Ruby version managers

[ysbaddaden]

There is a problem with having Prax written in Ruby while using a ruby version manager (like rbenv, rvm, chruby or ry).

Prax is a ruby process, running one version of ruby (say 2.0.0-p247) that spawns other ruby processes which sometimes require a specific ruby version or engine (say jruby-1.7.4). A per-project version can be selected uniformly with a .ruby-version file in your project folder.

One would think that version managers will take care of that, but they don't. They modify the PATH, so the correct gems are loaded for each ruby version, and they may set some environment variables to somehow for the selected ruby version —rbenv sets RUBY_VERSION.

So, version managers are getting in the way. How to fix that once and for all?

I initially fixed rbenv because this is the one I use. I recently got a patch for RVM that does RVM's job by loading the .ruby-version and forcing RVM to use that version, and one for chruby that does the same thing. We're only missing a patch for ry —others are deprecated in favor of chruby.

But I don't like this idea of doing the version manager's job. I'd like a fresh shell environment, cleaned from the selected ruby version, so that the version managers would do their job: select and run the ruby version that the user wants when I run ruby in a project with a .ruby-version file.

Is that possible? A fresh shell environment, coupled with the existing and sourceable ~/.praxconfig where any local configuration could happen.

[ysbaddaden]

See #23 and #25 for rbenv, #30 for RVM, and #35 #34 for chruby.

[ysbaddaden]

As @davekaro suggested, Pow uses .powenv for environment variables, and sources .powrc in your application directory, thus allowing to select a ruby version: http://pow.cx/manual.html#section_2.2

But a per project configuration looks quite cumbersome.

[ysbaddaden]

Reading the doc for Process.spawn, maybe the following could do the job, assuming that Racker will load either .praxrc in the app folder, then defaulting to ~/.praxconfig if .praxrc can't be found.

args = if gemfile?
  [' bundle', 'exec']
else
  ['ruby']
end << [racker_path, '--server', socket_path]

# are there any required environment vars to keep/set?
env = { 'PATH' => ENV['ORIG_PATH'] }

pid = Process.spawn(env, *args,
  :chdir => realpath,
  :out => [log_path, 'a'],
  :err => [:child, :out],
  :unsetenv_others => true,
  :close_others => true
)

[jneen]

Hey there, I'm the author of ry. What would you suggest as a way to make it more friendly to this sort of launching?

[mpapis]

here is dynamic code that loads proper ruby via RVM in Pow: https://rvm.io/integration/pow
for static variables use:

rvm env > .paxrc

[jneen]

nice! so for ry it'd be

ry setup $MY_RUBY > .praxrc

[ysbaddaden]

I updated the Ruby Version Manager with page with your snippets.