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rubybundlerjruby

bundler: specify ruby version based on platform

We're doing some A/B testing on MRI vs JRuby for a microservice we've written.

I need my server or any local developer to use a specified version of JRuby or MRI.

I've read through Bundler's docs and thought I understood the use of ruby engine's to be used like this:

platforms :jruby do
  ruby '1.9.3', engine: :jruby, engine_version: '1.7.19'
  gem 'bson'
end

platforms :ruby do
  ruby '2.2.0', engine: :ruby, engine_version: '2.2.0'
  gem 'bson_ext'
end

However if I do $which ruby I get: .rvm/rubies/jruby-1.7.19/bin/ruby and then run bundle install I get:

Your Ruby engine is jruby, but your Gemfile specified ruby

How can I use bundler with platforms to specify a ruby version specific to the platform the user/server is running?

Solution

  • as of current Bundler you can not do that, since :platforms only apply to gem declarations ... closest thing you can get is a "runtime" decision logic based on which Ruby loads the Gemfile : 

    if defined? JRUBY_VERSION
  ruby '1.9.3', engine: :jruby, engine_version: '1.7.19'
else
  ruby '2.2.0', engine: :ruby, engine_version: '2.2.0'
end

platforms :jruby do
  gem 'bson'
end

platforms :ruby do
  gem 'bson_ext'
end