1 files changed, 95 insertions, 0 deletions
diff --git a/app/validators/feature_flag_strategies_validator.rb b/app/validators/feature_flag_strategies_validator.rb
new file mode 100644
index 00000000000..e542d52c50a
--- /dev/null
+++ b/app/validators/feature_flag_strategies_validator.rb
@@ -0,0 +1,95 @@
+# frozen_string_literal: true
+
+class FeatureFlagStrategiesValidator < ActiveModel::EachValidator
+  STRATEGY_DEFAULT = 'default'.freeze
+  STRATEGY_GRADUALROLLOUTUSERID = 'gradualRolloutUserId'.freeze
+  STRATEGY_USERWITHID = 'userWithId'.freeze
+  # Order key names alphabetically
+  STRATEGIES = {
+    STRATEGY_DEFAULT => [].freeze,
+    STRATEGY_GRADUALROLLOUTUSERID => %w[groupId percentage].freeze,
+    STRATEGY_USERWITHID => ['userIds'].freeze
+  }.freeze
+  USERID_MAX_LENGTH = 256
+
+  def validate_each(record, attribute, value)
+    return unless value
+
+    if value.is_a?(Array) && value.all? { |s| s.is_a?(Hash) }
+      value.each do |strategy|
+        strategy_validations(record, attribute, strategy)
+      end
+    else
+      error(record, attribute, 'must be an array of strategy hashes')
+    end
+  end
+
+  private
+
+  def strategy_validations(record, attribute, strategy)
+    validate_name(record, attribute, strategy) &&
+    validate_parameters_type(record, attribute, strategy) &&
+    validate_parameters_keys(record, attribute, strategy) &&
+    validate_parameters_values(record, attribute, strategy)
+  end
+
+  def validate_name(record, attribute, strategy)
+    STRATEGIES.key?(strategy['name']) || error(record, attribute, 'strategy name is invalid')
+  end
+
+  def validate_parameters_type(record, attribute, strategy)
+    strategy['parameters'].is_a?(Hash) || error(record, attribute, 'parameters are invalid')
+  end
+
+  def validate_parameters_keys(record, attribute, strategy)
+    name, parameters = strategy.values_at('name', 'parameters')
+    actual_keys = parameters.keys.sort
+    expected_keys = STRATEGIES[name]
+    expected_keys == actual_keys || error(record, attribute, 'parameters are invalid')
+  end
+
+  def validate_parameters_values(record, attribute, strategy)
+    case strategy['name']
+    when STRATEGY_GRADUALROLLOUTUSERID
+      gradual_rollout_user_id_parameters_validation(record, attribute, strategy)
+    when STRATEGY_USERWITHID
+      user_with_id_parameters_validation(record, attribute, strategy)
+    end
+  end
+
+  def gradual_rollout_user_id_parameters_validation(record, attribute, strategy)
+    percentage = strategy.dig('parameters', 'percentage')
+    group_id = strategy.dig('parameters', 'groupId')
+
+    unless percentage.is_a?(String) && percentage.match(/\A[1-9]?[0-9]\z|\A100\z/)
+      error(record, attribute, 'percentage must be a string between 0 and 100 inclusive')
+    end
+
+    unless group_id.is_a?(String) && group_id.match(/\A[a-z]{1,32}\z/)
+      error(record, attribute, 'groupId parameter is invalid')
+    end
+  end
+
+  def user_with_id_parameters_validation(record, attribute, strategy)
+    user_ids = strategy.dig('parameters', 'userIds')
+    unless user_ids.is_a?(String) && !user_ids.match(/[\n\r\t]|,,/) && valid_ids?(user_ids.split(","))
+      error(record, attribute, "userIds must be a string of unique comma separated values each #{USERID_MAX_LENGTH} characters or less")
+    end
+  end
+
+  def valid_ids?(user_ids)
+    user_ids.uniq.length == user_ids.length &&
+    user_ids.all? { |id| valid_id?(id) }
+  end
+
+  def valid_id?(user_id)
+    user_id.present? &&
+    user_id.strip == user_id &&
+    user_id.length <= USERID_MAX_LENGTH
+  end
+
+  def error(record, attribute, msg)
+    record.errors.add(attribute, msg)
+    false
+  end
+end