builder/amazonebs: Better checking for states

builder/amazonebs/instance.go

@@ -7,12 +7,24 @@ import (
 	"time"
 )
 
-func waitForState(ec2conn *ec2.EC2, originalInstance *ec2.Instance, target string) (i *ec2.Instance, err error) {
+func waitForState(ec2conn *ec2.EC2, originalInstance *ec2.Instance, pending []string, target string) (i *ec2.Instance, err error) {
 	log.Printf("Waiting for instance state to become: %s", target)
 
 	i = originalInstance
-	original := i.State.Name
+	for i.State.Name != target {
-	for i.State.Name == original {
+		found := false
+		for _, allowed := range pending {
+			if i.State.Name == allowed {
+				found = true
+				break
+			}
+		}
+
+		if !found {
+			fmt.Errorf("unexpected state '%s', wanted target '%s'", i.State.Name, target)
+			return
+		}
+
 		var resp *ec2.InstancesResp
 		resp, err = ec2conn.Instances([]string{i.InstanceId}, ec2.NewFilter())
 		if err != nil {
@@ -20,14 +32,8 @@ func waitForState(ec2conn *ec2.EC2, originalInstance *ec2.Instance, target strin
 		}
 
 		i = &resp.Reservations[0].Instances[0]
-
 		time.Sleep(2 * time.Second)
 	}
 
-	if i.State.Name != target {
-		err = fmt.Errorf("unexpected target state '%s', wanted '%s'", i.State.Name, target)
-		return
-	}
-
 	return
 }

builder/amazonebs/step_run_source_instance.go

@@ -36,7 +36,7 @@ func (s *stepRunSourceInstance) Run(state map[string]interface{}) multistep.Step
 	log.Printf("instance id: %s", s.instance.InstanceId)
 
 	ui.Say("Waiting for instance to become ready...")
-	s.instance, err = waitForState(ec2conn, s.instance, "running")
+	s.instance, err = waitForState(ec2conn, s.instance, []string{"pending"}, "running")
 	if err != nil {
 		ui.Error(err.Error())
 		return multistep.ActionHalt

builder/amazonebs/step_stop_instance.go

@@ -25,7 +25,7 @@ func (s *stepStopInstance) Run(state map[string]interface{}) multistep.StepActio
 	// TODO(mitchellh): Handle diff source states, i.e. this force state sucks
 	ui.Say("Waiting for the instance to stop...")
 	instance.State.Name = "stopping"
-	instance, err = waitForState(ec2conn, instance, "stopped")
+	instance, err = waitForState(ec2conn, instance, []string{"running", "stopping"}, "stopped")
 	if err != nil {
 		ui.Error(err.Error())
 		return multistep.ActionHalt