As discussed..

modules/ruby/manifests/init.pp

 # == Class: ruby
 #
 # Perform a custom Ruby installation based on the ruby-install script,
 # using /usr/local as installation prefix.
 #
 # === Parameters:
 #
 # [*version*]
-#   The Ruby version to clone and build.
+#   The Ruby version to build and install.
+#
+# [*logoutput*]
+#   Whether and when to log the output of Exec resources; see
+#   https://docs.puppetlabs.com/references/latest/type.html#exec-attribute-logoutput
 #
 # === Examples:
 #
 #   class {'ruby':
 #     version => '2.2.0',
+#     logoutput => true,
 #   }
 #
 class ruby(
   $version = '2.1.5',
+  $logoutput = 'on_failure',
 ) {
 
-  $ruby_install_source_url = 'https://github.com/postmodern/ruby-install.git'
-  $ruby_install_source_dir = "/root/ruby-install"
-
-  Package {
-    ensure => 'installed',
-  }
+  $install_src_url = 'https://github.com/postmodern/ruby-install.git'
+  $install_src_dir = '/root/ruby-install'
+  $install_command = "$install_src_dir/bin/ruby-install"
 
   Exec {
     logoutput => true,
     path => '/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin',
   }
 
   if !defined(Package['git']) {
-    package {'git': }
+
+    package {'git':
+      ensure => 'installed',
+    }
   }
 
   exec {'ruby-clone-ruby-install':
-    command => shellquote('git', 'clone', $ruby_install_source_url, $ruby_install_source_dir),
-    creates => $ruby_install_source_dir,
+    command => shellquote('git', 'clone', $install_src_url, $install_src_dir),
+    creates => $install_src_dir,
+    logoutput => $logoutput,
+    require => Package['git'],
   }
   ->
   exec {'ruby-execute-ruby-install':
-    command => shellquote("$ruby_install_source_dir/bin/ruby-install", '--system', 'ruby', $ruby_version),
-    creates => "/usr/local/bin/ruby",
+    command => shellquote($install_command, '--system', 'ruby', $version),
+    creates => '/usr/local/bin/ruby',
+    logoutput => $logoutput,
   }
-
-  Exec['ruby-clone-ruby-install'] <- Package['git']
 }