builder/amazon/all: launched instances have a name [GH-642]

CHANGELOG.md

@@ -23,6 +23,8 @@ IMPROVEMENTS:
 * core: Plugins communicate over a single TCP connection per plugin now,
   instead of sometimes dozens. Performance around plugin communication
   dramatically increased.
+* builder/amazon/all: Launched EC2 instances now have a name of
+  "Packer Builder" so that they are easily recognizable. [GH-642]
 * builder/amazon/all: Copying AMIs to multiple regions now happens
   in parallel. [GH-495]
 * builder/qemu: Floppy files are supported. [GH-686]

builder/amazon/common/step_run_source_instance.go

@@ -6,7 +6,6 @@ import (
 	"github.com/mitchellh/multistep"
 	"github.com/mitchellh/packer/packer"
 	"io/ioutil"
-	"log"
 )
 
 type StepRunSourceInstance struct {
@@ -91,7 +90,14 @@ func (s *StepRunSourceInstance) Run(state multistep.StateBag) multistep.StepActi
 	}
 
 	s.instance = &runResp.Instances[0]
-	log.Printf("instance id: %s", s.instance.InstanceId)
+	ui.Message(fmt.Sprintf("Instance ID: %s", s.instance.InstanceId))
+
+	_, err = ec2conn.CreateTags(
+		[]string{s.instance.InstanceId}, []ec2.Tag{{"Name", "Packer Builder"}})
+	if err != nil {
+		ui.Message(
+			fmt.Sprintf("Failed to tag a Name on the builder instance: %s", err))
+	}
 
 	ui.Say(fmt.Sprintf("Waiting for instance (%s) to become ready...", s.instance.InstanceId))
 	stateChange := StateChangeConf{