This repository contains the internal feature flag evaluation logic and data model used by the LaunchDarkly Go SDK. It is packaged separately because it is also used by internal LaunchDarkly components. Applications using the LaunchDarkly Go SDK should not need to reference this package directly.
This version of the project requires a Go version of 1.18 or higher.
By default, go-server-sdk-evaluation uses LaunchDarkly's open-source JSON library go-jsonstream to convert its data model types like FeatureFlag to and from JSON; this is considerably faster than Go's built-in encoding/json and does not depend on any third-party code. However, it can optionally integrate with the third-party library easyjson, which may be even faster in some cases, without requiring any changes in your code. To enable this, set the build tag launchdarkly_easyjson when you run go build, which both switches go-jsonstream to use easyjson internally and also generates MarshalEasyJSON/UnmarshalEasyJSON methods for each JSON-serializable type. The easyjson library is still under development and has some potential compatibility issues; see its documentation for more details.
If you do not set the launchdarkly_easyjson build tag, go-server-sdk-evaluation does not use any code from easyjson.
Check out our documentation for in-depth instructions on configuring and using LaunchDarkly. You can also head straight to the complete reference guide for the Go SDK, or the generated API documentation for this project.
We encourage pull requests and other contributions from the community. Check out our contributing guidelines for instructions on how to contribute to this SDK.
- LaunchDarkly is a continuous delivery platform that provides feature flags as a service and allows developers to iterate quickly and safely. We allow you to easily flag your features and manage them from the LaunchDarkly dashboard. With LaunchDarkly, you can:
- Roll out a new feature to a subset of your users (like a group of users who opt-in to a beta tester group), gathering feedback and bug reports from real-world use cases.
- Gradually roll out a feature to an increasing percentage of users, and track the effect that the feature has on key metrics (for instance, how likely is a user to complete a purchase if they have feature A versus feature B?).
- Turn off a feature that you realize is causing performance problems in production, without needing to re-deploy, or even restart the application with a changed configuration file.
- Grant access to certain features based on user attributes, like payment plan (eg: users on the ‘gold’ plan get access to more features than users in the ‘silver’ plan). Disable parts of your application to facilitate maintenance, without taking everything offline.
- LaunchDarkly provides feature flag SDKs for a wide variety of languages and technologies. Check out our documentation for a complete list.
- Explore LaunchDarkly
- launchdarkly.com for more information
- docs.launchdarkly.com for our documentation and SDK reference guides
- apidocs.launchdarkly.com for our API documentation
- blog.launchdarkly.com for the latest product updates