[vsphere|compute] Implemented idiomatic interface creation.

lib/fog/vsphere/models/compute/interface.rb

@@ -4,6 +4,8 @@ module Fog
 
       class Interface < Fog::Model
 
+        SAVE_MUTEX = Mutex.new
+
         identity :mac
         alias :id :mac
 
@@ -44,6 +46,34 @@ module Fog
           service.destroy_vm_interface(server_id, :key => key, :type => type)
         end
 
+        def save
+          raise Fog::Errors::Error.new('Resaving an existing object may create a duplicate') if persisted?
+          requires :server_id, :type, :network
+
+          # Our approach of finding the newly created interface is rough.  We assume that the :key value always increments
+          # and thus the highest :key value must correspond to the created interface.  Since this has an inherent race
+          # condition we need to gate the saves.
+          SAVE_MUTEX.synchronize do
+            data = service.add_vm_interface(server_id, attributes)
+
+            if data['task_state'] == 'success'
+              # We have to query vSphere to get the interface attributes since the task handle doesn't include that info.
+              created = server.interfaces.all.sort_by(&:key).last
+
+              self.mac = created.mac
+              self.name = created.name
+              self.status = created.status
+              self.summary = created.summary
+              self.key = created.key
+              self.virtualswitch = created.virtualswitch
+
+              true
+            else
+              false
+            end
+          end
+        end
+
         private
 
         def defaults

lib/fog/vsphere/models/compute/interfaces.rb

@@ -48,7 +48,7 @@ module Fog
 
         def new(attributes = {})
           if server
-            super({ :server => server }.merge(attributes))
+            super({ :server_id => server.id  }.merge(attributes))
           else
             super
           end

lib/fog/vsphere/requests/compute/modify_vm_interface.rb

@@ -6,7 +6,7 @@ module Fog
         def add_vm_interface(vmid, options = {})
           raise ArgumentError, "instance id is a required parameter" unless vmid
 
-          interface = get_interface_from_options(vmid, options)
+          interface = get_interface_from_options(vmid, options.merge(:server_id => vmid))
           vm_reconfig_hardware('instance_uuid' => vmid, 'hardware_spec' => {'deviceChange'=>[create_interface(interface)]})
         end