Use shell expansion when selecting which NODE_VERSION to build

[chorrell]

With this change we no longer need to update the .travis.yml file for
each minor update of a given Node.js image. Bash shell expansion will
determine the right version to build based on the available directories
(4.7, 6.9, 7.5 etc.)

That being said, a sanity check on this would be good :)

[LaurentGoderre]

Really? That would be great if it works!

[chorrell]

Yeah, it seems to work pretty well. I just pushed a small change to test-build.sh to call out which major.minor version is being tested.

[chorrell]

Also, to verify I did this simple test from within the repo:

$ versions=4*
$ versions=( "${versions[@]%/}" )
$ echo $versions
4.7

[chorrell]

Testing looks good and it does seem to be doing the right thing. I'd like to leave this open for a bit for review though :)

[LaurentGoderre]

@chorrell is there any reason where we would have to support two separate minor versions for a major version? If we did, it still wouldn't block this, we would just have to expand just that version

[chorrell]

@LaurentGoderre I was pondering that scenario too and I think it's very unlikely we would do that.

[tianon]

Another solution would be to simply rename the folders to be the minimum supported specificity (see https://github.com/docker-library/elasticsearch for an example -- it has 1.7, 2.4, and 5 as folders).

[chorrell]

I'd be fine with that too :)

If we go the dir renaming route, I guess we'd need to generate a new library file since the values of Directory: would change. And we'd need to update the logic in generate-stackbrew-library.sh that generates the values for Tags:

[LaurentGoderre]

@tianon How would the Travis matrix be updated though?

[tianon]

@LaurentGoderre the Travis matrix would reference the folders -- https://github.com/docker-library/elasticsearch/blob/ffaaf3283e47dcb732e90288a58757b87a8439a7/.travis.yml#L4-L10

env:
  - VERSION=5 VARIANT=
  - VERSION=5 VARIANT=alpine
  - VERSION=2.4 VARIANT=
  - VERSION=2.4 VARIANT=alpine
  - VERSION=1.7 VARIANT=
  - VERSION=1.7 VARIANT=alpine

[LaurentGoderre]

I think I would prefer to keep it simple and only expand the ones that need it

env:
    matrix :
        NODE_VERSION: '4.*'
        NODE_VERSION: '6.1'
        NODE_VERSION: '6.2'
        NODE_VERSION: '7.*'

[chorrell]

Is this something we can merge for now and then consider folder renaming in a separate issue/PR?

[nschonni]

@chorrell looks like the first commits were done with an email not associated with your GH account, might want to add it in your profile

[chorrell]

The email address was removed from my profile because I don't work there anymore.

[SimenB]

@chorrell can you resolve the conflict?

[SimenB]

Hah, I could do it in the web gui 😄

[chorrell]

Nice! Are we good to merge this now?

cc @nodejs/docker

[chorrell]

Huh, why did this fail?

https://travis-ci.org/nodejs/docker-node/jobs/257409744

[SimenB]

I was gonna merge when I got a green CI. I'm not because of the toc being different... (Could you fix that? I'm on mobile currently.) But if 4, 6 and 8 builds successfully, I'll merge (if no one beats me to it)

[SimenB]

I broke it when merging #328

[chorrell]

Ah, ok.