// Copyright 2015 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.

syntax = "proto3";

package blaze.worker;

option java_package = "com.google.devtools.build.lib.worker";

// An input file.
message Input {
  // The path in the file system where to read this input artifact from. This is
  // either a path relative to the execution root (the worker process is
  // launched with the working directory set to the execution root), or an
  // absolute path.
  string path = 1;

  // A hash-value of the contents. The format of the contents is unspecified and
  // the digest should be treated as an opaque token.
  bytes digest = 2;
}

// This represents a single work unit that Blaze sends to the worker.
message WorkRequest {
  repeated string arguments = 1;

  // The inputs that the worker is allowed to read during execution of this
  // request.
  repeated Input inputs = 2;

  // Each WorkRequest must have either a unique
  // request_id or request_id = 0. If request_id is 0, this WorkRequest must be
  // processed alone (singleplex), otherwise the worker may process multiple
  // WorkRequests in parallel (multiplexing). As an exception to the above, if
  // the cancel field is true, the request_id must be the same as a previously
  // sent WorkRequest. The request_id must be attached unchanged to the
  // corresponding WorkResponse. Only one singleplex request may be sent to a
  // worker at a time.
  int32 request_id = 3;

  // EXPERIMENTAL: When true, this is a cancel request, indicating that a
  // previously sent WorkRequest with the same request_id should be cancelled.
  // The arguments and inputs fields must be empty and should be ignored.
  bool cancel = 4;
}

// The worker sends this message to Blaze when it finished its work on the
// WorkRequest message.
message WorkResponse {
  int32 exit_code = 1;

  // This is printed to the user after the WorkResponse has been received and is
  // supposed to contain compiler warnings / errors etc. - thus we'll use a
  // string type here, which gives us UTF-8 encoding.
  string output = 2;

  // This field must be set to the same request_id as the WorkRequest it is a
  // response to. Since worker processes which support multiplex worker will
  // handle multiple WorkRequests in parallel, this ID will be used to
  // determined which WorkerProxy does this WorkResponse belong to.
  int32 request_id = 3;

  // EXPERIMENTAL When true, indicates that this response was sent due to
  // receiving a cancel request. The exit_code and output fields should be empty
  // and will be ignored. Exactly one WorkResponse must be sent for each
  // non-cancelling WorkRequest received by the worker, but if the worker
  // received a cancel request, it doesn't matter if it replies with a regular
  // WorkResponse or with one where was_cancelled = true.
  bool was_cancelled = 4;
}