Support for running in worker threads

[OmgImAlexis]

With the default options the following doesn't work.

const python = pythonBridge();

Instead we get the following error. If I set stdio to ['ignore', 'pipe', 'pipe'] it works without an issue. It'd be nice to either detect the worker thread and use different defaults or catch the error and show a nicer message.

TypeError [ERR_INVALID_OPT_VALUE]: The value "WritableWorkerStdio {
  _writableState: WritableState {
    objectMode: false,
    highWaterMark: 16384,
    finalCalled: false,
    needDrain: false,
    ending: false,
    ended: false,
    finished: false,
    destroyed: false,
    decodeStrings: false,
    defaultEncoding: 'utf8',
    length: 97,
    writing: true,
    corked: 0,
    sync: false,
    bufferProcessing: false,
    onwrite: [Function: bound onwrite],
    writecb: [Function],
    writelen: 97,
    bufferedRequest: null,
    lastBufferedRequest: null,
    pendingcb: 1,
    prefinished: false,
    errorEmitted: false,
    emitClose: true,
    autoDestroy: false,
    bufferedRequestCount: 0,
    corkedRequestsFree: {
      next: null,
      entry: null,
      finish: [Function: bound onCorkedFinish]
    }
  },
  writable: true,
  _events: [Object: null prototype] {},
  _eventsCount: 0,
  _maxListeners: undefined,
  [Symbol(kPort)]: MessagePort {
    active: true,
    refed: true,
    _events: [Object: null prototype] {
      newListener: [Function],
      removeListener: [Function],
      message: [Function]
    },
    _eventsCount: 3,
    [Symbol(kWaitingStreams)]: 1
  },
  [Symbol(kName)]: 'stdout',
  [Symbol(kWritableCallbacks)]: [ [Function: bound onwrite] ]
}" is invalid for option "stdio"
    at internal/child_process.js:996:13
    at Array.reduce (<anonymous>)
    at getValidStdio (internal/child_process.js:922:17)
    at ChildProcess.spawn (internal/child_process.js:340:11)
    at Object.spawn (child_process.js:535:9)
    at Function.pythonBridge (/Users/xo/code/scratch/node_modules/python-bridge/index.js:22:28)
    at PostProcessor.<anonymous> (/Users/xo/code/scratch/workers/post-processor.ts:91:24)
    at step (/Users/xo/code/scratch/workers/post-processor.ts:50:23)
    at Object.next (/Users/xo/code/scratch/workers/post-processor.ts:31:53)
    at /Users/xo/code/scratch/workers/post-processor.ts:25:71
    at new Promise (<anonymous>)
    at __awaiter (/Users/xo/code/scratch/workers/post-processor.ts:21:12)
    at PostProcessor.guessit (/Users/xo/code/scratch/workers/post-processor.ts:96:16)
    at /Users/xo/code/scratch/workers/post-processor.ts:78:29
    at Array.map (<anonymous>)
    at PostProcessor.<anonymous> (/Users/xo/code/scratch/workers/post-processor.ts:77:36)

[munro]

wow that's no good, can you share a script I can run to reproduce this? I'd greatly accept a PR to fix this—I haven't used worker threads in Node.js

[munro]

bump @OmgImAlexis do you have a small snippet for me to reproduce this?

I haven't really used worker threads in Node.js, though I guess if I just copy the documentation and call const python = pythonBridge(); it will reproduce—but a snippet to reproduce would be nice!

If I try to think what the issue is, I believe worker threads uses FD 0 on the worker for IPC to the main process—or something like that. I think I'd really have to dig into the how worker threads are working though, and think a bit about a good solution that doesn't end up causing more problems—and then have the automated testing run for single process / main process & worker process. WORK 😫