| // Copyright 2020 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. |
| package com.google.devtools.build.lib.worker; |
| |
| import static java.nio.charset.StandardCharsets.UTF_8; |
| |
| import com.google.devtools.build.lib.worker.WorkerProtocol.WorkRequest; |
| import com.google.devtools.build.lib.worker.WorkerProtocol.WorkResponse; |
| import com.google.gson.stream.JsonReader; |
| import com.google.gson.stream.MalformedJsonException; |
| import com.google.protobuf.util.JsonFormat; |
| import com.google.protobuf.util.JsonFormat.Printer; |
| import java.io.BufferedReader; |
| import java.io.BufferedWriter; |
| import java.io.EOFException; |
| import java.io.IOException; |
| import java.io.InputStream; |
| import java.io.InputStreamReader; |
| import java.io.OutputStream; |
| import java.io.OutputStreamWriter; |
| |
| /** An implementation of a Bazel worker using JSON to communicate with the worker process. */ |
| final class JsonWorkerProtocol implements WorkerProtocolImpl { |
| /** Reader for reading the WorkResponse. */ |
| private final JsonReader reader; |
| /** Printer for printing the WorkRequest */ |
| private final Printer jsonPrinter; |
| /** Writer for writing the WorkRequest to the worker */ |
| private final BufferedWriter jsonWriter; |
| |
| JsonWorkerProtocol(OutputStream workersStdin, InputStream workersStdout) { |
| jsonPrinter = JsonFormat.printer().omittingInsignificantWhitespace(); |
| jsonWriter = new BufferedWriter(new OutputStreamWriter(workersStdin, UTF_8)); |
| reader = new JsonReader(new BufferedReader(new InputStreamReader(workersStdout, UTF_8))); |
| reader.setLenient(true); |
| } |
| |
| @Override |
| public void putRequest(WorkRequest request) throws IOException { |
| // WorkRequests are serialized according to ndjson spec. |
| // https://github.com/ndjson/ndjson-spec |
| jsonPrinter.appendTo(request, jsonWriter); |
| jsonWriter.append(System.lineSeparator()); |
| jsonWriter.flush(); |
| } |
| |
| @Override |
| public WorkResponse getResponse() throws IOException { |
| boolean interrupted = Thread.interrupted(); |
| try { |
| return parseResponse(); |
| } finally { |
| if (interrupted) { |
| Thread.currentThread().interrupt(); |
| } |
| } |
| } |
| |
| private WorkResponse parseResponse() throws IOException { |
| Integer exitCode = null; |
| String output = null; |
| Integer requestId = null; |
| try { |
| reader.beginObject(); |
| while (reader.hasNext()) { |
| String name = reader.nextName(); |
| switch (name) { |
| case "exitCode": |
| if (exitCode != null) { |
| throw new IOException("Work response cannot have more than one exit code"); |
| } |
| exitCode = reader.nextInt(); |
| break; |
| case "output": |
| if (output != null) { |
| throw new IOException("Work response cannot have more than one output"); |
| } |
| output = reader.nextString(); |
| break; |
| case "requestId": |
| if (requestId != null) { |
| throw new IOException("Work response cannot have more than one requestId"); |
| } |
| requestId = reader.nextInt(); |
| break; |
| default: |
| // As per https://bazel.build/docs/creating-workers#work-responses, |
| // unknown fields are ignored. |
| reader.skipValue(); |
| } |
| } |
| reader.endObject(); |
| } catch (MalformedJsonException | EOFException | IllegalStateException e) { |
| throw new IOException("Could not parse json work request correctly", e); |
| } |
| |
| WorkResponse.Builder responseBuilder = WorkResponse.newBuilder(); |
| |
| if (exitCode != null) { |
| responseBuilder.setExitCode(exitCode); |
| } |
| if (output != null) { |
| responseBuilder.setOutput(output); |
| } |
| if (requestId != null) { |
| responseBuilder.setRequestId(requestId); |
| } |
| |
| return responseBuilder.build(); |
| } |
| |
| @Override |
| public void close() throws IOException { |
| reader.close(); |
| jsonWriter.close(); |
| } |
| } |