Module: Shipeasy::SDK::Eval

Defined in:
lib/shipeasy/sdk/eval.rb

Defined Under Namespace

Classes: Assignment, ExperimentResult

Class Method Summary collapse

Class Method Details

.enabled?(v) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/shipeasy/sdk/eval.rb', line 10

def self.enabled?(v)
  v == 1 || v == true
end

.eval_experiment(exp, flags_blob, exps_blob, user, exp_name: nil, sticky_store: nil) ⇒ Object

exp_name + sticky_store are optional so existing callers stay deterministic. When a sticky_store is passed, an enrolled unit whose stored salt prefix still matches skips the allocation gate (so a shrinking allocation keeps it in) and returns the stored group without re-running the pick. A fresh pick is persisted via store.set; a salt mismatch / missing stored group falls through to re-bucket + overwrite. Mirrors the TS reference (doc 20 §2). exp_name is the key under which the entry is stored.

Pooling / holdout-gate / reserved-headroom / universe param-default merge (doc 20 §B) are layered in here so both the low-level parity path and the universe assign() path share ONE classify. The added steps are all guarded by presence checks, so a legacy blob (no hashVersion/pool/reserved) behaves exactly as before.



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# File 'lib/shipeasy/sdk/eval.rb', line 128

def self.eval_experiment(exp, flags_blob, exps_blob, user, exp_name: nil, sticky_store: nil)
  universe_name  = exp && exp["universe"]
  universe       = exps_blob&.dig("universes", universe_name)
  param_defaults = param_defaults_from_schema(universe && (universe["param_schema"] || universe[:param_schema]))

  not_in = ExperimentResult.new(in_experiment: false, group: "control", params: nil)
  as_group = lambda do |g|
    ExperimentResult.new(
      in_experiment: true, group: g["name"], params: merge_params(param_defaults, g["params"]),
    )
  end

  return not_in unless exp && exp["status"] == "running"

  targeting_gate = exp["targetingGate"]
  if targeting_gate && !targeting_gate.empty?
    gate = flags_blob&.dig("gates", targeting_gate)
    return not_in unless gate && eval_gate(gate, user)
  end

  bucket_by = exp["bucketBy"] || exp[:bucketBy]
  uid = pick_identifier(user, bucket_by)
  return not_in unless uid

  # One segment in the universe's shared [0, 10000) hash space. The holdout
  # carve-out AND every experiment's pool slice are disjoint ranges of THIS
  # segment — that's what makes "held out / taken / free" a real partition.
  universe_seg = murmur3("#{universe_name}:#{uid}") % 10000

  holdout = universe&.dig("holdout_range")
  if holdout
    return not_in if universe_seg >= holdout[0] && universe_seg <= holdout[1]
  end

  # Holdout gate: a passing gate holds the unit out of every experiment in
  # the universe (mirrors the universe carve-out, but gate-driven).
  holdout_gate = exp["holdoutGate"]
  if holdout_gate && !holdout_gate.to_s.empty?
    gate = flags_blob&.dig("gates", holdout_gate)
    return not_in if gate && eval_gate(gate, user)
  end

  salt          = exp["salt"]
  allocation_pct = exp["allocationPct"] || 0
  groups = exp["groups"] || []
  salt8 = (salt || "")[0, 8]

  # Sticky short-circuit: an enrolled unit whose stored salt prefix still
  # matches skips allocation and returns the stored group. If the stored
  # group no longer exists, fall through to re-bucket + overwrite.
  if sticky_store && exp_name
    entry = (sticky_store.get(uid) || {})[exp_name]
    if entry && entry["s"] == salt8
      g = groups.find { |x| x["name"] == entry["g"] }
      return as_group.call(g) if g
    end
  end

  # Allocation. Pooled (hashVersion >= 2 with a slice) gives real mutual
  # exclusion: the unit's universe segment must fall in the claimed range.
  # Legacy falls back to an independent per-experiment salt so siblings
  # overlap freely (the existing parity path).
  hash_version = exp["hashVersion"] || exp[:hashVersion] || 1
  pool_offset  = exp["poolOffsetBp"] || exp[:poolOffsetBp]
  pool_size    = exp["poolSizeBp"] || exp[:poolSizeBp]
  pooled       = hash_version >= 2 && !pool_offset.nil? && !pool_size.nil? && pool_size > 0
  if pooled
    lo = pool_offset
    hi = pool_offset + pool_size
    return not_in if universe_seg < lo || universe_seg >= hi
  else
    return not_in if murmur3("#{salt}:alloc:#{uid}") % 10000 >= allocation_pct
  end

  # Group split over [0, usable) where usable = 10000 - reserved; a unit in
  # the reserved tail is left unassigned so an appended variant can absorb it.
  reserved = (exp["reservedHeadroomBp"] || exp[:reservedHeadroomBp] || 0)
  reserved = 0 if reserved < 0
  reserved = 10000 if reserved > 10000
  usable = 10000 - reserved
  group_hash = murmur3("#{salt}:group:#{uid}") % 10000
  return not_in if group_hash >= usable

  cumulative = 0
  groups.each_with_index do |g, i|
    cumulative += g["weight"]
    if group_hash < cumulative || i == groups.length - 1
      sticky_store.set(uid, exp_name, { "g" => g["name"], "s" => salt8 }) if sticky_store && exp_name
      return as_group.call(g)
    end
  end

  not_in
end

.eval_gate(gate, user) ⇒ Object 



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# File 'lib/shipeasy/sdk/eval.rb', line 73

def self.eval_gate(gate, user)
  return false if enabled?(gate["killswitch"])
  return false unless enabled?(gate["enabled"])

  (gate["rules"] || []).each do |rule|
    return false unless match_rule(rule, user)
  end

  uid = user["user_id"] || user[:user_id] || user["anonymous_id"] || user[:anonymous_id]
  # No unit id (an unidentified request before any anon id is minted): a
  # fully-rolled gate is on for everyone, so it can be answered without
  # bucketing; a fractional rollout genuinely needs a stable unit, so deny
  # until one exists. Rules above are still checked, so targeting wins.
  # See experiment-platform/18-identity-bucketing.md.
  return (gate["rolloutPct"] || gate[:rolloutPct] || 0) >= 10000 unless uid

  salt = gate["salt"] || gate[:salt]
  murmur3("#{salt}:#{uid}") % 10000 < (gate["rolloutPct"] || gate[:rolloutPct] || 0)
end

.match_rule(rule, user) ⇒ Object 



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# File 'lib/shipeasy/sdk/eval.rb', line 23

def self.match_rule(rule, user)
  attr  = rule["attr"] || rule[:attr]
  op    = rule["op"]   || rule[:op]
  value = rule["value"] || rule[:value]
  actual = user[attr] || user[attr.to_sym]

  case op
  when "eq"       then actual == value
  when "neq"      then actual != value
  when "in"       then Array(value).include?(actual)
  when "not_in"   then !Array(value).include?(actual)
  when "contains"
    if actual.is_a?(String) && value.is_a?(String)
      actual.include?(value)
    elsif actual.is_a?(Array)
      actual.include?(value)
    else
      false
    end
  when "regex"
    actual.is_a?(String) && value.is_a?(String) &&
      Regexp.new(value).match?(actual) rescue false
  when "gt", "gte", "lt", "lte"
    a = to_num(actual)
    b = to_num(value)
    return false if a.nil? || b.nil?
    case op
    when "gt"  then a > b
    when "gte" then a >= b
    when "lt"  then a < b
    when "lte" then a <= b
    end
  else
    false
  end
end

.merge_params(param_defaults, group_params) ⇒ Object

universeDefaults ⊕ variantOverride — a variant inherits every universe default it doesn't explicitly override. A nil defaults map short-circuits to the variant params (dup'd) alone.



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# File 'lib/shipeasy/sdk/eval.rb', line 110

def self.merge_params(param_defaults, group_params)
  gp = group_params || {}
  param_defaults ? param_defaults.merge(gp) : gp.dup
end

.murmur3(key) ⇒ Object 



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# File 'lib/shipeasy/sdk/eval.rb', line 6

def self.murmur3(key)
  Murmur3.hash32(key, 0)
end

.param_defaults_from_schema(schema) ⇒ Object

Flatten a universe param schema ([{ "name", "type", "default" }, ...]) to a plain name => default map — the defaults assign() layers under a variant's override map. Returns nil for a null/empty schema so the merge short-circuits. Mirrors the TS reference / @shipeasy/core.



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# File 'lib/shipeasy/sdk/eval.rb', line 99

def self.param_defaults_from_schema(schema)
  return nil if schema.nil? || schema.empty?
  schema.each_with_object({}) do |p, h|
    name = p["name"] || p[:name]
    h[name] = p.key?("default") ? p["default"] : p[:default]
  end
end

.pick_identifier(user, bucket_by) ⇒ Object

Pick the bucketing identifier. When bucket_by is set and the user carries that attribute as a non-empty string (or any number, stringified), bucket on it — so a whole company/org lands on one variant. Otherwise fall back to user_id, then anonymous_id. Mirrors core's pickIdentifier.



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# File 'lib/shipeasy/sdk/eval.rb', line 64

def self.pick_identifier(user, bucket_by)
  if bucket_by && !bucket_by.to_s.empty?
    v = user[bucket_by] || user[bucket_by.to_sym]
    return v if v.is_a?(String) && !v.empty?
    return v.to_s if v.is_a?(Numeric)
  end
  user["user_id"] || user[:user_id] || user["anonymous_id"] || user[:anonymous_id]
end

.to_num(v) ⇒ Object 



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# File 'lib/shipeasy/sdk/eval.rb', line 14

def self.to_num(v)
  case v
  when Numeric then v.finite? ? v : nil
  when String
    n = Float(v) rescue nil
    n&.finite? ? n : nil
  end
end