Feature Toggling Strategies

Attendees: @robpark, Johnny S, Andy, Jason, Lex

• How do you deal with conditionals
  • Implement at the interface level
  • If you see conditionals littered throughout your code, you're likely missing a layer of abstraction

• Why toggle?
  • To be able turn a feature on/off

• Strategies
  • per user
  • algorithmically - needs to be consistent for a given user though

• clean up?
  • what if the user can turn it on?
  • installed software vs webapp

• testing

• metrics

• use feature flags; they're good
• don't have too many
  • is that 80? 5?
• use if not all of your users can be exposed to the feature
• they may not be binary; they could be enumerations
• a good measure may be "if you sales people can call it out, then it's big enough to need a toggle"

• feature flags may follow the same rules as using many branches effectively
• although if you should avoid getting to the point of needing to manage dependencies across feature flags

• are you now version-less? no semver?
  • or versioning is at least decoupled from deployment
  • "for this release we'll just turn on these 10 flags"
  • the "current version" is the current "default" set of flags

• what shouldn't be behind a feature flag?
  • bug fixes