gitlab-org--gitlab-foss/app/controllers/concerns/requires_whitelisted_monitoring_client.rb

module RequiresWhitelistedMonitoringClient
  extend ActiveSupport::Concern
  included do
    before_action :validate_ip_whitelisted!
  end

  private

  def validate_ip_whitelisted!
    render_404 unless client_ip_whitelisted? || token_valid?
  end

  def client_ip_whitelisted?
    Settings.monitoring.ip_whitelist.any? { |e| e.include?(Gitlab::RequestContext.client_ip) }
  end
  
  def token_valid?
    token = params[:token].presence || request.headers['TOKEN']
    token.present? &&
      ActiveSupport::SecurityUtils.variable_size_secure_compare(
        token,
        current_application_settings.health_check_access_token
      )
  end

  def render_404
    render file: Rails.root.join('public', '404'), layout: false, status: '404'
  end
end