Add mongodb_is_master fact, which is either true or false based on db.isMaster(), or 'not_installed' if mongo isn't installed

Author: fatmcgav

lib/facter/is_master.rb

@@ -0,0 +1,12 @@
+require 'json';
+
+Facter.add('mongodb_is_master') do
+  setcode do
+    if Facter::Core::Execution.which('mongo') 
+      mongo_output = Facter::Core::Execution.exec('mongo --quiet --eval "load(\'/root/.mongorc.js\'); printjson(db.isMaster())"')
+      JSON.parse(mongo_output.gsub(/ISODate\((.+?)\)/, '\1 '))['ismaster'] ||= false
+    else 
+      'not_installed'
+    end
+  end
+end