Feature Flagging

Mobile app product owners need the flexibility to roll out new features in their app without having to invest in multiple app releases. They may also want to roll out features gradually to a percentage of the user base, to test effectiveness. Adobe Target can be used to experiment with UX features like color, copy, buttons, text & images and provide those features to specific audiences.

In this lesson, we’ll create a “feature flag” offer which can be used as a trigger to enable specific app features.

Learning Objectives

At the end of this lesson, you will be able to:

Add a New Location to the Prefetch Request to the Home Activity

In the demo app from our previous lessons, we’ll add a new location called “wetravel_feature_flag_recs” to the prefetch request in the Home Activity and load it to the screen with a new Java method.

First, verify that the wetravel_feature_flag_recs constant is added in the Constant.java file:

Here is the code:

public static final String wetravel_feature_flag_recs = "wetravel_feature_flag_recs";

Now add the location to the prefetch request and load a new function called processFeatureFlags():

Here is the full updated code:

public void targetPrefetchContent() {
    List<TargetPrefetchObject> prefetchList = new ArrayList<>();

    Map<String, Object> params1;
    params1 = new HashMap<String, Object>();
    params1.put("at_property", "7962ac68-17db-1579-408f-9556feccb477");

    prefetchList.add(Target.createTargetPrefetchObject(Constant.wetravel_engage_home, params1));
    prefetchList.add(Target.createTargetPrefetchObject(Constant.wetravel_engage_search, params1));
    prefetchList.add(Target.createTargetPrefetchObject(Constant.wetravel_feature_flag_recs, params1));

    Target.TargetCallback<Boolean> prefetchStatusCallback = new Target.TargetCallback<Boolean>() {
        @Override
        public void call(final Boolean status) {
            HomeActivity.this.runOnUiThread(new Runnable() {
                @Override
                public void run() {
                    String cachingStatus = status ? "YES" : "NO";
                    System.out.println("Received Response from prefetch : " + cachingStatus);
                    engageMessage();
                    processFeatureFlags();
                    setUp();

                }
            });
        }};
    Target.prefetchContent(prefetchList, null, prefetchStatusCallback);
}

public void processFeatureFlags() {
    Target.loadRequest(Constant.wetravel_feature_flag_recs, "", null, null, null,
            new Target.TargetCallback<String>(){
                @Override
                public void call(final String s) {
                    runOnUiThread(new Runnable() {
                        @Override
                        public void run() {
                            System.out.println("Feature Flags : " + s);
                            if(s != null && !s.isEmpty()) {
                                //enable or disable features
                            }
                        }
                    });
                }
            });
}

Validate the Feature Flag Request

Once the code is added, run the Emulator on the Home Activity and watch Logcat for the updated response:

Create a Feature Flag JSON Offer

We’ll now create a simple JSON offer that will act as a flag or trigger for a specific audience - the audience that would receive the feature roll-out in their app. In the Target interface, create a new offer:

Let’s name it “Feature Flag v1” with the value

Create an Activity

Now let’s create an A/B Test activity with that offer. For detailed steps on creating an activity see the previous lesson. The activity will only need one audience for this example. In a live scenario, you may want to build out specific custom audiences for specific feature roll-outs, then set the activity to use those audiences. In this example, we’ll just allocate traffic 50/50 (50% to visitors who would see the feature updates, and 50% to visitors who would see a standard experience). Here is the configuration for the activity:

Activate the activity.

Validate the Feature Flag Activity

Now use the emulator to watch for the request. Since we set the targeting to 50% of users, there’s a 50% you’ll see the feature flag response contain the {enable:1} value.

If you don’t see the {enable:1} value, that means you weren’t targeted for the experience. As a temporary test, to force the offer to show, you could:

In a live scenario, the {enable:1} response can be used to enable more custom logic in your app to display the specific feature set you want to show your target audience.

Conclusion

Nice work! You now have the skills needed to roll-out features to specific user audiences.