Error: 'Module did not self-register' using worker_threads in v12

[shuckc]

If redis-fast-driver is requireed by both the 'main thread' and also a worker thread, the 2nd attempt fails and triggers an Error in the cjs loader.

Reproducing code - worker.js:

/* eslint-disable no-console */
const Redis = require('redis-fast-driver');
const {Worker, isMainThread} = require('worker_threads');

if (isMainThread) {
  console.log('Main Thread');
  const worker = new Worker(__filename);
  worker.on('message', console.log);
} else {
  console.log(`in worker ${__filename}`);
}
console.log('first pass done');

Output:

$ node worker.js 
Main Thread
first pass done

events.js:173
      throw er; // Unhandled 'error' event
      ^
Error: Module did not self-register.
    at Object.Module._extensions..node (internal/modules/cjs/loader.js:800:18)
    at Module.load (internal/modules/cjs/loader.js:628:32)
    at Function.Module._load (internal/modules/cjs/loader.js:555:12)
    at Module.require (internal/modules/cjs/loader.js:666:19)
    at require (internal/modules/cjs/helpers.js:16:16)
    at Object.<anonymous> (/Users/shuckc/project1/node_modules/redis-fast-driver/index.js:2:15)
    at Module._compile (internal/modules/cjs/loader.js:759:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:770:10)
    at Module.load (internal/modules/cjs/loader.js:628:32)
    at Function.Module._load (internal/modules/cjs/loader.js:555:12)
Emitted 'error' event at:
    at Worker.[kOnErrorMessage] (internal/worker.js:161:10)
    at Worker.[kOnMessage] (internal/worker.js:171:37)
    at MessagePort.<anonymous> (internal/worker.js:104:57)
    at MessagePort.emit (events.js:196:13)
    at MessagePort.onmessage (internal/worker/io.js:68:8)

It seems to me there might be some additional work on the C++ side to have a module support being required twice. This is an issue even if the worker does not invoke the client on the codepath, just requires it.

[shuckc]

Seems relevant:
Another module with same issue: schroffl/node-lzo#10
Reported fix: nodejs/node#21783 (comment)

Node docs for context-aware-addons:
https://github.com/nodejs/node/blob/master/doc/api/addons.md#context-aware-addons

[h0x91b]

Thanks, I'll try to fix it

[h0x91b]

Sadly but, not enough to just use NODE_MODULE_INIT (BTW this was hard to do)

Seems like I must migrate from NaN to N-API via node-addon-api to correctly support workers, this will take little bit time and may not be stable.

Will update here.

[FlorianMaak]

Any Updates on this?

[h0x91b]

No, need to completely rewrite C++ part of the module. So actually it will be a new driver. Sadly but I don't have enough free time now to rewrite and test it.