add BuildEC2BlockDeviceMapping func to the BlockDevice type

builder/amazon/common/block_device.go

@@ -62,50 +62,57 @@ func (bds BlockDevices) BuildEC2BlockDeviceMappings() []*ec2.BlockDeviceMapping
 	var blockDevices []*ec2.BlockDeviceMapping
 
 	for _, blockDevice := range bds {
-		mapping := &ec2.BlockDeviceMapping{
-			DeviceName: aws.String(blockDevice.DeviceName),
-		}
+		blockDevices = append(blockDevices, blockDevice.BuildEC2BlockDeviceMapping())
+	}
+	return blockDevices
+}
+
+func (blockDevice BlockDevice) BuildEC2BlockDeviceMapping() *ec2.BlockDeviceMapping {
 
-		if blockDevice.NoDevice {
-			mapping.NoDevice = aws.String("")
-		} else if blockDevice.VirtualName != "" {
-			if strings.HasPrefix(blockDevice.VirtualName, "ephemeral") {
-				mapping.VirtualName = aws.String(blockDevice.VirtualName)
-			}
-		} else {
-			ebsBlockDevice := &ec2.EbsBlockDevice{
-				DeleteOnTermination: aws.Bool(blockDevice.DeleteOnTermination),
-			}
-
-			if blockDevice.VolumeType != "" {
-				ebsBlockDevice.VolumeType = aws.String(blockDevice.VolumeType)
-			}
-
-			if blockDevice.VolumeSize > 0 {
-				ebsBlockDevice.VolumeSize = aws.Int64(blockDevice.VolumeSize)
-			}
-
-			// IOPS is only valid for io1 type
-			if blockDevice.VolumeType == "io1" {
-				ebsBlockDevice.Iops = aws.Int64(blockDevice.IOPS)
-			}
-
-			// You cannot specify Encrypted if you specify a Snapshot ID
-			if blockDevice.SnapshotId != "" {
-				ebsBlockDevice.SnapshotId = aws.String(blockDevice.SnapshotId)
-			}
-			ebsBlockDevice.Encrypted = blockDevice.Encrypted
-
-			if blockDevice.KmsKeyId != "" {
-				ebsBlockDevice.KmsKeyId = aws.String(blockDevice.KmsKeyId)
-			}
-
-			mapping.Ebs = ebsBlockDevice
+	mapping := &ec2.BlockDeviceMapping{
+		DeviceName: aws.String(blockDevice.DeviceName),
+	}
+
+	if blockDevice.NoDevice {
+		mapping.NoDevice = aws.String("")
+		return mapping
+	} else if blockDevice.VirtualName != "" {
+		if strings.HasPrefix(blockDevice.VirtualName, "ephemeral") {
+			mapping.VirtualName = aws.String(blockDevice.VirtualName)
 		}
+		return mapping
+	}
 
-		blockDevices = append(blockDevices, mapping)
+	ebsBlockDevice := &ec2.EbsBlockDevice{
+		DeleteOnTermination: aws.Bool(blockDevice.DeleteOnTermination),
 	}
-	return blockDevices
+
+	if blockDevice.VolumeType != "" {
+		ebsBlockDevice.VolumeType = aws.String(blockDevice.VolumeType)
+	}
+
+	if blockDevice.VolumeSize > 0 {
+		ebsBlockDevice.VolumeSize = aws.Int64(blockDevice.VolumeSize)
+	}
+
+	// IOPS is only valid for io1 type
+	if blockDevice.VolumeType == "io1" {
+		ebsBlockDevice.Iops = aws.Int64(blockDevice.IOPS)
+	}
+
+	// You cannot specify Encrypted if you specify a Snapshot ID
+	if blockDevice.SnapshotId != "" {
+		ebsBlockDevice.SnapshotId = aws.String(blockDevice.SnapshotId)
+	}
+	ebsBlockDevice.Encrypted = blockDevice.Encrypted
+
+	if blockDevice.KmsKeyId != "" {
+		ebsBlockDevice.KmsKeyId = aws.String(blockDevice.KmsKeyId)
+	}
+
+	mapping.Ebs = ebsBlockDevice
+
+	return mapping
 }
 
 func (b *BlockDevice) Prepare(ctx *interpolate.Context) error {

builder/amazon/common/step_run_spot_instance_test.go

@@ -71,7 +71,7 @@ func tStateSpot() multistep.StateBag {
 	state.Put("ui", &packer.BasicUi{
 		Reader: new(bytes.Buffer),
 		Writer: new(bytes.Buffer),
-	}) 
+	})
 	state.Put("availability_zone", "us-east-1c")
 	state.Put("securityGroupIds", []string{"sg-0b8984db72f213dc3"})
 	state.Put("subnet_id", "subnet-077fde4e")