Dockerfile best practices need to be applied

[mcapuccini]

Docker file install needs to be splitted in multiple commands. As it is now it is hard to read. https://github.com/kubenow/KubeNow/blob/master/Dockerfile#L26-L61

[andersla]

Yes but otherwise it creates more layers and get substantially larger... In the future Travis might support the new (currently experimental) command docker --squash

[mcapuccini]

Docker squash is now in Travis: https://github.com/travis-ci/travis-ci/issues/7380

[andersla]

Unfortunately it is still part of the "experimental" features not enabled on travis - I already did try to enable it with env-vars but never got it to work.

[mcapuccini]

Is there any thread we can follow, so we kwon when it will become available?

[bebehei]

Well, if you want to have your stuff readable and in one RUN, simply follow the dockerfile best practices. There is no need to split it and squash it.

RUN true \
 && command \
 && apt install -y \
      aIndented \
      bAnd \
      cSORTED \
      dPackage \
      eList \
 && command \
 && true

• Group (read: indent) the commands correct.
• Pack the arguments into a new line (and if the arguments are a set, sort it!)
• I usually add true as the first and last command. This allows me to insert commands at the beginning/end without touching the previous first/last command and not polluting the git history

---

The stuff with the

`# this is a comment`

is genius!

[bebehei]

I'm submitting a PR. Give me some time pls.

[mcapuccini]

That's a good remark 🙂

[bebehei]

So, I also reviewed this part of the dockerfile (But I'm not touching these with the PR):

• Also, there should be an export DEBIAN_FRONTEND=noninteractive in every RUN statement involving apt. (Do not export it in an ENV).
• The multiple ENVs should also be grouped together.
• If you install apt-transport-https, I think you should also add the repository with https instead of http.
• As you're downloading from https, it might be also good to make sure, that ca-certificates package is installed and up to date.

[bebehei]

@mcapuccini Thanks for merging #312. But KIM the other points, I also have noted in my previous comment here.

[mcapuccini]

Yep, reopening the issue and renaming it 🙂