Update all Dockerfiles to use multi-stage builds

[taharah]

Signed-off-by: Trevor Wood [email protected]

Fixes issue #367

Proposed Changes

• Updates all Dockerfiles to use multi-stage builds
• Optimized builds while preserving backwards compatibility

[yoshi-1224]

@taharah This is a very minor thing, but could you update the message on build.sh for helm binding such that in cases where go is not available and go build did not run, rather than

[WARN] go is not available on this system -- skipping Helm binding build!
libtemplate.so built successfully

we output something like

[WARN] go is not available on this system -- skipping Helm binding build!
libtemplate.so built successfully or already exists

Just so that we or other developers don't get confused? Sorry I didn't do this in the previous PR.

[uberspot]

Let's do another pass here and try to simplify these Docker images so maintenance is easier. :)
The initial PR looks good. 👍

[uberspot]

All looks good now, thank you for fixing the comments. :)
One minor missing dependency fails the travis build still

generating ./helm_binding.py
(already up-to-date)
chmod: cannot access './scripts/pyinstaller.sh': No such file or directory

Which I assume is because we also have to COPY ./scripts/ ./scripts/ in the dockerfiles?

[uberspot]

LGTM! Would be good to get another approval from someone and then merge.
@ramaro or @yoshi-1224 ? :)

[uberspot]

Btw, average build time dropped from ~18-19 minutes to 12-13. 👍
https://travis-ci.org/deepmind/kapitan/builds/
Also the resulting image is significantly smaller:

$ docker images | grep kapitan
deepmind/kapitan                        0.24.1                         b5a2f28f3dff        8 minutes ago       332MB
....
deepmind/kapitan                        0.24.0                         a955dc230ec1        2 weeks ago         857MB

Nice work! 👍