Nodejs工作线程实现问题

Question

我有一个 test1.ts 文件，我试图将一些 CPU 密集型图像处理工作卸载到工作线程。下面是文件 test1.ts 的代码及其在另一个文件中的调用。该项目是一个 NodeJS ExpressJS Web 服务器。

test1.ts 文件

const { Worker, workerData,isMainThread, parentPort } = require("worker_threads");
const { generateUrls } =  require("./util");
const Jimp = require("jimp");
const { uploadImage } =  require("../imageStorage");

if (!isMainThread){
    mainWork()
    .finally(() => {
        parentPort?.postMessage({});
    })
} 

async function mainWork() {
  const { accountId, imageBuffer, imageNames, docUrls, meta } = workerData;

  try {
    const { imageIndex, imageType } = meta;
    const imageName = imageNames.imageName + `_${imageType}_` + `${imageIndex || ""}` + ".png";
    docUrls[imageType === "heatmap" ? "heatmapUrls" : "normalUrls"][imageIndex] = generateUrls(
      accountId,
      imageName
    );

    const maxWidth = 764;
    const maxHeight = 2000;
    const image = await Jimp.read(imageBuffer);
    const originalWidth = image.bitmap.width;
    const originalHeight = image.bitmap.height;

    // Calculate the aspect ratio
    const aspectRatio = originalWidth / originalHeight;

    // Determine the new dimensions based on the desired maximum width and height
    let newWidth = originalWidth;
    let newHeight = originalHeight;

    if (originalWidth > maxWidth) {
      newWidth = maxWidth;
      newHeight = maxWidth / aspectRatio;
    }

    if (newHeight > maxHeight) {
      newHeight = maxHeight;
      newWidth = maxHeight * aspectRatio;
    }

    image.resize(newWidth, newHeight);
    image.quality(100);
    const newBuffer = await image.getBufferAsync(Jimp.MIME_PNG);
    await uploadImage(newBuffer, accountId, imageName);

    return { imageName, docUrls }; // Return the result
  } catch (error) {
    console.error("Error resizing and converting image:", error);
    return Promise.reject(error); // Reject the Promise with the error
  }
}

function imageResizeCropUpload(
  accountId: any,
  imageBuffer: any,
  imageNames: any,
  docUrls: any,
  meta: any
): Promise<void> {
  return new Promise((resolve, reject) => {
    const worker = new Worker(__filename, {
      workerData: {
        accountId,
        imageBuffer,
        imageNames,
        docUrls,
        meta
      }
    });

    worker.on("message", (result:any) => {
      resolve(result); // Resolve the Promise with the result
    });

    worker.on("error", (e:any) => {
      reject(e);
    });

    worker.on("exit", (code:any) => {
      if (code !== 0) reject(new Error(`Worker stopped with exit code ${code}`));
    });
  });
}

export default imageResizeCropUpload

一些其他文件.ts

import imageResizeCropUpload from './test1'
uploadPromises.push(
            imageResizeCropUpload(accountId, buffers[0], imageNames, docUrls, {
                imageIndex: 0,
                imageType: "heatmap"
            })
);

现在发生了什么，我不知道，但我得到的只是“Worker stop with exit code 1”，并出现错误，因为 process.send() 不是函数。我在网上查看但找不到任何东西。请帮助我，我是第一次使用工作线程。

Answer 1

process.send()

是在使用

child_process.fork()

创建的 Node.js 进程中使用的函数。该函数允许子进程与其父进程进行通信。在您的场景中，您遇到错误是因为您使用的是worker_threads，而不是child_process。工作线程模块没有

process.send()

函数，因为工作线程通过不同的机制与其主线程通信，特别是使用parentPort.PostMessage()

https://nodejs.org/api/worker_threads.html

https://nodejs.org/api/child_process.html

对

process.send()

的调用可能在Jimp或imageStorage中，如果是这种情况，您可能需要更改为使用子进程。