human/demo/nodejs/node-multiprocess.js

99 lines
4.2 KiB
JavaScript

/**
* Human demo for NodeJS
*
* Uses NodeJS fork functionality with inter-processing-messaging
* Starts a pool of worker processes and dispatch work items to each worker when they are available
* Uses node-multiprocess-worker.js for actual processing
*/
const fs = require('fs');
const path = require('path');
// eslint-disable-next-line import/no-extraneous-dependencies, node/no-unpublished-require
const log = require('@vladmandic/pilogger'); // this is my simple logger with few extra features
const child_process = require('child_process');
// note that main process does not import human or tfjs at all, it's all done from worker process
const workerFile = 'demo/nodejs/node-multiprocess-worker.js';
const imgPathRoot = './assets'; // modify to include your sample images
const numWorkers = 4; // how many workers will be started
const workers = []; // this holds worker processes
const images = []; // this holds queue of enumerated images
const t = []; // timers
let numImages;
// trigered by main when worker sends ready message
// if image pool is empty, signal worker to exit otherwise dispatch image to worker and remove image from queue
async function detect(worker) {
if (!t[2]) t[2] = process.hrtime.bigint(); // first time do a timestamp so we can measure initial latency
if (images.length === numImages) worker.send({ test: true }); // for first image in queue just measure latency
if (images.length === 0) worker.send({ exit: true }); // nothing left in queue
else {
log.state('Main: dispatching to worker:', worker.pid);
worker.send({ image: images[0] });
images.shift();
}
}
// loop that waits for all workers to complete
function waitCompletion() {
const activeWorkers = workers.reduce((any, worker) => (any += worker.connected ? 1 : 0), 0);
if (activeWorkers > 0) setImmediate(() => waitCompletion());
else {
t[1] = process.hrtime.bigint();
log.info('Processed:', numImages, 'images in', 'total:', Math.trunc(Number(t[1] - t[0]) / 1000000), 'ms', 'working:', Math.trunc(Number(t[1] - t[2]) / 1000000), 'ms', 'average:', Math.trunc(Number(t[1] - t[2]) / numImages / 1000000), 'ms');
}
}
function measureLatency() {
t[3] = process.hrtime.bigint();
const latencyInitialization = Math.trunc(Number(t[2] - t[0]) / 1000 / 1000);
const latencyRoundTrip = Math.trunc(Number(t[3] - t[2]) / 1000 / 1000);
log.info('Latency: worker initializtion: ', latencyInitialization, 'message round trip:', latencyRoundTrip);
}
async function main() {
process.on('unhandledRejection', (err) => {
// @ts-ignore // no idea if exception message is compelte
log.error(err?.message || err || 'no error message');
});
log.header();
log.info('FaceAPI multi-process test');
// enumerate all images into queue
const dir = fs.readdirSync(imgPathRoot);
for (const imgFile of dir) {
if (imgFile.toLocaleLowerCase().endsWith('.jpg')) images.push(path.join(imgPathRoot, imgFile));
}
numImages = images.length;
log.state('Enumerated images:', imgPathRoot, numImages);
t[0] = process.hrtime.bigint();
t[1] = process.hrtime.bigint();
t[2] = process.hrtime.bigint();
// manage worker processes
for (let i = 0; i < numWorkers; i++) {
// create worker process
workers[i] = await child_process.fork(workerFile, ['special']);
// parse message that worker process sends back to main
// if message is ready, dispatch next image in queue
// if message is processing result, just print how many faces were detected
// otherwise it's an unknown message
workers[i].on('message', (msg) => {
if (msg.ready) detect(workers[i]);
else if (msg.image) log.data('Main: worker finished:', workers[i].pid, 'detected faces:', msg.detected.face?.length, 'bodies:', msg.detected.body?.length, 'hands:', msg.detected.hand?.length, 'objects:', msg.detected.object?.length);
else if (msg.test) measureLatency();
else log.data('Main: worker message:', workers[i].pid, msg);
});
// just log when worker exits
workers[i].on('exit', (msg) => log.state('Main: worker exit:', workers[i].pid, msg));
// just log which worker was started
log.state('Main: started worker:', workers[i].pid);
}
// wait for all workers to complete
waitCompletion();
}
main();