system_api/dbus/update_engine/update_engine.proto

// Copyright 2018 The Chromium OS Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

syntax = "proto3";

option optimize_for = LITE_RUNTIME;

package chromeos_update_engine;

// This contains info Update Engine needs to download a DLC (Downloadable
// Content).
// https://chromium.googlesource.com/chromiumos/platform2/+/HEAD/dlcservice
message DlcInfo {
  // ID of the DLC.
  // This has to be set.
  // dlc_id is used to contruct DLC install path and Omaha App ID.
  // Omaha App ID is used to query update from Omaha server. Omaha responds
  // with payload that corresponds to the App ID based on a preset rule.
  // Omaha respponds with error if the provided App ID does not exist on
  // Omaha.
  string dlc_id = 1;
}

// This is the message passed in Update Engine via AttemptInstall from
// dlcservice.
//
// The general flow is as follows:
// 1. dlcservice parses rootfs for a list of supported DLC id.
// 2. dlcservice receives request to install one or more DLC.
// 3. dlcservice constructs DlcParameter based on supported DLC id and sends
//    the message to Update Engine via AttemptInstall D-Bus API (restricted to
//    be accessible by dlcservice only). If this runs on a DUT, omaha_url has to
//    be set to avoid querying to the real Omaha server.
// 4. Update Engine receives the DlcParameters message and checks the validity
//    of the request (there has to be at least one item in dlc_infos and each
//    item can not have empty field).
// 5. Update Engine constructs Omaha query and continue installation operations.
message DlcParameters {
  // A list of DLC info to install.
  repeated DlcInfo dlc_infos = 1;
  // Omaha URL to query for update.
  string omaha_url = 2;
}