add simple host aliases implementation and configuration options validation

lib/vagrant-hostmanager/config.rb

@@ -3,16 +3,45 @@ module VagrantPlugins
     class Config < Vagrant.plugin('2', :config)
       attr_accessor :auto_update
       attr_accessor :ignore_private_ip
+      attr_accessor :aliases
 
       def initialize
         @auto_update = UNSET_VALUE
         @ignore_private_ip = UNSET_VALUE
+        @aliases = Array.new 
       end
 
       def finalize!
         @auto_update = true if @auto_update == UNSET_VALUE
         @ignore_private_ip = false if @ignore_private_ip == UNSET_VALUE
       end
+
+      def validate(machine)
+        errors = Array.new
+
+        # check if auto_update option is defined in Vagrantfile
+        # and check if is either true or false accordingly
+        if (machine.config.hostmanager.auto_update &&
+            ![TrueClass, FalseClass].include?(auto_update.class))
+          errors << "A value for hostmanager.auto_update can be true or false."
+        end
+
+        # check if ignore_private_ip option is defined in Vagrantfile
+        # and check if is either true or false accordingly
+        if (machine.config.hostmanager.ignore_private_ip &&
+            ![TrueClass, FalseClass].include?(ignore_private_ip.class))
+          errors << "A value for hostmanager.ignore_private_ip can be true or false."
+        end
+
+        # check if aliases option is defined in Vagrantfile
+        # and check if is an Array accordingly
+        if (machine.config.hostmanager.aliases &&
+            !machine.config.hostmanager.aliases.kind_of?(Array))
+          errors << "A value for hostmanager.aliases must be an Array."
+        end
+        
+        { "HostManager configuration" => errors }
+      end
     end
   end
 end

lib/vagrant-hostmanager/hosts_file.rb

@@ -31,8 +31,9 @@ module VagrantPlugins
               machines << machine = env.machine(name, provider)
               host = machine.config.vm.hostname || name
               ip = get_ip_address.call(machine)
-              @logger.info "Adding /etc/hosts entry: #{ip} #{host}"
+              host_aliases = machine.config.hostmanager.aliases.join("\s").chomp
-              file << "#{ip}\t#{host}\n"
+              @logger.info "Adding /etc/hosts entry: #{ip} #{host} #{host_aliases}"
+              file << "#{ip}\t#{host}\s#{host_aliases}\n"
             end
           end
         end