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Question

I want to benchmark node.js systems.

Therefore I created a little programm which can encrypt and compress files (i want the app to be CPU intense). I thought it would make sense to repeate the encryption process multiple times. But whenever I dynamically pipe the stream, the program exits before finishing. Is there a way how I can wait till the stream finished?

My code looks like this:

            var readStream = fstream.Reader(sourcePath);
            var writeStream = fs.createWriteStream(sourcePath + '.tar.gz');

            var stream = readStream.on('error', function (e) {
                    handleError(e, errorMessageReadFile);
                })
                .pipe(tar.Pack()).on('error', function (e) {
                    handleError(e, errorMessageTarPack);
                });

            for (i = 0; i < algorithmCount; i++) {
                stream = stream.pipe(encryptStream).on('error', function (e) {
                    handleError(e, errorMessageEncrypt);
                });
                console.log("enc");
            }

            stream.pipe(gzip).on('error', function (e) {
                    handleError(e, errorMessageCompress);
                })
                .pipe(writeStream).on('error', function (e) {
                    handleError(e, errorMessageWriteFile);
                })
                .on('finish', function () {
                    console.log('done');
                });

Answer 1

This is likely a problem:

for (i = 0; i < algorithmCount; i++) {
    stream = stream.pipe(encryptStream);
}

Remember that .pipe returns the stream you're piping into . In other words: stream.pipe(encryptStream) returns encryptStream . The first iteration is fine: stream is initially the tar.Pack() stream, and so that gets piped into encryptStream . However, the second iteration will pipe stream which now equals encryptStream into itself .

You probably want to create a new intermediate encrypt stream for every iteration, eg something like:

for (i = 0; i < algorithmCount; i++) {
    stream = stream.pipe(createEncryptStream());
}