docker: enable debugging with byebug and friends

[mcritchlow]

Fixes #issuenumber

Local Checklist

• QA-ed locally?
• Configuration updated (if needed)?
• Documentation updated (if needed)?

What does this PR do?

Adds support and documentation for use debuggers like byebug with the docker/compose development environment

Why are we doing this? Any context of related work?

This is still new territory for us, and I ran across this issue working on a different project last week. So I thought I would document and add the solution that I found here.

Where should a reviewer start?

See docker/README.md for how this would be used in practice

Manual testing steps?

• Run a fresh build using the docker/dev/docker-compose.yml file.
• Add a byebug statement somewhere. Controller, wherever.
• Run the app and get it to trigger the breakpoint
• Follow the instructions for using docker attach <container> and try interacting with byebug

@ucsdlib/developers and @orangewolf - please review

[VivianChu]

👍

[hweng]

👍

[lsitu]

@mcritchlow It looks good with docker. Thanks. However, we haven't included gem byebug in damspas develop and test. when interacting with it I see error like Error wrapping anonymous request: undefined local variable or method `byebug' for #<CatalogController:0x00005654b0c1b398>.

[mcritchlow]

@lsitu - that's a good point. this is more on the assumption that one might use byebug, or another debugger that requires a terminal to interact with, like pry. So the error you're seeing makes sense, byebug isn't actually in our Gemfile in the test/dev group. I can add it as part of this PR if folks would like, but I was admittedly writing this as something that could support it. Thoughts?

[lsitu]

@mcritchlow I am fine to have byebug gem added to test/dev group to make it works. But I think we can just update the documentation for it.

[mcritchlow]

@lsitu - Ok sounds good. I'll add it to the Gemfile in a separate commit. Thanks for the feedback!

[coveralls]

Coverage remained the same at 66.682% when pulling da0ebcb on feature/support-docker-debugging into 2fe103f on master.

[lsitu]

👍