Allow to define custom IP resolver

lib/vagrant-hostmanager/config.rb

@@ -5,6 +5,7 @@ module VagrantPlugins
       attr_accessor :ignore_private_ip
       attr_accessor :aliases
       attr_accessor :include_offline
+      attr_accessor :ip_resolver
 
       alias_method :enabled?, :enabled
       alias_method :include_offline?, :include_offline
@@ -14,6 +15,7 @@ module VagrantPlugins
         @ignore_private_ip = UNSET_VALUE
         @aliases = Array.new
         @include_offline = false
+        @ip_resolver = nil
       end
 
       def finalize!
@@ -36,7 +38,7 @@ module VagrantPlugins
         end
 
         # check if aliases option is an Array
-        if  !machine.config.hostmanager.aliases.kind_of?(Array) and
+        if  !machine.config.hostmanager.aliases.kind_of?(Array) &&
             !machine.config.hostmanager.aliases.kind_of?(String)
           errors << I18n.t('vagrant_hostmanager.config.not_an_array_or_string', {
             :config_key => 'hostmanager.aliases',
@@ -44,6 +46,14 @@ module VagrantPlugins
           })
         end
 
+        if !machine.config.hostmanager.ip_resolver.nil? &&
+           !machine.config.hostmanager.ip_resolver.kind_of?(Proc)
+          errors << I18n.t('vagrant_hostmanager.config.not_a_proc', {
+            :config_key => 'hostmanager.ip_resolver',
+            :is_class   => ip_resolver.class.to_s,
+          })
+        end
+
         errors.compact!
         { "HostManager configuration" => errors }
       end

lib/vagrant-hostmanager/hosts_file.rb

@@ -7,17 +7,23 @@ module VagrantPlugins
       def generate(env, provider)
         machines = []
 
+
         # define a lambda for looking up a machine's ip address
         get_ip_address = lambda do |machine|
-          ip = nil
-          if machine.config.hostmanager.ignore_private_ip != true
-            machine.config.vm.networks.each do |network|
-              key, options = network[0], network[1]
-              ip = options[:ip] if key == :private_network
-              next if ip
+          custom_ip_resolver = machine.config.hostmanager.ip_resolver
+          if custom_ip_resolver
+            custom_ip_resolver.call(machine)
+          else
+            ip = nil
+            if machine.config.hostmanager.ignore_private_ip != true
+              machine.config.vm.networks.each do |network|
+                key, options = network[0], network[1]
+                ip = options[:ip] if key == :private_network
+                next if ip
+              end
             end
+            ip || (machine.ssh_info ? machine.ssh_info[:host] : nil)
           end
-          ip || (machine.ssh_info ? machine.ssh_info[:host] : nil)
         end
 
         # create the temporary hosts file

locales/en.yml

@@ -7,3 +7,4 @@ en:
     config:
       not_a_bool: "A value for %{config_key} can only be true or false, not type '%{value}'"
       not_an_array_or_string: "A value for %{config_key} must be an Array or String, not type '%{is_class}'"
+      not_a_proc: "A value for %{config_key} must be a Proc, not type '%{is_class}'"