src/main/java/com/google/devtools/build/lib/buildeventstream/transports/JsonFormatFileTransport.java

// Copyright 2017 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.buildeventstream.transports;

import com.google.devtools.build.lib.buildeventstream.ArtifactGroupNamer;
import com.google.devtools.build.lib.buildeventstream.BuildEvent;
import com.google.devtools.build.lib.buildeventstream.BuildEventContext;
import com.google.devtools.build.lib.buildeventstream.BuildEventProtocolOptions;
import com.google.devtools.build.lib.buildeventstream.BuildEventTransport;
import com.google.devtools.build.lib.buildeventstream.PathConverter;
import com.google.protobuf.InvalidProtocolBufferException;
import com.google.protobuf.util.JsonFormat;
import java.io.IOException;

/**
 * A simple {@link BuildEventTransport} that writes the JSON representation of the protocol-buffer
 * representation of the events to a file.
 */
public final class JsonFormatFileTransport extends FileTransport {
  private final BuildEventProtocolOptions options;
  private final PathConverter pathConverter;

  JsonFormatFileTransport(
      String path, BuildEventProtocolOptions options, PathConverter pathConverter)
          throws IOException {
    super(path);
    this.options = options;
    this.pathConverter = pathConverter;
  }

  @Override
  public String name() {
    return this.getClass().getSimpleName();
  }

  @Override
  public synchronized void sendBuildEvent(BuildEvent event, final ArtifactGroupNamer namer) {
    BuildEventContext converters =
        new BuildEventContext() {
          @Override
          public PathConverter pathConverter() {
            return pathConverter;
          }

          @Override
          public ArtifactGroupNamer artifactGroupNamer() {
            return namer;
          }

          @Override
          public BuildEventProtocolOptions getOptions() {
            return options;
          }
        };
    String protoJsonRepresentation;
    try {
      protoJsonRepresentation =
          JsonFormat.printer()
                  .omittingInsignificantWhitespace()
                  .print(event.asStreamProto(converters))
              + "\n";
    } catch (InvalidProtocolBufferException e) {
      // We don't expect any unknown Any fields in our protocol buffer. Nevertheless, handle
      // the exception gracefully and, at least, return valid JSON with an id field.
      protoJsonRepresentation =
          "{\"id\" : \"unknown\", \"exception\" : \"InvalidProtocolBufferException\"}\n";
    }
    write(protoJsonRepresentation);
  }
}