BEP: add a JSON transport

As JSON is a widely supported format, also add a transport writing
the build events in JSON format. This will allow more tools to get
status reports about builds.

Change-Id: I7e5901cc65d927b93c8fc9bcd2d2baa7e707f09e
PiperOrigin-RevId: 155750964

4 files changed, 112 insertions, 0 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/buildeventstream/transports/BUILD b/src/main/java/com/google/devtools/build/lib/buildeventstream/transports/BUILD
index 661d416524..e75fb5c1b8 100644
--- a/src/main/java/com/google/devtools/build/lib/buildeventstream/transports/BUILD
+++ b/src/main/java/com/google/devtools/build/lib/buildeventstream/transports/BUILD
@@ -15,5 +15,6 @@ java_library(
         "//src/main/java/com/google/devtools/common/options",
         "//third_party:guava",
         "//third_party/protobuf:protobuf_java",
+        "//third_party/protobuf:protobuf_java_util",
     ],
 )
diff --git a/src/main/java/com/google/devtools/build/lib/buildeventstream/transports/BuildEventStreamOptions.java b/src/main/java/com/google/devtools/build/lib/buildeventstream/transports/BuildEventStreamOptions.java
index da3805e22a..cdc966082b 100644
--- a/src/main/java/com/google/devtools/build/lib/buildeventstream/transports/BuildEventStreamOptions.java
+++ b/src/main/java/com/google/devtools/build/lib/buildeventstream/transports/BuildEventStreamOptions.java
@@ -40,6 +40,14 @@ public class BuildEventStreamOptions extends OptionsBase {
   public String buildEventBinaryFile;
 
   @Option(
+    name = "experimental_build_event_json_file",
+    defaultValue = "",
+    optionUsageRestrictions = OptionUsageRestrictions.HIDDEN,
+    help = "If non-empty, write a JOSN serialisation of the build event protocol to that file."
+  )
+  public String buildEventJsonFile;
+
+  @Option(
     name = "experimental_build_event_text_file_path_conversion",
     defaultValue = "true",
     optionUsageRestrictions = OptionUsageRestrictions.HIDDEN,
@@ -61,6 +69,17 @@ public class BuildEventStreamOptions extends OptionsBase {
   )
   public boolean buildEventBinaryFilePathConversion;
 
+  @Option(
+    name = "experimental_build_event_json_file_path_conversion",
+    defaultValue = "true",
+    optionUsageRestrictions = OptionUsageRestrictions.HIDDEN,
+    help =
+        "Convert paths in the json file representation of the build event protocol to more "
+            + "globally valid URIs whenever possible; if disabled, the file:// uri scheme will "
+            + "always be used"
+  )
+  public boolean buildEventJsonFilePathConversion;
+
   public String getBuildEventTextFile() {
     return buildEventTextFile;
   }
@@ -69,6 +88,10 @@ public class BuildEventStreamOptions extends OptionsBase {
     return buildEventBinaryFile;
   }
 
+  public String getBuildEventJsonFile() {
+    return buildEventJsonFile;
+  }
+
   public boolean getBuildEventTextFilePathConversion() {
     return buildEventTextFilePathConversion;
   }
@@ -76,4 +99,8 @@ public class BuildEventStreamOptions extends OptionsBase {
   public boolean getBuildEventBinaryFilePathConversion() {
     return buildEventBinaryFilePathConversion;
   }
+
+  public boolean getBuildEventJsonFilePathConversion() {
+    return buildEventJsonFilePathConversion;
+  }
 }
diff --git a/src/main/java/com/google/devtools/build/lib/buildeventstream/transports/BuildEventTransportFactory.java b/src/main/java/com/google/devtools/build/lib/buildeventstream/transports/BuildEventTransportFactory.java
index b89017adc7..a28645dedb 100644
--- a/src/main/java/com/google/devtools/build/lib/buildeventstream/transports/BuildEventTransportFactory.java
+++ b/src/main/java/com/google/devtools/build/lib/buildeventstream/transports/BuildEventTransportFactory.java
@@ -55,6 +55,21 @@ public enum BuildEventTransportFactory {
               ? pathConverter
               : new NullPathConverter());
     }
+  },
+
+  JSON_TRANSPORT {
+    @Override
+    protected boolean enabled(BuildEventStreamOptions options) {
+      return !isNullOrEmpty(options.getBuildEventJsonFile());
+    }
+
+    @Override
+    protected BuildEventTransport create(
+        BuildEventStreamOptions options, PathConverter pathConverter) throws IOException {
+      return new JsonFormatFileTransport(
+          options.getBuildEventJsonFile(),
+          options.getBuildEventJsonFilePathConversion() ? pathConverter : new NullPathConverter());
+    }
   };
 
   /**
diff --git a/src/main/java/com/google/devtools/build/lib/buildeventstream/transports/JsonFormatFileTransport.java b/src/main/java/com/google/devtools/build/lib/buildeventstream/transports/JsonFormatFileTransport.java
new file mode 100644
index 0000000000..469319f6bb
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/buildeventstream/transports/JsonFormatFileTransport.java
@@ -0,0 +1,69 @@
+// 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.BuildEventConverters;
+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 PathConverter pathConverter;
+
+  JsonFormatFileTransport(String path, PathConverter pathConverter) throws IOException {
+    super(path);
+    this.pathConverter = pathConverter;
+  }
+
+  @Override
+  public String name() {
+    return this.getClass().getSimpleName();
+  }
+
+  @Override
+  public synchronized void sendBuildEvent(BuildEvent event, final ArtifactGroupNamer namer) {
+    BuildEventConverters converters =
+        new BuildEventConverters() {
+          @Override
+          public PathConverter pathConverter() {
+            return pathConverter;
+          }
+
+          @Override
+          public ArtifactGroupNamer artifactGroupNamer() {
+            return namer;
+          }
+        };
+    String protoJsonRepresentation;
+    try {
+      protoJsonRepresentation = JsonFormat.printer().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\" : \"InvlaidProtocolBufferException\"}\n";
+    }
+    writeData(protoJsonRepresentation.getBytes());
+  }
+}