diff options
Diffstat (limited to 'src/content/en/slide/2020/10/19/feature-flags.adoc')
| -rw-r--r-- | src/content/en/slide/2020/10/19/feature-flags.adoc | 234 |
1 files changed, 6 insertions, 228 deletions
diff --git a/src/content/en/slide/2020/10/19/feature-flags.adoc b/src/content/en/slide/2020/10/19/feature-flags.adoc index 553cf4c..360c00f 100644 --- a/src/content/en/slide/2020/10/19/feature-flags.adoc +++ b/src/content/en/slide/2020/10/19/feature-flags.adoc @@ -1,230 +1,8 @@ ---- -# Rollout, feature flag, experiment, operational toggle += Rollout, feature flag, experiment, operational toggle +:categories: presentation +:deck: feature-flags.pdf -@Different use cases for backend, frontend and mobile +Different use cases for backend, frontend and mobile, and why the +four things people call "feature flags" are not the same thing. ---- -. -. -. -# "Feature flags" tend to come up when talking about continuous deployment - ---- -. -. -. -. -@CI: continuous integration -. -@CD: continuous delivery -. -@CD: continuous deployment - ---- -## Types -. -. -. -1. rollout -2. feature flag -3. experiment -4. operational toggle - -% {favicon.svg} ---- -## Rollout - -# For *rolling out* a new version of software - -Short-lived using percentages - -% FIXME: links -- a new deployment of kubernetes -- new APK released to the Play Store - ---- -## Feature flag - -# For turning a feature *on* or *off* - -Medium-lived using allow list, A/B test, percentage, app version, etc. - -- :new-chargeback-flow -- :new-debit-card-activation-screen - ---- -## Experiment - -# For analysing behaviour - -Medium-lived using allow list and A/B test - -- :debit-withdrawal-test - ---- -## Operational toggle - -# For disabling features in #crash-like situations - -Long-lived using percentage - -- :bank-barcode-payment -- :savings-bank-barcode-query-provider - ---- -. -. -@We know know about the types -# But they have different relevance for backend, frontend and mobile - ---- -## backend -. -. -1. rollout: k8s blue/green, canary and ~common-rollout~ common-xp -2. feature flag: ~common-rollout~ common-xp and datasets -3. experiment: common-xp -4. operational toggle: ~common-rollout~ common-xp - ---- -## frontend -. -. -1. rollout: CDN and page refreshes -2. feature flag: percentages and maybe IPs (no :customer/id on the website) -3. experiment: via dynamic backend control -4. operational toggle: via dynamic backend control - ---- -## backend -. -. -1. rollout: app stores -2. feature flag: via dynamic backend control -3. experiment: via dynamic backend control -4. operational toggle: via dynamic backend control - ---- -. -. -@Key differentiator is -# how much *control* we have over the environment - ---- -## backend -# full control -% FIXME: emoji -% 🎉 - ---- -## frontend -# partial control -We choose when to make a new version available - ---- -## mobile -# very limited control -- app stores can restrict updates (worse for iOS) -- customers still have to download new versions - ---- -# Costs -- more complex code -- compatibility with old app versions -- nesting is exponential - ---- -# Benefits -- dynamicity - ---- -## weighting costs × benefits -# The less control we have, the more we value dynamicity - ---- -## weighting costs × benefits -. -. -. -- backend: sometimes worth the cost -- frontend: almost always worth the cost -- mobile: *always* worth the cost - ---- -. -. -. -# Best practices - ---- -# dynamic content > feature flag -Always true for mobile, almost always for frontend - ---- -# Use :include-list for named groups -Always true for backend, frontend and mobile - - {:rules - #{{:types :include-list - :content {:filename "debit-team-members.txt"}}}} - ---- -# Always use :app-version -Only for mobile - - {:rules - #{{:types :app-version - :content {:min-version #{{:platform :android - :code 1000000} - {:platform :ios - :code 2000000}}}}}} - ---- -# Extend ~common-rollout~ common-xp if required - -That's how :include-list, :app-version, etc. were born - ---- -# Beware of many nested feature flags -True for backend, frontend and mobile - ---- -# Don't delete app-facing feature flags -True for mobile - ---- -. -. -. -# Include a feature flag on the whiteboarding phase - ---- -. -. -. -# Include deleting/retiring the feature flag at the end - ---- -# Avoid renaming a feature flag -Use :app-version with :min-version instead - ---- -. -. -. -# And most importantly... - ---- -# *Always* rely on a feature flag on the app -Never do a hotfix, avoid expedited releases at all costs - ---- -## References -. -% FIXME: links -1. "Feature Toggles (aka Feature Flags)", by Pete Hodgson -2. "Continuous integration vs. delivery vs. deployment", by Sten Pittet -3. Accelerate, by N. Forsgren, J. Humble and G. Kim -4. these slides: euandre.org/slide/ -5. prose version of this presentation -6. view source +link:{deck}[Read the deck (PDF)]. |