Can't deploy if you're using Rbenv locally

[equivalentideas]

Currently, with the version of Ruby (2.3.1) we're using, people (me) using rbenv can't deploy to production.

Here's how our capistrano config decides which ruby version to deploy with set :rvm_ruby_string, ENV['GEM_HOME'].gsub(/.*\//,"") https://github.com/openaustralia/planningalerts/blob/master/config/deploy.rb#L7

if stage != "development"
  require 'rvm/capistrano'
  set :rvm_ruby_string, ENV['GEM_HOME'].gsub(/.*\//,"")
end

The ENV['GEM_HOME'] is the path where RubyGems/bundler keeps your ruby gems. The gsub extracts what it expects to be the current ruby version out of that path. The problem is that why that seems to work for where RMV keeps it's ruby gems, it doesn't work for where rbenv keeps them.

Here's @henare’s description of the challenge:

work out how we get capistrano to understand we want to use 2.3.1
and to make it work on RVM machines and rbenv
and on the server 🙂
and no, hardcoding isn't the answer 🙂
however we do have the luxury of only using 1 Ruby version
so if that was specified in only one place that would be a very good thing
it's not bad right now. It's specified in .ruby-version
and I guess travis.yml
so if you can work out a solution that maintains that and works on rvm and rbenv that would be superfly

[equivalentideas]

One idea is trying what rvm-capistrano recommends:

set :rvm_ruby_string, :local

Reading the code 🤓 , it appears that if it sees :local it checks if you're using rbenv, and finds the details it wants. If you're not using rbenv, if calls back to ENV['GEM_HOME'].gsub(/.*\//,""). This is the same statement we have hardcoded in our deploy.rb. I wonder why? It looks like that's pretty old, so maybe it predates the :local option in rvm-capistrano.

I'm going to open a PR for this.

The other idea I had was pulling the value out of the .ruby-version file—but it seems much much preferable to integrate with rvm and do what it wants since that's what we're using in production.