Module: Kilden::Hashing Private

Defined in:
lib/kilden/hashing.rb

Overview

This module is part of a private API. You should avoid using this module if possible, as it may be removed or be changed in the future.

The frozen rollout hashing (spec §8.3). v1 never evaluates flags locally — /decide does — but the algorithm is pinned now, tested against the platform-generated vectors, so local evaluation can arrive later without an API change or a bucketing flicker.

Constant Summary collapse

TWO_POW_64 =

This constant is part of a private API. You should avoid using this constant if possible, as it may be removed or be changed in the future. 

2.0**64

Class Method Summary collapse

Class Method Details

.bucket(flag_key, distinct_id) ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future. 



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# File 'lib/kilden/hashing.rb', line 16

def bucket(flag_key, distinct_id)
  fraction("#{flag_key}:#{distinct_id}") * 100
end

.fraction(input) ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future. 



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# File 'lib/kilden/hashing.rb', line 30

def fraction(input)
  Digest::SHA256.digest(input)[0, 8].unpack1("Q>") / TWO_POW_64
end

.variant_for(flag_key, distinct_id, variants) ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future. 



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# File 'lib/kilden/hashing.rb', line 20

def variant_for(flag_key, distinct_id, variants)
  point = fraction("#{flag_key}:#{distinct_id}:variant") * 100
  cumulative = 0.0
  variants.each do |variant|
    cumulative += variant.fetch("rollout_percentage")
    return variant.fetch("key") if point < cumulative
  end
  true
end