Haskell SDK reference

Overview

This topic documents how to get started with the Haskell SDK, and links to reference information on all of the supported features.

Get started

Follow the steps below to get started using the LaunchDarkly SDK in your Haskell application.

Install the SDK

The root module of the SDK LaunchDarkly.Server re-exports the entire project.

Here is an example:

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import LaunchDarkly.Server

Initialize the client

After you import and install the SDK, create a single shared instance of Client. Specify your SDK key to authorize your application to connect to a particular environment within LaunchDarkly.

Here’s how:

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client :: IO Client
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client = makeClient $ makeConfig "YOUR_SDK_KEY"

To learn more about the specific configuration properties that are available in this SDK, read Config.

Evaluate a context

You can use client to check which variation a particular context will receive for a given feature flag. To learn more, read Evaluating flags and Flag evaluation reasons. For more information about how contexts are specified, read Context configuration.

Here’s how:

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boolVariation client "example-flag-key" (makeContext "example-context-key" "context-kind") False

Shut down the client

Shut down the client when your application terminates. To learn more, read Shutting down.

Supported features

This SDK supports the following features:

• Anonymous contexts and users
• Configuration, including
  • Application metadata configuration
  • Service endpoint configuration
• Context configuration
• Evaluating flags
• Flag evaluation reasons
• Flushing events
• Getting all flags
• Identifying and changing contexts
• Offline mode
• Private attributes
• Reading flags from a file
• Relay Proxy configuration
  • Using proxy mode
  • Using daemon mode
• Secure mode
• Sending custom events
• Shutting down
• Storing data
• Test data sources