Check for puppet executable instead of gem

lib/librarian/puppet.rb

@@ -1,16 +1,33 @@
 require 'librarian'
 require 'fileutils'
+require 'open3'
+require 'open3_backport' if RUBY_VERSION < '1.9'
+
+status = nil
+out = nil
+error = nil
 
 begin
-  require 'puppet'
-rescue LoadError
+  Open3.popen3('puppet --version') {|stdin, stdout, stderr, wait_thr|
+    pid = wait_thr.pid # pid of the started process.
+    out = stdout.read
+    status = wait_thr.value # Process::Status object returned.
+  }
+rescue => e
+  error = e
+end
+
+if status.nil? or status.exitstatus != 0
   $stderr.puts <<-EOF
-Unable to load puppet. Either install it using native packages for your
-platform (eg .deb, .rpm, .dmg, etc) or as a gem (gem install puppet).
+Unable to load puppet. Please install it using native packages for your platform (eg .deb, .rpm, .dmg, etc).
+#{out.nil? or out.empty? ? "puppet --version returned #{status.exitstatus}" : out}
+#{error.message unless error.nil?}
 EOF
   exit 1
 end
 
+PUPPET_VERSION=out.split(' ').first.strip
+
 require 'librarian/puppet/extension'
 require 'librarian/puppet/version'
 

lib/librarian/puppet/source/forge.rb

@@ -107,7 +107,7 @@ def cache_version_unpacked!(version)
 
           def check_puppet_module_options
             min_version    = Gem::Version.create('2.7.13')
-            puppet_version = Gem::Version.create(`puppet --version`.split(' ').first.strip.gsub('-', '.'))
+            puppet_version = Gem::Version.create(PUPPET_VERSION.gsub('-', '.'))
 
             if puppet_version < min_version
               raise Error, "To get modules from the forge, we use the puppet faces module command. For this you need at least puppet version 2.7.13 and you have #{puppet_version}"

lib/librarian/puppet/source/git.rb

@@ -1,5 +1,6 @@
 require 'librarian/source/git'
 require 'librarian/puppet/source/local'
+require 'puppet'
 
 module Librarian
   module Source

librarian-puppet.gemspec

@@ -25,6 +25,7 @@ Gem::Specification.new do |s|
 
   s.add_dependency "librarian", ">=0.1.1"
   s.add_dependency "json"
+  s.add_dependency "open3_backport" if RUBY_VERSION < '1.9'
 
   s.add_development_dependency "rake"
   s.add_development_dependency "rspec"