How do you manage feature toggles across multiple environments?

1 Why use feature toggles?

Feature toggles can provide many benefits for continuous delivery, such as faster feedback loops, reduced risk, incremental development, A/B testing, and dark launching. With feature toggles, you can release features to a subset of users or environments and collect data before rolling them out to everyone. If a feature causes errors or performance issues, you can toggle it off without having to roll back the entire deployment. Additionally, you can work on large or complex features in small chunks and hide them behind a toggle until they are ready. Feature toggles also allow you to compare the impact of different versions of a feature on user behavior and satisfaction and test the scalability and reliability of a feature in production without exposing it to users.

2 How to implement feature toggles?

There are various ways to implement feature toggles, depending on your needs and preferences. Configuration files, databases, environment variables, code, and services are all common methods. Configuration files are simple and flexible, but require access to the file system. Databases allow for dynamic changes and centralized control, but add a dependency and latency to the application. Environment variables are easy and portable, but may not be secure or scalable for large numbers of toggles. Hard-coding the toggle values in source code is fast and reliable, but requires code changes and deployments to modify the toggles. Services such as LaunchDarkly, Unleash, or FeatureFlow offer advanced features like user segmentation and analytics, but may come with additional costs and complexity.

3 How to organize feature toggles?

Organizing your feature toggles in a clear and consistent way is essential to avoid confusion and chaos. Name your toggles descriptively, such as 'enable-new-checkout' or 'disable-email-notifications', and group them into categories like feature, release, experiment, or operational. Additionally, document your toggles in comments, README files, or wikis, including their purpose, status, and dependencies. Moreover, use a naming convention or a prefix to distinguish between different types of toggles (e.g., 'dev-', 'test-', 'prod-', or 'exp-'), and a hierarchy or scope to define the scope of your toggles (e.g., global, environment, user, or session).

4 How to synchronize feature toggles?

One of the challenges of using feature toggles across multiple environments is maintaining synchronization and alignment. Different toggle values in different environments can lead to unexpected behaviors or errors. To avoid this, you can use a single source of truth for your toggle values, such as a configuration file or database, and share it across all environments. Additionally, a version control system or configuration management tool can be used to track and deploy toggle values. Feature toggle dashboards and monitoring tools can also be used to visualize and compare toggle values across environments. Finally, feature toggle APIs or webhooks can be used to notify and update toggle values across different environments.

5 How to clean up feature toggles?

When using feature toggles across multiple environments, it is essential to clean up and remove them when they are no longer needed. If you neglect to do so, you may end up with technical debt, complexity, and security risks. To clean up your feature toggles, you should set a time limit or expiration date for them and set a reminder or alert to remove them when they expire. You can also assign a status or state for your toggles and mark them as active, inactive, or deprecated depending on their lifecycle stage. Additionally, it is recommended that you use a review or audit process for your toggles and check them regularly for usage, performance, and impact. Finally, you should use a refactoring or migration strategy for your toggles and replace them with permanent code or configuration changes when they are stable and validated.

6 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?