Can you run ExifToolHelpers in multiple threads?

[kwilinsi]

I have a script that processes thousands of images with multiple worker threads. Each worker does a few things, including extract metadata with PyExifTool.

It's convenient for each worker/thread to create its own exiftool.ExifToolHelper instance. Is this safe?

It seems to work most of the time, but every once in a while I think the program is hanging on ExifToolHelper.run() (it's inconsistent and difficult to test exactly). I'm suspicious that multithreading may be the problem.

If this isn't supported, then I'll need to share one ExifToolHelper between threads (not processes). Is it thread safe, or is a lock necessary?