Ship Faster With Feature Flags

You've been working long and hard on this feature and your humongous PR is up, your code review takes days and the QA process spots one or two bugs you have to fix. You finally fix the issues and are ready to deploy to PlayStore, but that may be another 1 or 2 days (depending) and the app is out. Over a week has gone by trying to ship this feature, but what if we could cut down that time and ship faster with more confidence? Enter feature flags. I will share my learnings about feature flags from previous projects, how they quicken the development process, how you could start making use of them and some things to watch out for when using them.

Transcript

1. Ship Faster with feature flags 🚀🚩 #droidconKE2022
2. Who is this guy? - Software Engineer @Flink - Android GDE - Twitter Noisemaker @_davidodari - My family's’ IT guy
3. Scenarios 📽 “One of my most productive days was throwing away 1,000 lines of code.” by Ken Thompson.
4. “This New Law affects us we need to change things before we get fined.”
5. Possible solutions - Force update all users 🥶
6. Enter feature flags
7. What are they? 🤔
8. “Software technique that enables you to make changes to code during runtime without additional code changes”
9. Are we magicians now?🪄
10. How do we get them in(Basic) 1. Have a simple json file. 2. Load up the json file configurations. 3. React to changes made in json file.
11. STEP 1: Have A Simple Json file
12. STEP 1: Have A Simple Json file:HOSTING
13. STEP 2: Load up the json config val features = FeatureFlagsService.createFeaturesService().getFeatures() for (feature in features.record.flags){ if(feature.key == "red_button_color" && feature. enabled){ val dummyBtn = findViewById<Button>(R.id. dummyBtn) dummyBtn.setBackgroundColor(Color. RED) } }
14. STEP 3: React to changes to the json
15. That’s it right?😎
16. PROS CONS - Fast Setup - Good for basic use cases - Think about hosting json - Easy to introduce breaking changes - No connection to analytics - Handle cache logic - Has no form of documentation
17. Inhouse or 3rd party #droidconKE22
18. INHOUSE 🏠
19. PROS CONS - Custom setup built for the business needs - Can configure audiences(depends) - Could have some form of documentation - More maintenance work
20. 3RD PARTY 🤝
21. Some Examples
22. Some Examples
23. Some Examples
24. Some Examples
25. How do we get them in 1. Follow integration guide 2. Use SDK as per stated in the API guide
26. STEP 1: follow integration guide(FIREBASE)
27. STEP 1: follow integration guide
28. STEP 2: USE SDK val remoteConfig: FirebaseRemoteConfig = Firebase.remoteConfig val configSettings = remoteConfigSettings { minimumFetchIntervalInSeconds = 3600 } remoteConfig.setConfigSettingsAsync(configSettings)
29. STEP 2: USE SDK remoteConfig.fetchAndActivate() .addOnCompleteListener(this) { task -> if (task.isSuccessful) { val updated = task.result Log.d(TAG, "Config params updated: $updated") Toast.makeText(this, "Fetch and activate succeeded", Toast.LENGTH_SHORT).show() } else { Toast.makeText(this, "Fetch failed", Toast.LENGTH_SHORT).show() } displayWelcomeMessage() }
30. STEP 2: USE SDK Use available methods on remote config object • getBoolean() • getDouble() • getLong() • getString()
31. PROS CONS - Can configure audiences - Maintained by other teams and you can focus on business logic - Has edge cases you haven’t thought of yet and might be useful - Can be connected to analytics tools and build on A/B testing - Has documentation that is maintained - Caching strategies in place - Not fully custom to your needs or could be abit restrictive - Might be pricy
32. General Benefits - Review PRs with more confidence - Reduce need for force updates
33. General gotchas - Requires a restart of the app to propagate changes. - Testing paths will have to cater for both scenarios. - Keeping track of feature flags and cleanup.At what point do you qualify the flag. - Can be a bit unclear whether or not to include features behind flags in your release notes, especially if everyone isn’t getting it.
34. Interesting use cases
35. Interesting use cases - Large refactoring tasks not just product related tasks - Depending on tooling support, can stand in for backend.* - Client didn’t pay 😉
36. Feature Flags vs A/B TESTING VS PRODUCT FLAVORS
37. References - Json Bin: Json Hosting - Firebase: Remote Config - Launch Darkly - Optimizely - Remote config codelab
38. QnA
39. Thanks for coming