// Copyright 2019 Google LLC.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//

syntax = "proto3";

package google.api;

option go_package = "google.golang.org/genproto/googleapis/api/serviceconfig;serviceconfig";
option java_multiple_files = true;
option java_outer_classname = "BackendProto";
option java_package = "com.google.api";
option objc_class_prefix = "GAPI";

// `Backend` defines the backend configuration for a service.
message Backend {
  // A list of API backend rules that apply to individual API methods.
  //
  // **NOTE:** All service configuration rules follow "last one wins" order.
  repeated BackendRule rules = 1;
}

// A backend rule provides configuration for an individual API element.
message BackendRule {
  // Path Translation specifies how to combine the backend address with the
  // request path in order to produce the appropriate forwarding URL for the
  // request.
  //
  // Path Translation is applicable only to HTTP-based backends. Backends which
  // do not accept requests over HTTP/HTTPS should leave `path_translation`
  // unspecified.
  enum PathTranslation {
    PATH_TRANSLATION_UNSPECIFIED = 0;

    // Use the backend address as-is, with no modification to the path. If the
    // URL pattern contains variables, the variable names and values will be
    // appended to the query string. If a query string parameter and a URL
    // pattern variable have the same name, this may result in duplicate keys in
    // the query string.
    //
    // # Examples
    //
    // Given the following operation config:
    //
    //     Method path:        /api/company/{cid}/user/{uid}
    //     Backend address:    https://example.cloudfunctions.net/getUser
    //
    // Requests to the following request paths will call the backend at the
    // translated path:
    //
    //     Request path: /api/company/widgetworks/user/johndoe
    //     Translated:
    //     https://example.cloudfunctions.net/getUser?cid=widgetworks&uid=johndoe
    //
    //     Request path: /api/company/widgetworks/user/johndoe?timezone=EST
    //     Translated:
    //     https://example.cloudfunctions.net/getUser?timezone=EST&cid=widgetworks&uid=johndoe
    CONSTANT_ADDRESS = 1;

    // The request path will be appended to the backend address.
    //
    // # Examples
    //
    // Given the following operation config:
    //
    //     Method path:        /api/company/{cid}/user/{uid}
    //     Backend address:    https://example.appspot.com
    //
    // Requests to the following request paths will call the backend at the
    // translated path:
    //
    //     Request path: /api/company/widgetworks/user/johndoe
    //     Translated:
    //     https://example.appspot.com/api/company/widgetworks/user/johndoe
    //
    //     Request path: /api/company/widgetworks/user/johndoe?timezone=EST
    //     Translated:
    //     https://example.appspot.com/api/company/widgetworks/user/johndoe?timezone=EST
    APPEND_PATH_TO_ADDRESS = 2;
  }

  // Selects the methods to which this rule applies.
  //
  // Refer to [selector][google.api.DocumentationRule.selector] for syntax details.
  string selector = 1;

  // The address of the API backend.
  string address = 2;

  // The number of seconds to wait for a response from a request.  The default
  // deadline for gRPC is infinite (no deadline) and HTTP requests is 5 seconds.
  double deadline = 3;

  // Minimum deadline in seconds needed for this method. Calls having deadline
  // value lower than this will be rejected.
  double min_deadline = 4;

  // The number of seconds to wait for the completion of a long running
  // operation. The default is no deadline.
  double operation_deadline = 5;

  PathTranslation path_translation = 6;

  // Authentication settings used by the backend.
  //
  // These are typically used to provide service management functionality to
  // a backend served on a publicly-routable URL. The `authentication`
  // details should match the authentication behavior used by the backend.
  //
  // For example, specifying `jwt_audience` implies that the backend expects
  // authentication via a JWT.
  oneof authentication {
    // The JWT audience is used when generating a JWT id token for the backend.
    string jwt_audience = 7;
  }
}
