Add Dockerfile to support running in a container

[bkeepers]

Motivation

Between Licensee and Linguist, there are a lot of dependencies needed to get repolinter working to its fullest potential.

Proposed Changes

This PR adds a Dockerfile which builds both the Ruby and Node dependencies.

Usage:

$ docker run -it -v $PWD:/src -w /src bkeepers/repolinter
Target directory: /src
Ruleset: repolint.json
Linguist Axiom: Linguist not found in path, only running language-independent rules
✔ license-file-exists: found (LICENSE)
✔ readme-file-exists: found (README.md)
✔ contributing-file-exists: found (CONTRIBUTING.md)
✔ code-of-conduct-file-exists: found (CODE_OF_CONDUCT.md)
✔ readme-references-license: File README.md contains license
✔ binaries-not-present: Excluded file type doesn't exist (**/*.exe,**/*.dll,!node_modules/**)
✔ test-directory-exists: found (script/test)
✔ integrates-with-ci: found (.github/main.workflow)
✔ code-of-conduct-file-contains-email: File CODE_OF_CONDUCT.md contains email address
⚠ github-issue-template-exists: not found: (ISSUE_TEMPLATE*, .github/ISSUE_TEMPLATE*)
⚠ github-pull-request-template-exists: not found: (PULL_REQUEST_TEMPLATE*, .github/PULL_REQUEST_TEMPLATE*)
✔ license-detectable-by-licensee: Licensee identified the license for project: MIT

Test Plan

Ideally, you could build and run the tests via Docker on Travis CI.

TODO:

• Reduce the size of the built image
• Docs on using via docker

[craigez]

I was just thinking last week this would be useful, but hadn't had a chance to look into creating the dockerfile yet.

I tested this out and it works for me. Tested both by pulling the image from dockerhub or building it directly from the dockerfile. By no means am I a docker expert though.

One issue, I don't think it installs linguist in the expected way for repolinter.

Linguist Axiom: Linguist not found in path, only running language-independent rules

From a quick look at the code and running the shell on the docker image, maybe it is expecting it installed as "linguist" when it's installed by this docker file as "github-linguist".

[bkeepers]

From a quick look at the code and running the shell on the docker image, maybe it is expecting it installed as "linguist" when it's installed by this docker file as "github-linguist".

Looks like this was recently changed: github-linguist/linguist#4208

[bkeepers]

Fixed for linguist command in c13fe49. I'll open a separate PR for that since it needs fixed anyway.

[jwsloan]

The multi-stage build is a really slick way of dealing with needing ruby and node. I have a Dockerfile branch of this repo I haven't pushed yet, and I was using asdf to install both. Either way, I'm happy to see other folks see the value of having a Dockerfile in projects like this.

Going about adding Dockerfiles may be what I do for #hacktoberfest...

[bkeepers]

• Reduce the size of the built image

I got this down to 181MB. I think that's pretty good considering all the dependencies (ruby & node runtimes, git, gems & npm packages).

• Docs on using via docker

I added some docs in the Dockerfile. If you want to publish a docker image as part of the release process, it might also be worth adding it in the README.

[jwsloan]

This would probably be good to have in the top level README as well.

[trevmex]

I agree, though I think it is good enough to merge for now.

[jwsloan]

It might be cool to push an image from this out to DockerHub. Then anyone could docker pull todogroup/repolinter and then run it.

[bkeepers]

Looks like I got a little too aggressive with pruning dependencies:

$ docker run -it --entrypoint '' -v $PWD:/src -w /src bkeepers/repolinter github-linguist
Traceback (most recent call last):
	13: from /usr/local/bundle/bin/github-linguist:23:in `<main>'
	12: from /usr/local/bundle/bin/github-linguist:23:in `load'
	11: from /usr/local/bundle/gems/github-linguist-7.0.0/bin/github-linguist:5:in `<top (required)>'
	10: from /usr/local/lib/ruby/site_ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require'
	 9: from /usr/local/lib/ruby/site_ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require'
	 8: from /usr/local/bundle/gems/github-linguist-7.0.0/lib/linguist.rb:1:in `<top (required)>'
	 7: from /usr/local/lib/ruby/site_ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require'
	 6: from /usr/local/lib/ruby/site_ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require'
	 5: from /usr/local/bundle/gems/github-linguist-7.0.0/lib/linguist/blob_helper.rb:2:in `<top (required)>'
	 4: from /usr/local/lib/ruby/site_ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require'
	 3: from /usr/local/lib/ruby/site_ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require'
	 2: from /usr/local/bundle/gems/charlock_holmes-0.7.6/lib/charlock_holmes.rb:1:in `<top (required)>'
	 1: from /usr/local/lib/ruby/site_ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require'
/usr/local/lib/ruby/site_ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require': libicudata.so.57: cannot open shared object file: No such file or directory - /usr/local/bundle/gems/charlock_holmes-0.7.6/lib/charlock_holmes/charlock_holmes.so (LoadError)                                                                                                                                                    

[bkeepers]

The error ☝️ has been fixed.

[trevmex]

I like it! Just downloaded your fork and ran it. Works great!!!