andywer/threads.js

Debugging with ts-node and VS code

Open

#274 opened on Jun 30, 2020

 (4 comments) (0 reactions) (0 assignees)TypeScript (173 forks)github user discovery
help wantedquestion

Repository metrics

Stars
 (3,531 stars)
PR merge metrics
 (No merged PRs in 30d)

Description

There seems to be an issue with running threads.js with node -r ts-node/register. Description of how the issue appears: Launching application through VS Code debugger that has threads.js method call that spawns a new worker. After the first call to such method, everything works fine - worker returns. Subsequent calls throws

Error: Timeout: Did not receive an init message from worker after 10000ms. Make sure the worker calls expose().
    at Timeout._onTimeout (E:\something\node_modules\threads\dist\master\spawn.js:34:53)
    at listOnTimeout (internal/timers.js:531:17)
    at processTimers (internal/timers.js:475:7)

Details: tsconfig.json

{
  "compilerOptions": {
    "skipLibCheck": true,
    "lib": [
      "dom",
      "es5",
      "es6",
      "es7",
      "es2015",
      "es2016",
      "es2017",
      "es2018",
      "esnext"
    ],
    "module": "commonjs",
    "moduleResolution": "node",
    "pretty": true,
    "sourceMap": false,
    "target": "es6",
    "outDir": "./dist",
    "baseUrl": "./",
    "declaration": true,
    },
    "forceConsistentCasingInFileNames": false,
    "noImplicitReturns": true,
    "noImplicitAny": true,
    "strict": true,
    "strictNullChecks": true,
    "emitDecoratorMetadata": true,
    "experimentalDecorators": true,
    "resolveJsonModule": true,
    "noUnusedLocals": false,
    "esModuleInterop": true,
    "typeRoots": [
      "./node_modules/@types",
      "./src/@types"
    ]
  },
  "include": [
    "./src/*.ts",
    "./src/**/*.ts",
    "./src/**/*.d.ts"
  ],
  "exclude": [
    "node_modules"
  ],
  "typeAcquisition": {
    "enable": true
  }
}

vs code debuggers launch.json

{
  "version": "0.2.0",
  "configurations": [
    {
      "name": "API",
      "type": "node",
      "request": "launch",
      "args": [
        "${workspaceFolder}/src/Server.ts"
      ],
      "runtimeArgs": [
        "-r",
        "ts-node/register"
      ],
      "cwd": "${workspaceRoot}",
      "protocol": "inspector",
      "internalConsoleOptions": "openOnSessionStart",
    }
  ]
}

Sample code Controller with the worker method

export default class Controller {
    worker_pool: WorkerPool.Pool<WorkerPool.ModuleThread<Worker>>
    constructor() {
        this.story_worker_pool = Pool(() => spawn<Worker>(new Worker("./worker.worker")))
    }
   async method() {
        return this.worker_pool.queue(async worker => {
            processed_items = await worker.processItems(items)
        })
   }
}

worker

export class Worker implements WorkerModule<any>  {
    [x: string]: WorkerFunction;

    public processItems(items): any[] {
        items.map((story, index) => {
            // do math
        });
        return items
    }
}
expose(Worker as any)

How this issue could be resolved? Everything works fine with the sample code after building the source code and running it with node

Contributor guide