V8 error when running Connector in a NodeJS worker thread

[Wilbert van de Ridder]

Issue

In our application we use a number of worker threads to handle certain services. One of them should run the DDS interface. We notice that when running the connector from a worker thread, a V8 error pops up, which seems related to ffi. This error does not pop up when running the rti connector sample code from the main thread.

Code

Main thread

console.log(`[Operator] About to start DDS worker ${__dirname}/worker/${ddsWorkerFile}`);
this.ddsWorker = new Worker(`${__dirname}/worker/${ddsWorkerFile}`, {
   workerData,
});

Import script

const path = require("path");
require(path.resolve(__dirname, "./dds-worker.ts"));

Worker

const { isMainThread, parentPort, workerData } = require("worker_threads");

const sleep = require('sleep')
const path = require('path')
const rti = require('rticonnextdds-connector')
const configFile = path.join(process.cwd(), '/../../dds/ShapeExample.xml')
console.log("[DDS worker] Init!", configFile);

const run = async () => {
  const connector = new rti.Connector('MyParticipantLibrary::MyPubParticipant', configFile)
  const output = connector.getOutput('MyPublisher::MySquareWriter')
  try {
    console.log('Waiting for subscriptions...')
    await output.waitForSubscriptions()

    console.log('Writing...')
    for (let i = 0; i < 500; i++) {
      output.instance.setNumber('x', i)
      output.instance.setNumber('y', i * 2)
      output.instance.setNumber('shapesize', 30)
      output.instance.setString('color', 'BLUE')
      output.write()

      sleep.msleep(50)
    }

    console.log('Exiting...')
    // Wait for all subscriptions to receive the data before exiting
    await output.wait()
  } catch (err) {
    console.log('Error encountered: ' + err)
  }
  connector.close()
}

if (!isMainThread) {
  try {
    console.log("[DDS worker] Starting...");
    run();
  } catch (e) {
    console.error(e);
    setTimeout(() => {
      console.log("[DDS worker] Shutting down..");
    }, 500);
  }
}

Error

[DDS worker] Init! D:\Github\amr-simulator\dds\ShapeExample.xml
FATAL ERROR: HandleScope::HandleScope Entering the V8 API without proper locking in place
 1: 00007FF7185BF43A v8::internal::GCIdleTimeHandler::GCIdleTimeHandler+4618
 2: 00007FF71856D186 uv_loop_fork+86646
 3: 00007FF71856DC4D uv_loop_fork+89405
 4: 00007FF7189987D7 v8::HandleScope::Initialize+103
 5: 00007FF7185E2EA9 node::CallbackScope::~CallbackScope+217
 6: 00007FF7185E3209 node::CallbackScope::~CallbackScope+1081
 7: 00007FF7185E36B6 node::MakeCallback+150
 8: 00007FFCAC3C1640 Nan::Callback::Call+368 [d:\github\amr-simulator\src\backend\node_modules\nan\nan.h]:L1746
 9: 00007FFCAC3C4440 FFI::FinishAsyncFFICall+256 [d:\github\amr-simulator\src\backend\node_modules\ffi\src\ffi.cc]:L370
10: 00007FF718612E50 uv_timer_set_repeat+1824
11: 00007FF718612DC7 uv_timer_set_repeat+1687
12: 00007FF71860E294 uv_dlerror+2452
13: 00007FF71860F068 uv_run+232
14: 00007FF71859A381 node::Init+2097
15: 00007FF71859AB57 node::Start+1159
16: 00007FF7190F408C v8::internal::AsmJsScanner::IsNumberStart+127292
17: 00007FFCB25C7034 BaseThreadInitThunk+20
18: 00007FFCB2DBD241 RtlUserThreadStart+33

System

OS: Windows 20H2 (OS Build 19042.804)
Node version: v11.15.0
Connector: "rticonnextdds-connector": "^1.0.0"

Related

• node-ffi-napi/node-ffi-napi#17

[Wilbert van de Ridder]

Installing rticonnextdds-connector-js from the develop branch shows that in the (upcoming?) release the issue seems to be fixed. It seems to be fixed in node-ffi-napi here: node-ffi-napi/node-ffi-napi#50. However, I did need to use node version 12.13.0 instead of 11.15.0 to get it to work.

[Sam]

This should now be resolved in release 1.1.0, where support for node v12 is added.