dns_manager.rb

module API::Clients
  class DnsManager < Base
    def initialize(url)
      headers = {
        "Accept"       => "application/json",
        "Content-Type" => "application/json",
        "Request-Id"   => API::RequestStore.request_ids,
        "X-Request-Id" => API::RequestStore.request_id,
      }
      super(url, "heroku-dns-manager", headers: headers)
    end

    def create_cname(domain, target)
      send_request(
        params(
          action: :CREATE,
          domain: domain,
          target: target
        )
      )
    end

    def delete_cname(domain, target)
      send_request(
        params(
          action: :DELETE,
          domain: domain,
          target: target
        )
      )
    end

    private

    def params(action:, domain:, target:, type:)
      case type
      when "CNAME"
        params_cname(action: action, domain: domain, target: target)
      when "ALIAS"
        params_alias(action: action, domain: domain, target: target)
      end
    end

    def params_cname(action:, domain:, target:)
      {
        change: {
          :action               => action,
          "resource-record-set" => {
            :name              => domain,
            :type              => "CNAME",
            :ttl               => "600",
            "resource-records" => [
              {
                value: target
              }
            ]
          }
        }
      }
    end

    def params_alias(action:, domain:, target:)
      {
        change: {
          :action               => "UPSERT",
          "resource-record-set" => {
            :name          => domain,
            :type          => "A",
            "alias-target" => {
              "dns-name"               => target,
              "evaluate-target-health" => false
            }
          }
        }
      }
    end

    def send_request(p)
      request(
        method: :post,
        body:    MultiJson.encode(p),
        expects: [201],
        path:    "/requests/#{API::Config.heroku_stable_dns_domain}"
      )
    end
  end
end