available. To make it available per project or for your entire instance, ask an administrator to [enable the feature flag](<path to>/administration/feature_flags.md) named `flag_name`.`` |
| Available, per-user | ``On self-managed GitLab, by default this feature is available. To hide the feature per user, ask an administrator to [disable the feature flag](<path to>/administration/feature_flags.md) named `flag_name`.`` |
| Unavailable, per-user | ``On self-managed GitLab, by default this feature is not available. To make it available per user, ask an administrator to [enable the feature flag](<path to>/administration/feature_flags.md) named `flag_name`.`` |
### GitLab.com availability information
| If the feature is... | Use this text |
|---------------------------------------------|---------------|
| Available | `On GitLab.com, this feature is available.` |
| Available to GitLab.com administrators only | `On GitLab.com, this feature is available but can be configured by GitLab.com administrators only.`
| Unavailable | `On GitLab.com, this feature is not available.`|
### Optional information
If needed, you can add this sentence:
`The feature is not ready for production use.`
## Feature flag documentation examples
The following examples show the progression of a feature flag.
```markdown
> Introduced in GitLab 13.7 [with a flag](../../administration/feature_flags.md) named `forti_token_cloud`. Disabled by default.
FLAG:
On self-managed GitLab, by default this feature is not available. To make it available,
ask an administrator to [enable the feature flag](../administration/feature_flags.md) named `forti_token_cloud`.
The feature is not ready for production use.
```
When the feature is enabled in production, you can update the version history:
```markdown
> - Introduced in GitLab 13.7 [with a flag](../../administration/feature_flags.md) named `forti_token_cloud`. Disabled by default.
> - [Enabled on self-managed](https://gitlab.com/issue/etc) GitLab 13.8.
FLAG:
On self-managed GitLab, by default this feature is available. To hide the feature per user,
ask an administrator to [disable the feature flag](../administration/feature_flags.md) named `forti_token_cloud`.
```
And, when the feature is done and fully available to all users:
```markdown
> - Introduced in GitLab 13.7 [with a flag](../../administration/feature_flags.md) named `forti_token_cloud`. Disabled by default.
> - [Enabled on self-managed](https://gitlab.com/issue/etc) in GitLab 13.8.
> - [Enabled on GitLab.com](https://gitlab.com/issue/etc) in GitLab 13.9.
> - [Generally available](issue-link) in GitLab 14.0. [Feature flag `forti_token_cloud`](issue-link) removed.
```