Serverless-python-requirements: Docker progress

[doublemarked]

Just getting things set up, serverless package was hanging every time after the following line:

Serverless: Docker Image: lambci/lambda:build-python3.6

I poked around and determined that it's just taking a quite long time (~15min) to pull the docker images. That's fine, but it was quite unclear at first. It would help to have some details on the command line, either a progress meter or at least a warning.

[cgrimal]

See function ensureImage of the serverless-package-python-functions plugin.

They are using a docker images ... command to check if the image is already here or not, in order to display a warning message.

We could do the same I guess?

[dschep]

That's a good idea @cgrimal

[dfee]

I'm glad I saw this. I'm manually pulling the images so I can watch the progress bar. Would be helpful if STDOUT was passed through...