Feature Flags or Feature Toggle is a technique in software development that attempts to provide an alternative to maintaining multiple branches in source code (known as feature branches), such that a software feature can be tested even before it is completed and ready for release. For example, developers can test a particular feature during run time and disable it for other users.
Feature flag is a lynchpin for our progressive delivery strategy; it allows many small incremental versions of software to be simultaneously delivered without the cost of constant branching and merging.
Our ultimate goal is to provide an easy way to configure and monitor feature flags that integrate into the continuous development cycle. Visual ties from feature flags to ongoing issues and merge requests will help understand the state and exposure of each feature and a comprehensive dashboard will allow developers to take action when necessary in order to minimize risk and technical debt.
The GitLab Feature Flag is built with an Unleash-compatible API, ensuring interoperability with any other compatible tooling, and taking advantage of the various client libraries available for Unleash. Unleash have recently announced that they are spinning up a hosted (paid) option while maintaining their open source offering. We will be monitoring this closely.
While Feature flags are a great tool for incremental delivery, they can introduce technical debt when applied improperly. For example, feature flags can be forgotten and left as stale code.
In order to make it easier to duplicate and extend upon existing Feature Flag user lists, we will add the ability to copy users from one Feature Flag user list to another via gitlab#215491.
This category is currently at the "Viable" maturity level, and our next maturity target is Complete (see our definitions of maturity levels).
Our focus at the moment is on using the feature internally to deliver GitLab itself. This will be driving new requirements to the base features that are out there already, and also helping us to ensure the list for
complete maturity is accurate. Our plan is for our feature flag solution to compete with other products on the market, such as LaunchDarkly or Rollout. As we work towards
complete maturity, we expect that our primary adopters of this feature will be pre-existing GitLab users looking for incremental value. For buyers who are considering replacing other tools, and looking for something that integrates feature flags with issues, we will also provide a valuable solution as we head towards
Key deliverables to achieve this are:
Other feature flag products offer more comprehensive targeting and configuration. The simplicity of our solution is actually a strength compared to this in some cases, but there is some basic functionality still to add.
A competitor review of LaunchDarkly can be found in gitlab&4102. If you have additional insights or are interested in joining in the conversation, please comment on the issue.
Analysts are recognizing that this sort of capability is becoming more a part of what's fundamentally needed for a continuous delivery platform, in order to minimize blast radius from changes. Often, solutions in this space are complex and hard to get up and running with, and they are not typically bundled or well integrated with CD solutions.
This backs up our desire to not over complicated the solution space here, and highlights the need for guidance. gitlab#9450 introduces new in-product documentation to help development and operations teams learn how to successfully adopt feature flags.
Our top customer success issue, and one that comes up frequently in customer calls is gitlab#8239 which talks about feature flag permissions. This will explicitly give permissions to toggle feature flags on/off based on the environment.
Our top customer issue is gitlab#206666 which captures changes in feature flag strategy in an audit log. This will help in terms of compliance and in investigating historical feature flag changes.
Adding a webhook for feature flag events via gitlab#220898 to trigger pipeline actions and even email/slack notifications in case a flag was toggled. This can be really useful for automation, and to help keep you informed on the feature flag status at all times.
We have completed the re-architecture of Feature Flags, adding the ability to support multiple strategies per environment via API and UI (gitlab#204895. Our Fulfillment, Expansion, and Product Analytics teams have joined the dogfooding effort for this. The feedback from this process is being tracked in gitlab&3760.
One of our main themes in CI/CD is Progressive delivery. Feature flags, by definition, are a form of progressive delivery as they allow you to deploy code incrementally and control the audience that will receive the new code. Our top vision issues are connecting Feature Flags to issues, Merge Requests, and Epics so that our users can benefit from our single application toolchain. This will enable users to better understand the context of a feature flag and their state to the associated plan, release, and deployment.