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Persistent Assignment

Persistent assignment allows you to ensure that a user's variant stays consistent while an experiment is running, regardless of changes to allocation or targeting.

Persistent Storage Adapter​

The persistent storage adapter allows you to plug in your own storage solution that Statsig SDK uses to persist user assignments. The storage interface consists of just a load and save API for read/write operations.

info

Currently only supported in Go and Ruby

Persistent Storage Logic​

  • Providing a storage adapter on Statsig initialization will give the SDK access to read & write on your custom storage
  • Providing user persisted values to get_experiment will inform the SDK to
    • save the evaluation of the current user on first evaluation
    • load the previously saved evaluation of a persisted user on subsequent evaluations

Example usage​

Statsig.initialize(
  'secret-key',
  StatsigOptions.new(
    user_persistent_storage: DummyPersistentStorageAdapter.new
  )
)
persisted_user = StatsigUser.new({ 'userID' => 'test-123' })
exp = Statsig.get_experiment( # User gets saved to persisted storage
  persisted_user,
  'active_experiment',
  Statsig::GetExperimentOptions.new(
    user_persisted_values: Statsig.get_user_persisted_values(persisted_user, 'userID')
  )
)
puts exp.group_name # 'Control'
exp = Statsig.get_experiment( # User evaluates using values from persisted storage
  StatsigUser.new({'userID' => 'unknown'}),
  'active_experiment',
  Statsig::GetExperimentOptions.new(
    user_persisted_values: Statsig.get_user_persisted_values(persisted_user, 'userID')
  )
)
puts exp.group_name # 'Control'