Confidence SDK for Android

This is the Android SDK for Confidence, a feature flagging and Experimentation system developed by Spotify.

The SDK allows you to consume feature flags and track events from your application.

Usage

Adding the package dependency

The latest release of the SDK is available on Maven central.

Add the following dependency to your gradle file to use it:

implementation("com.spotify.confidence:confidence-sdk-android:0.2.1")

Where 0.2.1 is the most recent version of this SDK.

Released versions can be found under "Releases" within this repository.

Creating the Confidence instance

You can create your Confidence instance using the ConfidenceFactory class like this:

val confidence = ConfidenceFactory.create(
    context = app.applicationContext,
    clientSecret = "<MY_SECRET>",
    region = ConfidenceRegion.EUROPE
)

Where MY_SECRET is an API key that can be generated in the Confidence UI

Setting the context

The context is a key-value map that will be used for sampling and for targeting input in assigning feature flag values by the Confidence backend. It is also a crucial way to create dimensions for metrics generated by event data.

The Confidence SDK supports multiple ways to set the Context. Some of them are mutating the current context of the Confidence instance, others are returning a new instance with the context changes applied.

confidence.putContext("key", ConfidenceValue.String("value")) // this will mutate the context of the current Confidence instance

val otherConfidenceInstance = confidence.withContext("key", ConfidenceValue.String("value")) // this will return a new Confidence instance with the context changes applied but the context of the original instance is kept intact

Fetching and resolving flags

Make the initial fetching of flags using the activateAndFetch method. This is a suspending function that will fetch the flags from the server and activate them. It needs to be run in a coroutine scope.

viewModelScope.launch {
    confidence.fetchAndActivate()
}

Once the flags are fetched and activated, you can access their value using the getValue method or the getFlag method. Both methods uses generics to return a type defined by the default value type.

The method getFlag returns an Evaluation object that contains the value of the flag, the reason for the value returned, and the variant selected.

In the case of an error, the default value will be returned and the Evaluation contains information about the error.

The method getValue will simply return the assigned value or the default.

val message: String = confidence.getValue("flag-name.message", "default message")
val messageFlag: Evaluation<String> = confidence.getFlag("flag-name.message", "default message")

val messageValue = messageFlag.value
// message and messageValue are the same

Tracking an event

Events are defined by a name and a message where the message is a key-value map of type <String, ConfidenceValue>. You can track an event using the track method.

All context data set on the Confidence instance will be appended to the event and its message.

confidence.track("button-tapped", mapOf("button_id" to ConfidenceValue.String("purchase_button")))

The Confidence SDK has support for EventProducer. This is a way to programmatically emit context changes and events into streams which can be consumed by the SDK to automatically emit events or to automatically update context data.

The Confidence SDK comes with a pre-defined event producer to emit some application lifecycle events: AndroidLifecycleEventProducer. To use it:

import com.spotify.confidence.AndroidLifecycleEventProducer
confidence.track(
    AndroidLifecycleEventProducer(
        application = getApplication(),
        trackActivities = false // or true
    )
)

OpenFeature Kotlin Confidence Provider

If you want to use OpenFeature, an OpenFeature Provider for the OpenFeature SDK is also available.

Adding the package dependency

The latest release of the Provider is available on Maven central.

Add the following dependency to your gradle file:

implementation("com.spotify.confidence:openfeature-provider-android:0.2.1")

Where 0.2.1 is the most recent version of the Provider. Released versions can be found under "Releases" within this repository.