How to use TypeORM or Prisma inside worker ?

[ghostlexly]

Hey,

I'm using TypeORM. How i can use "await" inside .exec() function ? I want to wait for the results from my database inside a worker.

import { Connection } from "@/entities/Connection";

await queues.exec(() => {
      const connections = await Connection.find({ where: { facebook: Not(null) } });
    }, []);

[josdejong]

If this is a question about TypeORM please ask at the project itself. You can ask questions here about workerpool.

[ghostlexly]

It's about workerpool, i want to find a way to use Async methods inside workerpool, like typeorm's async methods, it's just an example

[josdejong]

You can "just" use async functions and return Promise like results.

Here is an example: https://jsbin.com/semafew/edit?html,console

[ghostlexly]

Here is the problem i have with the same code:

import workerpool from "workerpool";
import { User } from "./entities/User";
export const queues = workerpool.pool({
  maxWorkers: require("os").cpus().length,
});

  async function getUsers() {
    function getResults() {
      return new Promise(async (resolve, reject) => {
        resolve(await User.find());
      });
    }

    return await getResults();
  }

  const test = await queues.exec(getUsers, []);

User is the entity from TypeORM.

crosslikes-backend-1  | ReferenceError: User_1 is not defined
crosslikes-backend-1  |     at eval (eval at run (/usr/src/app/node_modules/workerpool/src/worker.js:105:11), <anonymous>:6:25)
crosslikes-backend-1  |     at new Promise (<anonymous>)
crosslikes-backend-1  |     at getResults (eval at run (/usr/src/app/node_modules/workerpool/src/worker.js:105:11), <anonymous>:5:20)
crosslikes-backend-1  |     at getUsers (eval at run (/usr/src/app/node_modules/workerpool/src/worker.js:105:11), <anonymous>:9:22)
crosslikes-backend-1  |     at Function.eval (eval at run (/usr/src/app/node_modules/workerpool/src/worker.js:105:11), <anonymous>:10:8)
crosslikes-backend-1  |     at Function.run (/usr/src/app/node_modules/workerpool/src/worker.js:106:12)
crosslikes-backend-1  |     at MessagePort.<anonymous> (/usr/src/app/node_modules/workerpool/src/worker.js:157:27)
crosslikes-backend-1  |     at [nodejs.internal.kHybridDispatch] (node:internal/event_target:737:20)
crosslikes-backend-1  |     at exports.emitMessage (node:internal/per_context/messageport:23:28)

[josdejong]

The function getUsers references external code User. The function is serialized, send to the worker, and then deserialized, and therefore must be completely standalone. In this case, on the worker side there is no User. You'll have to either embed this class in the function, or create a dedicated worker.

[ghostlexly]

Is there a way to call the dedicated worker with a class name ? i try to avoid file paths like this

__dirname + '/myWorker.js'

Thanks for the solutions

[josdejong]

No, just like a regular import you need to point to the path where the worker script can be found.