Class: ToggleCraft::Evaluator

Inherits:
Object
  • Object
show all
Defined in:
lib/togglecraft/evaluator.rb

Overview

Flag evaluation engine for ToggleCraft Ruby SDK Evaluates boolean, multivariate, and percentage flags based on rules and context

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Evaluator 



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# File 'lib/togglecraft/evaluator.rb', line 9

def initialize
  @flags = Concurrent::Map.new
end

Instance Method Details

#current_percentage_for_flag(flag) ⇒ Integer

Calculate the current percentage for a flag based on rollout stages



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# File 'lib/togglecraft/evaluator.rb', line 137

def current_percentage_for_flag(flag)
  # If no rollout stages, use base percentage
  return flag[:percentage] if flag[:rollout_stages].nil? || flag[:rollout_stages].empty?

  now = Time.now
  active_stage = nil
  latest_start_time = nil

  # Find the most recent active stage
  flag[:rollout_stages].each do |stage|
    start_at = Time.parse(stage[:start_at])
    end_at = stage[:end_at] ? Time.parse(stage[:end_at]) : nil

    # Check if stage is currently active
    is_active = start_at <= now && (end_at.nil? || end_at > now)

    if is_active && (latest_start_time.nil? || start_at > latest_start_time)
      active_stage = stage
      latest_start_time = start_at
    end
  end

  # Return active stage percentage, or fall back to base percentage
  active_stage ? active_stage[:percentage] : flag[:percentage]
end

#evaluate(flag_key, context = {}, default_value = false) ⇒ Object

Evaluate any flag type



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# File 'lib/togglecraft/evaluator.rb', line 298

def evaluate(flag_key, context = {}, default_value = false)
  # Normalize key to symbol for lookup (flags are stored with symbol keys)
  flag = @flags[flag_key.to_sym]
  return default_value unless flag

  case flag[:type]
  when 'boolean'
    evaluate_boolean(flag_key, context, default_value)
  when 'multivariate'
    evaluate_multivariate(flag_key, context, default_value)
  when 'percentage'
    evaluate_percentage(flag_key, context, default_value)
  else
    warn "[ToggleCraft] Unknown flag type: #{flag[:type]}"
    default_value
  end
end

#evaluate_boolean(flag_key, context = {}, default_value = false) ⇒ Boolean

Evaluate a boolean flag



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# File 'lib/togglecraft/evaluator.rb', line 25

def evaluate_boolean(flag_key, context = {}, default_value = false)
  # Normalize key to symbol for lookup (flags are stored with symbol keys)
  flag = @flags[flag_key.to_sym]

  # Flag doesn't exist
  return default_value unless flag

  # Flag is not a boolean type
  unless flag[:type] == 'boolean'
    warn "[ToggleCraft] Flag #{flag_key} is not a boolean flag"
    return default_value
  end

  # Flag is disabled
  return false unless flag[:enabled]

  # Evaluate targeting rules
  if flag[:rules]&.any?
    flag[:rules].each do |rule|
      if evaluate_rule(rule, context)
        return rule[:value].nil? ? flag[:value] : rule[:value]
      end
    end
  end

  # Return default flag value
  flag[:value].nil? ? default_value : flag[:value]
end

#evaluate_condition(condition, context) ⇒ Boolean

Evaluate a single condition



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# File 'lib/togglecraft/evaluator.rb', line 217

def evaluate_condition(condition, context)
  attribute_value = Utils.get_nested_property(context, condition[:attribute])
  Utils.evaluate_operator(attribute_value, condition[:operator], condition[:values] || [])
end

#evaluate_multivariate(flag_key, context = {}, default_variant = nil) ⇒ String?

Evaluate a multivariate flag



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# File 'lib/togglecraft/evaluator.rb', line 59

def evaluate_multivariate(flag_key, context = {}, default_variant = nil)
  # Normalize key to symbol for lookup (flags are stored with symbol keys)
  flag = @flags[flag_key.to_sym]

  # Flag doesn't exist
  return default_variant unless flag

  # Flag is not a multivariate type
  unless flag[:type] == 'multivariate'
    warn "[ToggleCraft] Flag #{flag_key} is not a multivariate flag"
    return default_variant
  end

  # Flag is disabled
  return default_variant unless flag[:enabled]

  # Evaluate targeting rules
  if flag[:rules]&.any?
    flag[:rules].each do |rule|
      return rule[:variant] || flag[:default_variant] || default_variant if evaluate_rule(rule, context)
    end
  end

  # Use weighted distribution if weights are defined
  if flag[:weights]&.any?
    variant = select_variant_by_weight(flag_key, flag[:weights], context)
    return variant if variant
  end

  # Return default variant
  flag[:default_variant] || default_variant
end

#evaluate_percentage(flag_key, context = {}, default_value = false) ⇒ Boolean

Evaluate a percentage rollout flag



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# File 'lib/togglecraft/evaluator.rb', line 97

def evaluate_percentage(flag_key, context = {}, default_value = false)
  # Normalize key to symbol for lookup (flags are stored with symbol keys)
  flag = @flags[flag_key.to_sym]

  # Flag doesn't exist
  return default_value unless flag

  # Flag is not a percentage type
  unless flag[:type] == 'percentage'
    warn "[ToggleCraft] Flag #{flag_key} is not a percentage flag"
    return default_value
  end

  # Flag is disabled
  return false unless flag[:enabled]

  # Evaluate targeting rules first
  if flag[:rules]&.any?
    flag[:rules].each do |rule|
      return rule[:enabled].nil? || rule[:enabled] if evaluate_rule(rule, context)
    end
  end

  # Get current percentage (considering rollout stages)
  percentage = current_percentage_for_flag(flag)

  # Check percentage boundaries
  return false if percentage <= 0
  return true if percentage >= 100

  # Use consistent hashing based on user ID or random value
  user_id = context.dig(:user, :id) || context.dig(:user, :email) || SecureRandom.uuid
  hash_value = Utils.hash_key("#{flag_key}:#{user_id}")

  hash_value < percentage
end

#evaluate_rule(rule, context) ⇒ Boolean

Evaluate a single rule



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# File 'lib/togglecraft/evaluator.rb', line 179

def evaluate_rule(rule, context)
  return false if rule[:conditions].nil? || rule[:conditions].empty?

  result = nil
  previous_combinator = nil

  rule[:conditions].each do |condition|
    condition_result = evaluate_condition(condition, context)

    result = if result.nil?
               condition_result
    else
               # Apply combinator logic
               case previous_combinator
               when 'OR'
                 result || condition_result
               else
                 # Default to AND
                 result && condition_result
               end
    end

    previous_combinator = condition[:combinator] || 'AND'

    # Early exit for AND conditions
    return false if !result && previous_combinator == 'AND'

    # Early exit for OR conditions
    return true if result && previous_combinator == 'OR'
  end

  result || false
end

#flag_keys ⇒ Array<String>

Get all flag keys



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# File 'lib/togglecraft/evaluator.rb', line 265

def flag_keys
  @flags.keys
end

#flag_metadata(flag_key) ⇒ Hash?

Get flag metadata



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# File 'lib/togglecraft/evaluator.rb', line 272

def flag_metadata(flag_key)
  # Normalize key to symbol for lookup (flags are stored with symbol keys)
  flag = @flags[flag_key.to_sym]
  return nil unless flag

  metadata = {
    type: flag[:type],
    enabled: flag[:enabled]
  }

  case flag[:type]
  when 'multivariate'
    metadata[:variants] = flag[:variants]
    metadata[:default_variant] = flag[:default_variant]
  when 'percentage'
    metadata[:percentage] = flag[:percentage]
  end

  metadata
end

#has_flag?(flag_key) ⇒ Boolean

Check if a flag exists



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# File 'lib/togglecraft/evaluator.rb', line 258

def has_flag?(flag_key)
  # Normalize key to symbol for lookup (flags are stored with symbol keys)
  @flags.key?(flag_key.to_sym)
end

#percentage(flag_key) ⇒ Integer?

Get the current percentage value of a flag



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# File 'lib/togglecraft/evaluator.rb', line 166

def percentage(flag_key)
  # Normalize key to symbol for lookup (flags are stored with symbol keys)
  flag = @flags[flag_key.to_sym]

  return nil unless flag && flag[:type] == 'percentage'

  current_percentage_for_flag(flag)
end

#select_variant_by_weight(flag_key, weights, context) ⇒ String?

Select a variant based on weights using consistent hashing



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# File 'lib/togglecraft/evaluator.rb', line 227

def select_variant_by_weight(flag_key, weights, context)
  # Calculate total weight
  total_weight = 0
  variants = []

  weights.each do |variant, weight|
    total_weight += weight
    variants << { variant: variant.to_s, weight: weight }
  end

  return nil if total_weight.zero?

  # Use consistent hashing
  user_id = context.dig(:user, :id) || context.dig(:user, :email) || SecureRandom.uuid
  hash = Utils.hash_key("#{flag_key}:#{user_id}")
  scaled_hash = (hash.to_f / 100) * total_weight

  # Select variant based on hash
  accumulator = 0
  variants.each do |v|
    accumulator += v[:weight]
    return v[:variant] if scaled_hash < accumulator
  end

  # Fallback to last variant
  variants.last&.dig(:variant)
end

#update_flags(flags) ⇒ Object

Update the flags data



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# File 'lib/togglecraft/evaluator.rb', line 15

def update_flags(flags)
  @flags.clear
  flags&.each { |key, value| @flags[key] = value }
end