Feature Flags or Feature Toggles enable organisations to rapidly deploy and release features to customers with a DevOps focus and separate feature releases from code releases. This presentation provides an intro to Feature Flagging, best practices and considerations to take note of when implementing.

1. Feature Flagging
Sam Fernando

2. SAM FERNANDO
 Digital Solutions Manager @ Oakton
 President of Adelaide Dynamics UG
 Technology Specialist
 Photography & Music
 linkedin.com/in/samfernandoau
 www.slideshare.net/shamiraf

3. Agenda
 What’s feature flagging/toggles?
 Feature flagging vs branching
 Type of flags
 Use cases
 Few libraries

4. What’s feature flagging
 aka Feature toggle, feature switcher, feature
flipper
 Dynamic control of program flow
 Dynamically enable/disable features at run time
 Gain more control of a release
 Increase continuous delivery
 Customer-first and DevOps focused
 Complimentary to branching practices

5. If (switch == true)
If (switch == false)

6. What are the benefits?
 Move forward quicker with releases
 Prevent blocking of a release
 Prevent merge conflicts
 Control feature behaviour multiple environments
 Less tedious code reviews
 Separate feature release from code release

7. Feature Flagging vs Branching
Dev Branch 1
Dev Branch 2
Master
Traditional

8. Feature Branching
Feature A
Feature B
Master Release

9. Types of Flags/Toggles
Release Toggles
Experiment Toggles
Ops Toggles
Permission Toggles

10. Use Cases
Early releases
Canary releases
Feature usage/monitoring
Kill switch
Maintenance Mode

11. Use Cases
Back end migrations
User targeting/beta invitations
Monitor less used features
Subscription management

12. .Net Libraries
 .Net Feature Flags
 Nfeature
 FeatureToggle
 FeatureSwitcher
 nToggle
 Toggler
 ….

13. Demo

14.  SaaS Solution
 Cloud based control panel
 Integrated with Azure DevOps & TFS
 Simple yet powerful
 Web hooks
 Integrations
 https://launchdarkly.com

15. Getting started with LaunchDarkly
 Install-Package LaunchDarkly.Client
 LdClient ldClient = new LdClient("YOUR_SDK_KEY");
User user = User.WithKey(username);
bool showFeature = ldClient.BoolVariation("your.feature.key", user,
false);
if (showFeature) {
// application code to show the feature
}
else {
// the code to run if the feature is off
}

16. Considerations
 Increased testing complexity
 Remove stale features
 Phase out feature flags when stable
 Decouple decision points
 Inversion of decision
 Avoid conditional branching
 Flag naming, Logging flag changes
 Control flag access

17. Further Reading
 https://martinfowler.com/bliki/FeatureToggle.html
 FeatureFlags.io

18. Questions?

19. Thank you!
linkedin.com/in/samfernandoau
www.slideshare.net/shamiraf