Implementing Feature Toggles
Feature Toggles are mechanisms in software development that allow teams to switch features or functionalities on and off without deploying new code. This technique enables dynamic control over the availability of features in production or other environments.
Goal
Feature toggles enable the adoption of best practice development and deployment strategies that remove the blockers that slow down the development process.
Context
With iterative product development we introduce a number of new challenges. We want to test new features with real users, but we also don't want all users to see beta features that are not yet ready. We want to be able to deploy frequently and rapidly but we don't want to impact the stability and reliability of the system. We want to have everyone working with the latest version of the code to reduce merge conflicts but we also want to be able to release when a feature is ready without having to wait for other features to be completed. Feature toggles are a way to address these challenges.
Use Cases
- Phased Rollouts: Gradually release a feature to subsets of users to monitor performance and gather feedback.
- A/B Testing: Compare the performance of two versions of a feature by enabling it for different groups of users.
- Risk Mitigation: Quickly disable a feature in case of issues, without deploying new code.
- Trunk Based Development: Hide unfinished features in the codebase, enabling continuous integration and deployment.
Inputs
| Artifact | Description |
|---|---|
| User Stories | Detailed descriptions of the functionality, performance criteria, and interfaces needed for each component. |
Outputs
| Artifact | Description | Benefits | ||||
|---|---|---|---|---|---|---|
Flags that are hardcoded into the application. | Useful for companies who want to use the release process to govern the activation and deactivation of features. | Toggles that can be controlled at runtime. | Useful for companies who want to gain the benefits of continuous deployment and rapid system recovery. |
Anti-patterns
- Overusing feature toggles: Adding too many toggles to the codebase, leading to code complexity and maintenance challenges.
- Leaving old toggles in the code: Toggles should be removed after the feature is stable to reduce technical debt and potential performance issues.
- Lack of governance around toggle use: Causing confusion and inconsistency in feature management.