Feature flags, also known as the feature toggles, are important concepts in the field of DevOps. They have been around for a long time and have been used continually by developers for their convenience. As software development services providers are striving for higher agility, practices such as feature flagging are becoming increasingly relevant. If you are not familiar with the concept of a feature flag, let’s start with understanding what feature flagging is.
What is Feature Flagging?
Feature flags are used for the process of branching your code, which means to turn certain code paths on and off to separate the release of new features from the actual deployment of our code. Why do DevOps developers want to branch their code through feature flags? Well, feature flagging is a great software development practice for two reasons. Firstly, for features that are a work-in-progress, developers can use a feature flag to hold their release until they are ready. This ensures the release of other features that are ready is not delayed just because one feature is not. Secondly, features that are being worked on can be kept off using the feature flag and only once it is ready it can be turned on. This allows developers to work directly on the feature without changing the main code, also known as the trunk or master branch. When all is working and ready to be released, turning on the feature toggle releases the feature, just like a switch.
To understand feature flags in the simplest term, feature flags are “if/else” statements to develop a conditional branch or pathway into your code. For example, you can use a feature flag to state that “if so and so feature is enabled, run new algorithm; or else, run old algorithm.” This allows developers to control the functionality—if the feature flag is enabled only then the new algorithm is executed; else skipped. This is the most basic form of feature flags, however, they could be more complex.
Feature flags are a practical way for software teams to maintain the delivery and release of features, and there are many advantages of using them. However, too many feature flags can make your code more complex and difficult to manage.
Here are the best practices of feature flagging that can save your project from becoming a feature flag hell.
More Feature Flags Equals Complex Code
Feature flagging is a good practice that can help you maintain the delivery and release of different features, however, using too many feature flags can quickly turn your code into a feature flag hell. The more feature flags you create, the more code paths are going to be created, this increases the complexity of your code and makes the testing process harder. A higher number of code paths can cause a mess and risk the functionality of your code. Therefore, it is best to only create feature flags when it makes sense and always check if a previously created feature flag can be re-used instead.
Name Your Feature Flags
For efficient management of feature flags, it is crucial to have a proper flag naming system. Without it, it is possible to confuse the flags, forget why they were created for, or create flags with the same name—all of which can cause disruptions and confusion. When working with a team of developers, it is important to ensure that everyone follows the same labeling method so they can get the information about the flag just by looking at the name. Otherwise, it is likely that a team member might mistakenly trigger the flags, upsetting your code.
Log and Clean Up Old Flags
Over time, it can become difficult to keep track of the changes that are made to a feature flag. Therefore, it is important to track changes through logging, especially when working in teams. Using logging, you can keep a track of who created the feature flag, who made a change and at what time. This can save you from wasting time figuring out who was responsible for what change. A log will set the record straight about every change introduced for every feature flag.
This is also great to know which flag and code paths are obsolete and redundant now. When you know which flags are unused you can clean them from your code to avoid any conflict or confusion.
Use a Feature Flag Management Tool
For better management, control and visibility of your feature flags, you can use available feature flag management tools. Like every other management tool, feature flag management tools are enterprise-scale software to manage feature flags. Some of the most popular tools include LaunchDarkly, Rollout and Bullet Train. Tools like these can make the management of feature flags easier for you and increase your development speed.
Use Feature Flags to Collect Data
When it comes to scaling your product, feature flags can be of great help to collect data from users. For instance, if you want to introduce a new feature, you can roll out the change slowly to a few users first. Using feature flags, you can make the new feature or update available to a smaller set of users only and collect data about how well they respond to the release. You can then use their feedback to improve or change your features to deliver an improved user experience. Feature flags are used in this manner by companies such as Facebook and Netflix to test their new features before releasing them for the entire user base.
