Feature flags with LaunchDarkly
For what feature flags are and how they pair with trunk-based development, see the HMCTS-wide feature flags practice. This page covers LaunchDarkly, the feature flag service for services on the Cloud Native Platform.
Accessing LaunchDarkly
Developers automatically get access by being part of ‘DTS CFT Developers’ or ‘DTS SDS Developers’, non-developers can get access with the ‘DTS LaunchDarkly’ group. See Microsoft Entra ID to request access. You will need to login from myapps.microsoft.com.
After you’ve logged in once you will be able to login from app.launchdarkly.com.
Documentation
Documentation can be accessed directly from the LaunchDarkly website. Their blog contains good information.
Creating a new project
See hmcts/launchdarkly-terraform for instructions on how to setup your new project.
Environments
We currently provide ‘Test’ and ‘Production’ environments by default within Launch Darkly. Flags are generally set to the same value in both ‘Production’ and the ‘Test’ environment, flag targeting is used to control rollout of flags to users across environments.
If your team does require additional environments, you can do this by updating your teams terraform.tfvars. It is not recommended to do this as targeting rules should be simpler to manage and ensure consistency across environments.