Fixing transient AWS errors during EBS builds

Relates to hashicorp#1539

AWS is eventually consistent and instance can be not visibile for
some time after creation. This fix eliminates describe-instances
call before going to the proper wait loop

builder/amazon/common/state.go

@@ -63,9 +63,9 @@ func AMIStateRefreshFunc(conn *ec2.EC2, imageId string) StateRefreshFunc {
 
 // InstanceStateRefreshFunc returns a StateRefreshFunc that is used to watch
 // an EC2 instance.
-func InstanceStateRefreshFunc(conn *ec2.EC2, i *ec2.Instance) StateRefreshFunc {
+func InstanceStateRefreshFunc(conn *ec2.EC2, instanceId string) StateRefreshFunc {
 	return func() (interface{}, string, error) {
-		resp, err := conn.Instances([]string{i.InstanceId}, ec2.NewFilter())
+		resp, err := conn.Instances([]string{instanceId}, ec2.NewFilter())
 		if err != nil {
 			if ec2err, ok := err.(*ec2.Error); ok && ec2err.Code == "InvalidInstanceID.NotFound" {
 				// Set this to nil as if we didn't find anything.
@@ -85,7 +85,7 @@ func InstanceStateRefreshFunc(conn *ec2.EC2, i *ec2.Instance) StateRefreshFunc {
 			return nil, "", nil
 		}
 
-		i = &resp.Reservations[0].Instances[0]
+		i := &resp.Reservations[0].Instances[0]
 		return i, i.State.Name, nil
 	}
 }

builder/amazon/common/step_run_source_instance.go

@@ -195,21 +195,13 @@ func (s *StepRunSourceInstance) Run(state multistep.StateBag) multistep.StepActi
 		instanceId = spotResp.SpotRequestResults[0].InstanceId
 	}
 
-	instanceResp, err := ec2conn.Instances([]string{instanceId}, nil)
-	if err != nil {
-		err := fmt.Errorf("Error finding source instance (%s): %s", instanceId, err)
-		state.Put("error", err)
-		ui.Error(err.Error())
-		return multistep.ActionHalt
-	}
-	s.instance = &instanceResp.Reservations[0].Instances[0]
-	ui.Message(fmt.Sprintf("Instance ID: %s", s.instance.InstanceId))
+	ui.Message(fmt.Sprintf("Instance ID: %s", instanceId))
 
-	ui.Say(fmt.Sprintf("Waiting for instance (%s) to become ready...", s.instance.InstanceId))
+	ui.Say(fmt.Sprintf("Waiting for instance (%v) to become ready...", instanceId))
 	stateChange := StateChangeConf{
 		Pending:   []string{"pending"},
 		Target:    "running",
-		Refresh:   InstanceStateRefreshFunc(ec2conn, s.instance),
+		Refresh:   InstanceStateRefreshFunc(ec2conn, instanceId),
 		StepState: state,
 	}
 	latestInstance, err := WaitForState(&stateChange)
@@ -285,7 +277,7 @@ func (s *StepRunSourceInstance) Cleanup(state multistep.StateBag) {
 		}
 		stateChange := StateChangeConf{
 			Pending: []string{"pending", "running", "shutting-down", "stopped", "stopping"},
-			Refresh: InstanceStateRefreshFunc(ec2conn, s.instance),
+			Refresh: InstanceStateRefreshFunc(ec2conn, s.instance.InstanceId),
 			Target:  "terminated",
 		}
 

builder/amazon/ebs/step_create_ami.go

@@ -87,7 +87,7 @@ func (s *stepCreateAMI) Cleanup(state multistep.StateBag) {
 		ui.Error(fmt.Sprintf("Error deregistering AMI, may still be around: %s", err))
 		return
 	} else if resp.Return == false {
-		ui.Error(fmt.Sprintf("Error deregistering AMI, may still be around: %t", resp.Return))
+		ui.Error(fmt.Sprintf("Error deregistering AMI, may still be around"))
 		return
 	}
 }

builder/amazon/ebs/step_stop_instance.go

@@ -37,7 +37,7 @@ func (s *stepStopInstance) Run(state multistep.StateBag) multistep.StepAction {
 	stateChange := awscommon.StateChangeConf{
 		Pending:   []string{"running", "stopping"},
 		Target:    "stopped",
-		Refresh:   awscommon.InstanceStateRefreshFunc(ec2conn, instance),
+		Refresh:   awscommon.InstanceStateRefreshFunc(ec2conn, instance.InstanceId),
 		StepState: state,
 	}
 	_, err = awscommon.WaitForState(&stateChange)