Example

Featureflags Launchdarkly

Demonstrates how to evaluate LaunchDarkly feature flags through the Helix feature-flag client. Shows FeatureClient, FeatureContext, and the Helix properties used to point the LaunchDarkly starter at a real LaunchDarkly environment.

Group: REST API
Path: examples/rest-api/featureflags-launchdarkly

Source README

Overview

Helix Spring Boot web service that shows how to evaluate feature flags with the Helix LaunchDarkly starter.

Run this example from the shared examples build:


./gradlew -p examples runExample -Pexample=rest-api/featureflags-launchdarkly --init-script "$(pwd)/helix.init.gradle"

What It Shows

adding helix-featureflags-launchdarkly-spring-boot-starter to a Helix REST API
evaluating LaunchDarkly flags through the Helix FeatureClient
building a FeatureContext with user and plan attributes for targeting
configuring the LaunchDarkly SDK key through Helix application properties
relying on the starter to create the LaunchDarkly client and Helix feature client wiring

Endpoints

GET /v1/featureflags-launchdarkly/experience/{userId}
GET /liveness
GET /health

Example success response

{
  "userId": "pilot-user",
  "plan": "standard",
  "betaCheckoutEnabled": true,
  "prioritySupportEnabled": false,
  "message": "Serve the beta checkout flow.",
  "evaluationMode": "launchdarkly-sdk"
}

Development

Building the Application

Run the following command to build the service:


./gradlew clean build

Testing the Application

Run the following command to run the service tests:


./gradlew test
./gradlew integration

Trying the API

Run the service with a LaunchDarkly SDK key:

Then try:

This example assumes you have corresponding LaunchDarkly flags defined in your environment, such as:

beta-checkout - priority-support

The tests for this example override the launchdarkly-feature-client bean so the application code can be verified without depending on a live LaunchDarkly environment.


./gradlew bootRun --args='--helix.featureflags.launchdarkly.sdkkey=YOUR_SDK_KEY'


curl "http://localhost:8080/v1/featureflags-launchdarkly/experience/pilot-user?plan=standard"

curl "http://localhost:8080/v1/featureflags-launchdarkly/experience/standard-user?plan=enterprise"

curl "http://localhost:8080/v1/featureflags-launchdarkly/experience/standard-user?plan=standard"