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diff --git a/doc/user/project/operations/feature_flags.md b/doc/user/project/operations/feature_flags.md index a9729204cd7..b0f7cfc966a 100644 --- a/doc/user/project/operations/feature_flags.md +++ b/doc/user/project/operations/feature_flags.md @@ -1,261 +1,5 @@ --- -stage: Release -group: Progressive Delivery -info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#designated-technical-writers +redirect_to: '../../../operations/feature_flags.md' --- -# Feature Flags **(PREMIUM)** - -> [Introduced](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/7433) in GitLab 11.4. - -With Feature Flags, you can deploy your application's new features to production in smaller batches. -You can toggle a feature on and off to subsets of users, helping you achieve Continuous Delivery. -Feature flags help reduce risk, allowing you to do controlled testing, and separate feature -delivery from customer launch. - -<i class="fa fa-youtube-play youtube" aria-hidden="true"></i> -For an example of feature flags in action, see [GitLab for Deploys, Feature Flags, and Error Tracking](https://www.youtube.com/embed/5tw2p6lwXxo). - -## How it works - -GitLab uses [Unleash](https://github.com/Unleash/unleash), a feature -toggle service. - -By enabling or disabling a flag in GitLab, your application -can determine which features to enable or disable. - -You can create feature flags in GitLab and use the API from your application -to get the list of feature flags and their statuses. The application must be configured to communicate -with GitLab, so it's up to developers to use a compatible client library and -[integrate the feature flags in your app](#integrate-feature-flags-with-your-application). - -## Create a feature flag - -To create and enable a feature flag: - -1. Navigate to your project's **Operations > Feature Flags**. -1. Click the **New feature flag** button. -1. Enter a name that starts with a letter and contains only lowercase letters, digits, underscores (`_`) - and dashes (`-`), and does not end with a dash (`-`) or underscore (`_`). -1. Enter a description (optional, 255 characters max). -1. Enter details about how the flag should be applied: - - In GitLab 13.0 and earlier: Enter an environment spec, - enable or disable the flag in this environment, and select a rollout strategy. - - In GitLab 13.1 and later (when [this feature flag](#feature-flag-behavior-change-in-130) is enabled): Select a strategy and then - the environments to apply the strategy to. -1. Click **Create feature flag**. - -The feature flag is displayed in the list. It is enabled by default. - -## Disable a feature flag for a specific environment - -In [GitLab 13.0 and earlier](https://gitlab.com/gitlab-org/gitlab/-/issues/8621), -to disable a feature flag for a specific environment: - -1. Navigate to your project's **Operations > Feature Flags**. -1. For the feature flag you want to disable, click the Pencil icon. -1. To disable the flag: - - In GitLab 13.0 and earlier: Slide the Status toggle for the environment. Or, to delete the - environment spec, on the right, click the **Remove (X)** icon. - - In GitLab 13.1 and later (when [this feature flag](#feature-flag-behavior-change-in-130) is - enabled): For each strategy it applies to, under **Environments**, delete the environment. -1. Click **Save changes**. - -## Disable a feature flag for all environments - -To disable a feature flag for all environments: - -1. Navigate to your project's **Operations > Feature Flags**. -1. For the feature flag you want to disable, slide the Status toggle to **Disabled**. - -The feature flag is displayed on the **Disabled** tab. - -## Feature flag behavior change in 13.0 - -> [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/35555) in GitLab 13.0. - -Starting in GitLab 13.0, you can apply a feature flag strategy across multiple environments, -without defining the strategy multiple times. - -This feature 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](../../../administration/feature_flags.md) -can enable it for your instance. - -To enable it: - -```ruby -Feature.enable(:feature_flags_new_version) -``` - -To disable it: - -```ruby -Feature.disable(:feature_flags_new_version) -``` - -## Feature flag strategies - -GitLab Feature Flag uses [Unleash](https://unleash.github.io) -as the feature flag engine. In Unleash, there is a concept of rulesets for granular feature flag controls, -called [strategies](https://unleash.github.io/docs/activation_strategy). -Supported strategies for GitLab Feature Flags are described below. - -### Rollout strategy - -> [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/8240) in GitLab 12.2. - -The selected rollout strategy affects which users will experience the feature as enabled. - -The status of an environment spec ultimately determines whether or not a feature is enabled at all. -For instance, a feature will always be disabled for every user if the matching environment spec has a disabled status, regardless of the chosen rollout strategy. -However, a feature will be enabled for 50% of logged-in users if the matching environment spec has an enabled status along with a **Percent rollout (logged in users)** strategy set to 50%. - -#### All users - -Enables the feature for all users. It is implemented using the Unleash -[`default`](https://unleash.github.io/docs/activation_strategy#default) -activation strategy. - -#### Percent rollout (logged in users) - -Enables the feature for a percentage of authenticated users. It is -implemented using the Unleash -[`gradualRolloutUserId`](https://unleash.github.io/docs/activation_strategy#gradualrolloutuserid) -activation strategy. - -Set a value of 15%, for example, to enable the feature for 15% of authenticated users. - -A rollout percentage may be between 0% and 100%. - -CAUTION: **Caution:** -If this strategy is selected, then the Unleash client **must** be given a user -ID for the feature to be enabled. See the [Ruby example](#ruby-application-example) below. - -#### User IDs - -> [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/8240) in GitLab 12.2. [Updated](https://gitlab.com/gitlab-org/gitlab/-/issues/34363) to be defined per environment in GitLab 12.6. - -A feature flag may be enabled for a list of target users. It is implemented -using the Unleash [`userWithId`](https://unleash.github.io/docs/activation_strategy#userwithid) -activation strategy. - -User IDs should be a comma-separated list of values. For example, `user@example.com, user2@example.com`, or `username1,username2,username3`, etc. - -CAUTION: **Caution:** -The Unleash client **must** be given a user ID for the feature to be enabled for -target users. See the [Ruby example](#ruby-application-example) below. - -## Integrate feature flags with your application - -To use feature flags with your application, get access credentials from GitLab. -Then prepare your application with a client library. - -### Get access credentials - -To get the access credentials that your application needs to communicate with GitLab: - -1. Navigate to your project's **Operations > Feature Flags**. -1. Click the **Configure** button to view the following: - - **API URL**: URL where the client (application) connects to get a list of feature flags. - - **Instance ID**: Unique token that authorizes the retrieval of the feature flags. - - **Application name**: The name of the running environment. For instance, - if the application runs for a production server, the application name would be - `production` or similar. This value is used for the environment spec evaluation. - -NOTE: **Note:** -The meaning of these fields might change over time. For example, we are not sure -if **Instance ID** will be single token or multiple tokens, assigned to the -**Environment**. Also, **Application name** could describe the version of -application instead of the running environment. - -### Choose a client library - -GitLab implements a single backend that is compatible with Unleash clients. - -With the Unleash client, developers can define, in the application code, the default values for flags. -Each feature flag evaluation can express the desired outcome if the flag isn't present in the -provided configuration file. - -Unleash currently [offers many SDKs for various languages and frameworks](https://github.com/Unleash/unleash#client-implementations). - -### Feature flags API information - -For API content, see: - -- [Feature Flags API](../../../api/feature_flags.md) -- [Feature Flag Specs API](../../../api/feature_flag_specs.md) (Deprecated and [scheduled for removal in GitLab 14.0](https://gitlab.com/gitlab-org/gitlab/-/issues/213369).) -- [Feature Flag User Lists API](../../../api/feature_flag_user_lists.md) -- [Legacy Feature Flags API](../../../api/feature_flags_legacy.md) - -### Golang application example - -Here's an example of how to integrate feature flags in a Golang application: - -```golang -package main - -import ( - "io" - "log" - "net/http" - - "github.com/Unleash/unleash-client-go" -) - -type metricsInterface struct { -} - -func init() { - unleash.Initialize( - unleash.WithUrl("https://gitlab.com/api/v4/feature_flags/unleash/42"), - unleash.WithInstanceId("29QmjsW6KngPR5JNPMWx"), - unleash.WithAppName("production"), - unleash.WithListener(&metricsInterface{}), - ) -} - -func helloServer(w http.ResponseWriter, req *http.Request) { - if unleash.IsEnabled("my_feature_name") { - io.WriteString(w, "Feature enabled\n") - } else { - io.WriteString(w, "hello, world!\n") - } -} - -func main() { - http.HandleFunc("/", helloServer) - log.Fatal(http.ListenAndServe(":8080", nil)) -} -``` - -### Ruby application example - -Here's an example of how to integrate feature flags in a Ruby application. - -The Unleash client is given a user ID for use with a **Percent rollout (logged in users)** rollout strategy or a list of **Target Users**. - -```ruby -#!/usr/bin/env ruby - -require 'unleash' -require 'unleash/context' - -unleash = Unleash::Client.new({ - url: 'http://gitlab.com/api/v4/feature_flags/unleash/42', - app_name: 'production', - instance_id: '29QmjsW6KngPR5JNPMWx' -}) - -unleash_context = Unleash::Context.new -# Replace "123" with the id of an authenticated user. -# Note that the context's user id must be a string: -# https://unleash.github.io/docs/unleash_context -unleash_context.user_id = "123" - -if unleash.is_enabled?("my_feature_name", unleash_context) - puts "Feature enabled" -else - puts "hello, world!" -end -``` +This document was moved to [another location](../../../operations/feature_flags.md). |