Use RubyMine and Docker for development

Question

I'm trying to develop a Rails project without having to install Ruby and all server tools in my Windows local machine. I've created my Docker containers (Ruby and MySQL) and installed the Docker plugin on RubyMine 2016.1, however it seems not very practical for the development daily use, I mean the cycle develop, run, debug, just before deployment to test server.

Am I missing something to make this workflow possible? Or isn't Docker suggested for this step in the development process?

Answer 1

I don't develop under Windows, but here's how I handle this problem under Mac OS X. First off, my Rails project has a Guardfile set up that launches rails (guard-rails gem) and also manages running my tests whenever I make changes (guard-minitest gem). That's important to get fast turnaround time in development.

I launch docker daemonized, mounting a local directory into the docker image, with an exposed port 3000, running a never-ending command.

docker run -d -v {local Rails root}:/home/{railsapp} -p 3000:3000 {image id} tail -f /dev/null

I do this so I can connect to it with an arbitrary number of shells, to do any activities I can only do locally.

Ruby 2.2.5, Rails 5, and a bunch of Unix developer tools (heroku toolbelt, gcc et al.) are installed in the container. I don't set up a separate database container, as I use SQLite3 for development and pg for production (heroku). Eventually when my database use gets more complicated, I'll need to set that up, but until then it works very well to get off the ground.

I point RubyMine to the local rails root. With this, any changes are immediately reflected in the container. In another command line, I spin up ($ is host, # is container):

$ docker exec -it {container id} /bin/bash
# cd /home/{railsapp}
# bundle install
# bundle exec rake db:migrate
# bundle exec guard

• bundle install is only when I've made Gemfile changes or the first time.
• bundle exec rake db:migrate is only when I've made DB changes or the first time.

At this point I typically have a Rails instance that I can browse to at localhost:3000, and the RubyMine project is 'synchronized' to the Docker image. I then mostly make my changes in RubyMine, ignoring messages about not having various gems installed, etc., and focus on keeping my tests running cleanly as I develop.

For handling a console when I get exceptions, I need to add:

config.web_console.whitelisted_ips = ['172.16.0.0/12', '192.168.0.0/16']

to config/environments/development.rb in order for it to allow a web debug console when exceptions happen in development. (The 192.168/* might not be necessary in all cases, but some folks have run into problems that require it.)

I still can't debug using RubyMine, but I don't miss it anywhere near as much as I thought I would, especially with web consoles being available. Plus it allows me to run all the cool tools completely in the development environment, and not pollute my host system at all.

I spent a day or so trying to get the remote debugger to work, but the core problem appears to be that (the way ruby-debug works) you need to allow the debugging process (in the docker container) to 'reach out' to the host's port to connect and send debugging information. Unfortunately binding ports puts them 'in use', and so you can't create a 'listen only' connection from the host/RubyMine to a specific container port. I believe it's just a limitation of Docker at present, and a change in either the way Docker handles networking, or in the way the ruby-debug-ide command handles transmitting debugging information would help fix it.

The upshot of this approach is that it allows me very fast turnaround time for testing, and equally fast turnaround time for in-browser development. This is optimal for new app development, but might not work as well if you have a large, old, crufty, and less-tested codebase.

Most/all of these capabilities should be present in the Windows version of Docker, as well.