Add R support

[BirgerK]

See more in #15

[dylanmei]

I will fire this up shortly. Will you also remove this line from your PR? It removes Zeppelin's SparkR notebook/tutorial which I think we'd like to make available along with these changes.

https://github.com/dylanmei/docker-zeppelin/blob/master/Dockerfile#L53

[dylanmei]

My first attempt to build this failed.

[ERROR] Could not find the selected project in the reactor: r @ 
Could not find the selected project in the reactor: r -> [Help 1]

I notice there is no "r" module in Zeppelin's top-level pom.xml. There are however -Pr and -Psparkr, which is confusing. It seems like the direction they are going with R support is not fully worked out.

[BirgerK]

I will remove the line, yes.

And that's confusing. But how about just using their maven-profiles? I guess they include everything Zeppelin needs. Maybe this image is even missing something we don't know?

Did you compare the image-size by using maven-profiles and your way?

[dylanmei]

Using the -Pr profile brings the image from 1.69Gb to 2.47Gb. But just adding -Pr didn't make the %r interpreter available to me yet.

[BirgerK]

The %r-interpreter is "hidden" in the spark-interpreter. Beneath to spark you see a list of %-entries. On my installation %r appears there.

[dylanmei]

I must be missing something. 😕

I needed to add -Pr to get it to even build. But now that it's built I don't see the hidden %r interpreter in the spark-interpreter.

[BirgerK]

Seems like they're doing something in the maven-profiles.

EDIT: But it's your decision if you want the full R-support in your image. I understand if it's a decision of size for you. I want it, so i would just do a fork of your image. That's no problem! :)