// Copyright 2016 The Bazel Authors. All rights reserved.
//
// 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.
//
// This file contains the protocol used to communicate between the Bazel client
// and the server. At a high level clients may call the CommandServer.run rpc
// to initiates a Bazel command and CommandServer.cancel to cancel an in-flight
// command. CommandServer.ping may be used to check for server liveness without
// executing any commands. See documentation of individual messages for more
// details.
syntax = "proto3";

package command_server;

option java_package = "com.google.devtools.build.lib.server";
option java_outer_classname = "CommandProtos";

// Passed to CommandServer.run to initiate execution of a Bazel command.
message RunRequest {
  // Request cookie from the output base of the server. This serves as a
  // rudimentary form of mutual authentication.
  string cookie = 1;

  // Command and command arguments. Does not include startup arguments.
  repeated bytes arg = 2;

  // Tells the server whether or not the client is willing to wait for any
  // concurrent in-flight request to complete (there are many commands which
  // may not run concurrently). If false and there are in-flight requests then
  // the server will return an error immediately.
  bool block_for_lock = 3;

  // A simple description of the client for reporting purposes. This value is
  // required.
  string client_description = 4;
}

// Contains metadata and result data for a command execution.
message RunResponse {
  // Request cookie from the output base of the server. This serves as a
  // rudimentary form of mutual authentication. Set on every response.
  string cookie = 1;

  // Standard out of the command, chunked. May be empty.
  bytes standard_output = 2;

  // Standard error of the command, chunked. May be empty.
  bytes standard_error = 3;

  // Whether this is the last message of the stream, signals that exit_code is
  // valid.
  bool finished = 4;

  // The exit code of the command, only valid when finished is set.
  int32 exit_code = 5;

  // Randomly generated command identifier, this may be used to cancel execution
  // of the command by issuing a cancel call. This should be sent to the client
  // as soon as possible. This is not required to be set (non-empty) on every
  // response.
  string command_id = 6;
}

// Passed to CommandServer.cancel to initiate graceful cancellation of an
// in-flight command.
message CancelRequest {
  // The client request cookie (see RunRequest.cookie).
  string cookie = 1;

  // The id of the command to cancel.
  string command_id = 2;
}

message CancelResponse {
  // The server response cookie (see RunResponse.cookie).
  string cookie = 1;
}

// Passed to CommandServer.ping to initiate a ping request.
message PingRequest {
  // The client request cookie (see RunRequest.cookie).
  string cookie = 1;
}

message PingResponse {
  // The server response cookie (see RunResponse.cookie).
  string cookie = 1;
}

service CommandServer {
  // Run a Bazel command. See documentation of argument/return messages for
  // details.
  rpc Run (RunRequest) returns (stream RunResponse) {}

  // Cancel a currently running Bazel command. May return before the run command
  // actually terminates.
  rpc Cancel (CancelRequest) returns (CancelResponse) {}

  // Does not do anything. Used for liveness check.
  rpc Ping (PingRequest) returns (PingResponse) {}
}