Example performance test for CSP Channels

channel-push-test.js

/*

This is a simplified excerpt of a performance test used for channel throughput.
It reads from a file into an inputChannel, and pushes it's data through two other channels.

You can tune the test by how many bytes are sent at a time, and how long to wait between sending more data.

usage
$node channel-push-test.js my_video.mp4
*/

var parseArgs = require('minimist');
var fs = require('fs');
var csp = require('js-csp');

var CHUNK_SIZE = 10;
var WAIT_TIME = 0;
var buff = new Buffer(CHUNK_SIZE);

var args = parseArgs(process.argv.slice(2));
var file = args._[0];

var fileReadInterval = -1;

var transmuxer = {
    inputChannel: new csp.chan(),
    audio: new csp.chan(),
    video: new csp.chan()
};


fs.open(file, 'r', function(err, fd) {
    if (err) {
        console.log('Error opening file: ', file);
        console.log(err.message);
        return;
    }

    fileReadInterval = setInterval(pushSomeBytes.bind(null, fd), WAIT_TIME);
});

function pushSomeBytes(fd) {
    fs.read(fd, buff, 0, buff.length, null, function(err, bytesRead, buffer) {
        if (err) {
            console.log(err.message);
            return;
        }

        // If it didn't read a full amount of bytes, remove noise
        var data = buffer.slice(0, bytesRead);

        csp.putAsync(transmuxer.inputChannel, data);

        if (bytesRead < buff.length) {
            transmuxer.inputChannel.close();
            fs.close(fd);
            clearInterval(fileReadInterval);
        }
    });
}



csp.go(function*() {
    var length = 0;
    var unit;
    while (csp.CLOSED !== (unit = yield csp.take(transmuxer.video))) {
        length += unit.length;
    }
    console.log('h264 data of length ' , length);
});

csp.go(function*() {
    var length = 0;
    var unit;
    while (csp.CLOSED !== (unit = yield csp.take(transmuxer.audio))) {
        length += unit.length;
    }
    console.log('audio data of length ' , length);
});


csp.go(function*() {
    var unit;
    while (csp.CLOSED !== (unit = yield csp.take(transmuxer.inputChannel))) {
        if (Math.random() > 0.5) {
            yield csp.put(transmuxer.video, unit);
        } else {
            yield csp.put(transmuxer.audio, unit);
        }
    }
    transmuxer.video.close();
    transmuxer.audio.close();
});