refreshing imports

[seandepagnier]

I have an environment (tinycore linux) where as the system boots, python modules get loaded. The program needs to start up quickly, and it takes a while to load some modules like scipy.

In python2, this was not a problem, I could:

try:
    import scipy
except:
    return

and try again later.

In python3, this does not work. I have to restart the process, it always fails even long after the module is available if it was not available when python3 started.

I tried
import importlib
importlib.invalidate_caches()

but this does not work either, it doesn't solve the problem.

I know it's possible to use multiprocessing and communicate over pipes to get around this issue but it's really making the code complicated and less efficient.

So, how do I get the interpreter to rescan the available modules after it's started since invalidate_caches doesn't do what it claims to?