Support shared code between multiple models

[bfirsh]

Suppose you have a directory structure like this:

model1/
  cog.yaml
model2/
  cog.yaml
shared/
  somelib.py

It would be neat if there was an easy way to read shared from the models. Open to ideas.

The Docker way of doing this is to build from the parent directory and then specify the file with -f, but this is not ideal because then all the models have to support the working directory containing the parent directory, and you have to specify -f all the time to make it work.

[bfirsh]

@michaeldwan had a good idea: cog.yaml could specify its own build context directory, which could be a parent directory.

Something like this perhaps?

build:
  context: ../
predict: model1/predict.py

It's kinda weird that predict isn't relative to the current directory. Hmm.

[SaboniAmine]

I guess having a build context specification could solve most of the relative import issues.