debian-mirror-gitlab/doc/development/documentation/feature_flags.md

---
type: reference, dev
stage: none
group: Development
info: "See the Technical Writers assigned to Development Guidelines: https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments-to-development-guidelines"
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.

## Criteria

According to the process of [deploying GitLab features behind feature flags](../feature_flags/process.md):

> - _By default, feature flags should be off._
> - _Feature flags should remain in the codebase for a short period as possible to reduce the need for feature flag accounting._
> - _In order to build a final release and present the feature for self-managed users, the feature flag should be at least defaulted to on._

See how to document them below, according to the state of the flag:

- [Features disabled by default](#features-disabled-by-default).
- [Features that became enabled by default](#features-that-became-enabled-by-default).
- [Features directly enabled by default](#features-directly-enabled-by-default).
- [Features that can be enabled or disabled for a single project](#features-enabled-by-project).
- [Features with the feature flag removed](#features-with-flag-removed).

The [`**(CORE ONLY)**`](styleguide/index.md#product-tier-badges) badge or equivalent for
the feature's tier should be added to the line and heading that refers to
enabling/disabling feature flags as Admin access is required to do so,
therefore, it indicates that it cannot be done by regular users of GitLab.com.

### Features disabled by default

For features disabled by default, add or improve the docs with every change in line with the
[definition of done](../contributing/merge_request_workflow.md#definition-of-done).

Include details of the feature flag in the documentation:

- Say that it's disabled by default.
- Say whether it's enabled on GitLab.com.
- If the feature can be enabled/disabled for a single project, add the
  [by-project information](#features-enabled-by-project). Otherwise,
  do not say anything about it.
- Say whether it's recommended for production use.
- Document how to enable and disable it.
- Add a warning to the user saying that the feature might be disabled.

For example, for a feature disabled by default, disabled on GitLab.com, cannot
be enabled for a single project, and is not ready for production use:

````markdown
# Feature Name

> - [Introduced](link-to-issue) in GitLab 12.0.
> - It's [deployed behind a feature flag](<replace with path to>/user/feature_flags.md), disabled by default.
> - It's disabled on GitLab.com.
> - It's not recommended for production use.
> - To use it in GitLab self-managed instances, ask a GitLab administrator to [enable it](#anchor-to-section). **(CORE ONLY)**

WARNING:
This feature might not be available to you. Check the **version history** note above for details.

(...Regular content goes here...)

<!-- Add this at the end of the file -->

### Enable or disable <Feature Name> **(CORE ONLY)**

<Feature Name> is under development and not ready for production use. It is
deployed behind a feature flag that is **disabled by default**.
[GitLab administrators with access to the GitLab Rails console](<replace with path to>/administration/feature_flags.md)
can enable it.

To enable it:

```ruby
Feature.enable(:<feature flag>)
```

To disable it:

```ruby
Feature.disable(:<feature flag>)
```
````

Adjust the blurb according to the state of the feature you're documenting.
Replace `<Feature name>`, `**(CORE ONLY)**`, `<feature flag>`, and
`<replace with path to>`, and `#anchor-to-section` accordingly.

### Features that became enabled by default

For features that were released disabled by default but became enabled by
default:

- Say that it became enabled by default.
- Say whether it's enabled on GitLab.com.
- If the feature can be enabled/disabled for a single project, add the
  [by-project information](#features-enabled-by-project). Otherwise,
  do not say anything about it.
- Say whether it's recommended for production use.
- Document how to disable and enable it.
- Add a warning to the user saying that the feature might be disabled.

For example, for a feature initially deployed disabled by default, that became
enabled by default, that is enabled on GitLab.com, and is ready for production
use:

````markdown
# Feature Name

> - [Introduced](link-to-issue) in GitLab 12.0.
> - It was [deployed behind a feature flag](<replace with path to>/user/feature_flags.md), disabled by default.
> - [Became enabled by default](link-to-issue) on GitLab 12.1.
> - It's enabled on GitLab.com.
> - It's recommended for production use.
> - For GitLab self-managed instances, GitLab administrators can opt to [disable it](#anchor-to-section). **(CORE ONLY)**

WARNING:
This feature might not be available to you. Check the **version history** note above for details.

(...Regular content goes here...)

<!-- Add this at the end of the file -->

### Enable or disable <Feature Name> **(CORE ONLY)**

<Feature Name> is under development but ready for production use.
It is deployed behind a feature flag that is **enabled by default**.
[GitLab administrators with access to the GitLab Rails console](<replace with path to>/administration/feature_flags.md)
can opt to disable it.

To enable it:

```ruby
Feature.enable(:<feature flag>)
```

To disable it:

```ruby
Feature.disable(:<feature flag>)
```
````

Adjust the blurb according to the state of the feature you're documenting.
Replace `<Feature name>`, `**(CORE ONLY)**`, `<feature flag>`,
`<replace with path to>`, and `#anchor-to-section` accordingly.

### Features directly enabled by default

For features enabled by default:

- Say it's enabled by default.
- Say whether it's enabled on GitLab.com.
- If the feature can be enabled/disabled for a single project, add the
  [by-project information](#features-enabled-by-project). Otherwise,
  do not say anything about it.
- Say whether it's recommended for production use.
- Document how to disable and enable it.
- Add a warning to the user saying that the feature might be disabled.

For example, for a feature enabled by default, enabled on GitLab.com, that
cannot be enabled for a single project, and is ready for production use:

````markdown
# Feature Name

> - [Introduced](link-to-issue) in GitLab 12.0.
> - It's [deployed behind a feature flag](<replace with path to>/user/feature_flags.md), enabled by default.
> - It's enabled on GitLab.com.
> - It's recommended for production use.
> - For GitLab self-managed instances, GitLab administrators can opt to [disable it](#anchor-to-section). **(CORE ONLY)**

WARNING:
This feature might not be available to you. Check the **version history** note above for details.

(...Regular content goes here...)

<!-- Add this at the end of the file -->

### Enable or disable <Feature Name> **(CORE ONLY)**

<Feature Name> is under development but ready for production use.
It is deployed behind a feature flag that is **enabled by default**.
[GitLab administrators with access to the GitLab Rails console](<replace with path to>/administration/feature_flags.md)
can opt to disable it.

To enable it:

```ruby
Feature.enable(:<feature flag>)
```

To disable it:

```ruby
Feature.disable(:<feature flag>)
```
````

Adjust the blurb according to the state of the feature you're documenting.
Replace `<Feature name>`, `**(CORE ONLY)**`, `<feature flag>`,
`<replace with path to>`, and `#anchor-to-section` accordingly.

### Features enabled by project

If the feature can be enabled/disabled for a single project, include in the
version history note:

```markdown
> - It can be enabled or disabled for a single project.
```

Then add the by-project code to the code blocks:

Enable code:

```ruby
# For the instance
Feature.enable(:<feature flag>)
# For a single project
Feature.enable(:<feature flag>, Project.find(<project id>))
```

Disable code:

```ruby
# For the instance
Feature.disable(:<feature flag>)
# For a single project
Feature.disable(:<feature flag>, Project.find(<project id>))
```

For example, for a feature enabled by default, enabled on GitLab.com, that can
be enabled by project, and is ready for production use:

````markdown
# Feature Name

> - [Introduced](link-to-issue) in GitLab 12.0.
> - It's [deployed behind a feature flag](<replace with path to>/user/feature_flags.md), enabled by default.
> - It's enabled on GitLab.com.
> - It can be enabled or disabled for a single project.
> - It's recommended for production use.
> - For GitLab self-managed instances, GitLab administrators can opt to [disable it](#anchor-to-section). **(CORE ONLY)**

WARNING:
This feature might not be available to you. Check the **version history** note above for details.

(...Regular content goes here...)

<!-- Add this at the end of the file -->

### Enable or disable <Feature Name> **(CORE ONLY)**

<Feature Name> is under development but ready for production use.
It is deployed behind a feature flag that is **enabled by default**.
[GitLab administrators with access to the GitLab Rails console](<replace with path to>/administration/feature_flags.md)
can opt to disable it.

To enabled it:

```ruby
# For the instance
Feature.enable(:<feature flag>)
# For a single project
Feature.enable(:<feature flag>, Project.find(<project id>))
```

To disable it:

```ruby
# For the instance
Feature.disable(:<feature flag>)
# For a single project
Feature.disable(:<feature flag>, Project.find(<project id>))
```
````

Adjust the blurb according to the state of the feature you're documenting.
Replace `<Feature name>`, `**(CORE ONLY)**`, `<feature flag>`,
`<replace with path to>`, and `#anchor-to-section` accordingly.

### Features with flag removed

Once the feature is ready and the flag has been removed, clean up the
documentation. Remove the feature flag mention keeping only a note that
mentions the flag in the version history notes:

````markdown
# Feature Name

> - [Introduced](link-to-issue) in GitLab 12.0.
> - [Feature flag removed](link-to-issue) in GitLab 12.2.

(...Regular content...)

````