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diff --git a/doc/development/feature_flags.md b/doc/development/feature_flags.md index 13f0c5cc33e..6bad91d6287 100644 --- a/doc/development/feature_flags.md +++ b/doc/development/feature_flags.md @@ -1,127 +1 @@ -# Manage feature flags - -Starting from GitLab 9.3 we support feature flags for features in GitLab via -[Flipper](https://github.com/jnunemaker/flipper/). You should use the `Feature` -class (defined in `lib/feature.rb`) in your code to get, set and list feature -flags. - -During runtime you can set the values for the gates via the -[features API](../api/features.md) (accessible to admins only). - -## Feature groups - -Starting from GitLab 9.4 we support feature groups via -[Flipper groups](https://github.com/jnunemaker/flipper/blob/v0.10.2/docs/Gates.md#2-group). - -Feature groups must be defined statically in `lib/feature.rb` (in the -`.register_feature_groups` method), but their implementation can obviously be -dynamic (querying the DB etc.). - -Once defined in `lib/feature.rb`, you will be able to activate a -feature for a given feature group via the [`feature_group` param of the features API](../api/features.md#set-or-create-a-feature) - -For GitLab.com, [team members have access to feature flags through Chatops](chatops_on_gitlabcom.md). Only -percentage gates are supported at this time. Setting a feature to be used 50% of -the time, you should execute `/chatops run feature set my_feature_flag 50`. - -## Feature flags for user applications - -This document only covers feature flags used in the development of GitLab -itself. Feature flags in deployed user applications can be found at -[Feature Flags](../user/project/operations/feature_flags.md) - -## Developing with feature flags - -In general, it's better to have a group- or user-based gate, and you should prefer -it over the use of percentage gates. This would make debugging easier, as you -filter for example logs and errors based on actors too. Furthermore, this allows -for enabling for the `gitlab-org` group first, while the rest of the users -aren't impacted. - -```ruby -# Good -Feature.enabled?(:feature_flag, project) - -# Avoid, if possible -Feature.enabled?(:feature_flag) -``` - -To use feature gates based on actors, the model needs to respond to -`flipper_id`. For example, to enable for the Foo model: - -```ruby -class Foo < ActiveRecord::Base - include FeatureGate -end -``` - -Features that are developed and are intended to be merged behind a feature flag -should not include a changelog entry. The entry should be added in the merge -request removing the feature flags. - -In the rare case that you need the feature flag to be on automatically, use -`default_enabled: true` when checking: - -```ruby -Feature.enabled?(:feature_flag, project, default_enabled: true) -``` - -For more information about rolling out changes using feature flags, refer to the -[Rolling out changes using feature flags](rolling_out_changes_using_feature_flags.md) -guide. - -### Frontend - -For frontend code you can use the method `push_frontend_feature_flag`, which is -available to all controllers that inherit from `ApplicationController`. Using -this method you can expose the state of a feature flag as follows: - -```ruby -before_action do - push_frontend_feature_flag(:vim_bindings) -end - -def index - # ... -end - -def edit - # ... -end -``` - -You can then check for the state of the feature flag in JavaScript as follows: - -```javascript -if ( gon.features.vimBindings ) { - // ... -} -``` - -The name of the feature flag in JavaScript will always be camelCased, meaning -that checking for `gon.features.vim_bindings` would not work. - -### Specs - -In the test environment `Feature.enabled?` is stubbed to always respond to `true`, -so we make sure behavior under feature flag doesn't go untested in some non-specific -contexts. - -Whenever a feature flag is present, make sure to test _both_ states of the -feature flag. - -See the -[testing guide](testing_guide/best_practices.md#feature-flags-in-tests) -for information and examples on how to stub feature flags in tests. - -## Enabling a feature flag (in development) - -In the rails console (`rails c`), enter the following command to enable your feature flag - -```ruby -Feature.enable(:feature_flag_name) -``` - -## Enabling a feature flag (in production) - -Check how to [roll out changes using feature flags](rolling_out_changes_using_feature_flags.md). +This document was moved to [another location](feature_flags/index.md). |