Improve Dockerfile

[glogiotatidis]

Hey folks,

This is a much improved dockerfile I thought to prepare for you with some docker best-practices. Here it goes:

• Improve docker caching: Move commands that will not change with code changes on the top, like WORKDIR, apt-get install etc. This way when only your code changes these docker layers will not get invalidated.
• Start with a slimmer image, less download, more profit.
• Copy requirements and pip install before code to improve caching even further.
• Run apt-get update and apt-get installs in the same line, otherwise you will eventually end up with docker images that cannot get build because the apt-get update will be cached and pointing to packages that no longer exist. See for more caching and “apt-get update” moby/moby#3313
• ADD is a complicated command with lots of magic (url downloading, auto tarball extraction, etc). Try to use COPY instead and limit ADD use to the absolute necessary.

More can be done like create a user and run based on that user which will help with file permissions on the host too.

Enjoy!

[comzeradd]

Looks good to me. I'll let @johngian review it further since he's done the docker implementation here.