Docker image files are read synchronously

[eslap]

When loading a saved docker image from a file, the readFile operation is done synchronously, thus blocking Node.js event loop for the duration of the operation. A docker image export file can be quite big, which would result in other tasks to starve, since they would not get any CPU. An asynchonous file read approach should be preferred.

Is there a reason for reading these file synchronously?

The related snippet:

if (options.file) {
    if (typeof options.file === 'string') {
      data = fs.readFileSync(path.resolve(options.file));
    } else {
      data = options.file;
    }
    optionsf.headers['Content-Type'] = 'application/tar';
  } else if (opts && options.method === 'POST') {
    data = JSON.stringify(opts._body || opts);
    optionsf.headers['Content-Type'] = 'application/json';
}