nodejs writing protopayload in google-cloud/logging

How do we pass a protopayload union label using google-cloud/logging package in NodeJS?

So far i am able to write textPayload and jsonPayload in the logs.

Tried creating a protocol buffer using google-protobuf and also protobufjs and even tried protocol-buffer packages, but the payload is not seen in the logs when i do log.entry and log.write.

This is the code for writing logs
//writelogs.js

function writeLogEntryAdvanced (logName, options, callback) {
  var logging = Logging();
  var log = logging.log(logName);
var protobuf = require('protocol-buffers');
var fs = require('file-system');
// pass a proto file as a buffer/string or pass a parsed protobuf-schema object
var messages = protobuf(fs.readFileSync('test.proto'));
var buf = messages.Test.encode({
  num: 42,
  payload: 'hello world'
});
console.log(buf);
var entry = log.entry({ resource: options.resource }, buf);
  // See https://googlecloudplatform.github.io/google-cloud-node/#/docs/logging/latest/logging/log?method=write
  log.write(entry, function (err, apiResponse) {
    if (err) {
      return callback(err);
    }
    console.log('Wrote entry to log: %s', logName);
    return callback(null, apiResponse);
});
}

//test.proto

message Test {
  required float num  = 1;
  required string payload = 2;
}

the writing code is copied from nodejs-doc-samples from github with few changes of my own for protopayload. The sample logs writing was only for jsonPayload and textPayload.

via Rajat