SRE Thailand Bootcamp

Week 12: Feature Flags & Release Management

Theme: Feature flags with LaunchDarkly/Unleash, release trains, semantic versioning.

Learning Objectives

1. Implement feature flags in Go using Unleash (open-source)
2. Manage release trains and semantic versioning
3. Use feature flags for gradual rollout and kill switches
4. Separate deploy from release

Reading Materials

• Unleash Documentation
• Unleash Go SDK
• LaunchDarkly Feature Flag Fundamentals
• Feature Toggles (Martin Fowler)
• Semantic Versioning
• Release Management Best Practices (Google)

Finger Exercises (choose 2)

1. Deploy Unleash server to kind. Create a feature flag called "new-checkout-flow" with 50% rollout.
2. In the Go app, use the Unleash Go SDK to check "new-checkout-flow". Route to new or old handler.
3. Create a kill switch flag: if toggled off, the app returns a maintenance page.

Project

Integrate Unleash into the Go app:

• Flag: new-authentication-flow (gradual rollout to 25%, 50%, 100%)
• Flag: enable-order-cancellation (kill switch)
• Flag: promotion-engine-v2 (internal beta users only by user ID)

Build a release pipeline:

• Release train: every Friday, cut a release branch from main
• Release candidate: deploy to staging via ArgoCD, run integration tests
• Production rollout: auto-promote through Argo Rollouts
• Rollback: revert the feature flag, not the code

Document the release process in RELEASE.md

Time Budget