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LaunchDarkly Server-side SDK for Go

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LaunchDarkly overview

LaunchDarkly is a feature management platform that serves over 100 billion feature flags daily to help teams build better software, faster. Get started using LaunchDarkly today!

Supported Go versions

This version of the LaunchDarkly SDK has been tested with Go 1.14 and higher.

Getting started

Refer to the SDK documentation for instructions on getting started with using the SDK.

Note that the base import path is gopkg.in/launchdarkly/go-server-sdk.v5, not github.com/launchdarkly/go-server-sdk. This ensures that the package can be referenced not only as a Go module, but also by projects that use older tools like dep and govendor, because the 5.x release of the Go SDK supports either module or non-module usage. Future releases of this package, and of the Go SDK, may drop support for non-module usage.

HTTPS proxy

There are two ways to specify the use of a proxy server. First, you can do it programmatically: see ldcomponents.HTTPConfiguration().

Second, Go's standard HTTP library also provides built-in support for the use of an HTTPS proxy via the HTTPS_PROXY environment variable. If this environment variable is present, then the SDK will proxy all network requests through the URL provided.

How to set the HTTPS_PROXY environment variable on Mac/Linux systems:

export HTTPS_PROXY=https://web-proxy.domain.com:8080

How to set the HTTPS_PROXY environment variable on Windows systems:

set HTTPS_PROXY=https://web-proxy.domain.com:8080

If your proxy requires authentication then you can prefix the URN with your login information:

export HTTPS_PROXY=http://user:pass@web-proxy.domain.com:8080

or

set HTTPS_PROXY=http://user:pass@web-proxy.domain.com:8080

Database integrations

Feature flag data can be kept in a persistent store using a database integration; LaunchDarkly provides integrations for several databases, such as Redis, which are provided in separate packages. See the SDK reference guide for more information.

Integration with easyjson

The SDK frequently reads and writes JSON data when it communicates with LaunchDarkly services or uses a persistent data store. By default, it uses LaunchDarkly's open-source JSON library go-jsonstream, which is considerably faster than Go's built-in encoding/json and does not depend on any third-party code. However, the SDK 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. 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, the SDK does not use any code from easyjson.

Learn more

Check out our documentation for in-depth instructions on configuring and using LaunchDarkly. You can also head straight to the complete reference guide for this SDK or our code-generated API documentation.

Testing

We run integration tests for all our SDKs using a centralized test harness. This approach gives us the ability to test for consistency across SDKs, as well as test networking behavior in a long-running application. These tests cover each method in the SDK, and verify that event sending, flag evaluation, stream reconnection, and other aspects of the SDK all behave correctly.

Contributing

We encourage pull requests and other contributions from the community. Check out our contributing guidelines for instructions on how to contribute to this SDK.

About LaunchDarkly

  • 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