How do I set correctly use RVM gemsets with the guard-shell plugin?

Question

I am trying to run a Ruby script via guard-shell. This script requires the redcarpet gem. When the script runs, I get a "cannot load such file" error, indicating that the gemset I'm expecting will be used is in fact not being used.

Here are some relevant parameters:

1. In the Guard app folder (where the Guardfile is):

   > ls -a
   .                .ruby-gemset   Gemfile     Guardfile
   ..      .ruby-version   Gemfile.lock    tmp1.txt
   > cat .ruby-*
   rails4
   2.1.2
   

2. The gem seems to be there:

   > gem which redcarpet
   /Users/sameer/.rvm/gems/ruby-2.1.2@rails4/extensions/x86_64-darwin-13/2.1.0-static/redcarpet-3.1.2/redcarpet.bundle
   

3. My Guardfile has watch(/(.*)/) {|m| `rvm list; rvm gemset list; gem which redcarpet` } which outputs:

   ERROR:  Can't find ruby library file or shared library redcarpet
   ERROR:  Can't find ruby library file or shared library redcarpet
   
   rvm rubies
   
   ruby-2.0.0-p353 [ x86_64 ]
   ruby-2.1.0-preview1 [ x86_64 ]
   ruby-2.1.1 [ x86_64 ]
   =* ruby-2.1.2 [ x86_64 ]
   
   # => - current
   # =* - current && default
   #  * - default
   
   gemsets for ruby-2.1.2 (found in /Users/sameer/.rvm/gems/ruby-2.1.2)
   (default)
   global
   => rails4
   

So what am I missing?

Answer 1

I get the same error you do, e.g.:

./my_prog.rb:1:in require': cannot load such file -- nokogiri (LoadError) from ./my_prog.rb:1:in'

But if I put the gem that the ruby program requires in the Gemfile, then the ruby program executes without error. If I comment out the line in the Gemfile, then once again the error occurs. The gem is installed either way, but if it's not listed in the Gemfile, then guard-shell produces that error.

My Guardfile:

guard :shell do
  watch /.*/ do |m|
    puts 'hello'
    `ruby ./my_prog.rb` 
  end
end

My Gemfile:

source 'https://rubygems.org'

group :development do
  gem 'guard', '2.6.1'
  gem 'guard-shell', '0.6.1'
  gem 'nokogiri', '1.6.2.1'
end

my_prog.rb:

require 'nokogiri'

puts 'goodbye'

Somewhat annoyingly, this is my output in the guard shell:

hellouard(main)> 
goodbye
[1] guard(main)>