python - Bundling data files with PyInstaller (--onefile)

Question

I'm trying to build a one-file EXE with PyInstaller which is to include an image and an icon. I cannot for the life of me get it to work with --onefile.

If I do --onedir it works all works very well. When I use --onefile, it can't find the referenced additional files (when running the compiled EXE). It finds the DLLs and everything else fine, just not the two images.

I've looked in the temp-dir generated when running the EXE (Temp\_MEI95642 for example) and the files are indeed in there. When I drop the EXE in that temp-directory it finds them. Very perplexing.

This is what I've added to the .spec file

a.datas += [('images/icon.ico', 'D:\[workspace]\App\src\images\icon.ico',  'DATA'),
('images/loaderani.gif','D:\[workspace]\App\src\images\loaderani.gif','DATA')]     

I should add that I have tried not putting them in subfolders as well, didn't make a difference.

Edit: Marked newer answer as correct due to PyInstaller update.

Answer 1

Newer versions of PyInstaller do not set the env variable anymore, so Shish's excellent answer will not work. Now the path gets set as sys._MEIPASS:

def resource_path(relative_path):
    """ Get absolute path to resource, works for dev and for PyInstaller """
    try:
        # PyInstaller creates a temp folder and stores path in _MEIPASS
        base_path = sys._MEIPASS
    except Exception:
        base_path = os.path.abspath(".")

    return os.path.join(base_path, relative_path)