Feature flags

Introduced in GitLab 11.4.

Feature flags are toggles that allow you to enable or disable specific features. These flags are typically used:

  • For beta features that are made available for volunteers to test, but that are not ready to be enabled for all users.

    Beta features are sometimes incomplete or need further testing. A user who wants to use a beta feature can choose to accept the risk and explicitly enable the feature with a feature flag. Other users who do not need the feature or who are not willing to accept the risk on their system have the feature disabled by default and are not impacted by possible bugs and regressions.

  • For breaking changes that result in functionality deprecation or feature removal in the near future.

    As the product evolves, features are sometimes changed or removed entirely. Known bugs are often fixed, but in some cases, users have already found a workaround for a bug that affected them; forcing users to adopt the standardized bug fix might cause other problems with their customized configurations.

    In such cases, the feature flag is used to switch from the old behavior to the new one on demand. This allows users to adopt new versions of the product while giving them time to plan for a smooth, permanent transition from the old behavior to the new behavior.

Feature flags are toggled using environment variables. To:

  • Activate a feature flag, set the corresponding environment variable to "true" or 1.
  • Deactivate a feature flag, set the corresponding environment variable to "false" or 0.

Available feature flags

Feature flag Default value Deprecated To be removed with Description
FF_CMD_DISABLE_DELAYED_ERROR_LEVEL_EXPANSION false ✗   Disables EnableDelayedExpansion for error checking for when using Window Batch shell
FF_NETWORK_PER_BUILD false ✗   Enables creation of a Docker network per build with the docker executor
FF_USE_LEGACY_KUBERNETES_EXECUTION_STRATEGY true ✗   When set to false disables execution of remote Kubernetes commands through exec in favor of attach to solve problems like #4119
FF_USE_DIRECT_DOWNLOAD true ✗   When set to true Runner tries to direct-download all artifacts instead of proxying through GitLab on a first try. Enabling might result in a download failures due to problem validating TLS certificate of Object Storage if it is enabled by GitLab
FF_SKIP_NOOP_BUILD_STAGES true ✗   When set to false all build stages are executed even if running them has no effect
FF_SHELL_EXECUTOR_USE_LEGACY_PROCESS_KILL false ✓ 14.0 Use the old process termination that was used prior to GitLab 13.1 where only SIGKILL was sent
FF_RESET_HELPER_IMAGE_ENTRYPOINT true ✓ 14.0 Enables adding an ENTRYPOINT layer for Helper images imported from local Docker archives by the docker executor, in order to enable importing of user certificate roots

Enable feature flag in pipeline configuration

You can use CI variables to enable feature flags:

  • For all jobs in the pipeline (globally): 

    variables:
  FEATURE_FLAG_NAME: 1

  • For a single job: 

    job:
  stage: test
  variables:
    FEATURE_FLAG_NAME: 1
  script:
  - echo "Hello"

Enable feature flag for Runner

To enable the feature for every job a Runner runs, specify the feature flag as an environment variable in the Runner configuration: 

[[runners]]
  name = "ruby-2.6-docker"
  url = "https://CI/"
  token = "TOKEN"
  limit = 0
  executor = "docker"
  builds_dir = ""
  shell = ""
  environment = ["FEATURE_FLAG_NAME=1"]