Use file type definition for disks

Using file type definition for disks allows virt-aa-helper to identify
the backing file correctly from the generated XML and add the necessary
permissions to permit qemu to be able to access the storage disk
provided it is located within a storage pool.

Ensure that reading of existing tfstate using pool/volume definition
remains working for upgrade compatibility by checking first if `File` is
a non-zero string.

Fixes #126

2 files changed, 24 insertions, 34 deletions

diff --git a/libvirt/disk_def.go b/libvirt/disk_def.go
index 737364c3..a659cdb3 100644
--- a/libvirt/disk_def.go
+++ b/libvirt/disk_def.go
@@ -17,8 +17,10 @@ type defDisk struct {
 		Type string `xml:"type,attr"`
 	} `xml:"format"`
 	Source struct {
-		Pool   string `xml:"pool,attr"`
-		Volume string `xml:"volume,attr"`
+		File   string `xml:"file,attr,omitempty"`
+		// retain Pool/Volume for compatibility with existing tfstate
+		Pool   string `xml:"pool,attr,omitempty"`
+		Volume string `xml:"volume,attr,omitempty"`
 	} `xml:"source"`
 	Target struct {
 		Dev string `xml:"dev,attr"`
@@ -32,7 +34,7 @@ type defDisk struct {
 
 func newDefDisk() defDisk {
 	disk := defDisk{}
-	disk.Type = "volume"
+	disk.Type = "file"
 	disk.Device = "disk"
 	disk.Format.Type = "qcow2"
 	disk.Target.Bus = "virtio"
@@ -45,7 +47,7 @@ func newDefDisk() defDisk {
 
 func newCDROM() defDisk {
 	disk := defDisk{}
-	disk.Type = "volume"
+	disk.Type = "file"
 	disk.Device = "cdrom"
 	disk.Target.Dev = "hda"
 	disk.Target.Bus = "ide"
diff --git a/libvirt/resource_libvirt_domain.go b/libvirt/resource_libvirt_domain.go
index 6be18fe4..106f5fed 100644
--- a/libvirt/resource_libvirt_domain.go
+++ b/libvirt/resource_libvirt_domain.go
@@ -260,21 +260,12 @@ func resourceLibvirtDomainCreate(d *schema.ResourceData, meta interface{}) error
 		if err != nil {
 			return fmt.Errorf("Can't retrieve volume %s", volumeKey)
 		}
-		diskVolumeName, err := diskVolume.GetName()
+		diskVolumeFile, err := diskVolume.GetPath()
 		if err != nil {
-			return fmt.Errorf("Error retrieving volume name: %s", err)
-		}
-		diskPool, err := diskVolume.LookupPoolByVolume()
-		if err != nil {
-			return fmt.Errorf("Error retrieving pool for volume: %s", err)
-		}
-		diskPoolName, err := diskPool.GetName()
-		if err != nil {
-			return fmt.Errorf("Error retrieving pool name: %s", err)
+			return fmt.Errorf("Error retrieving volume file: %s", err)
 		}
 
-		disk.Source.Volume = diskVolumeName
-		disk.Source.Pool = diskPoolName
+		disk.Source.File = diskVolumeFile
 
 		disks = append(disks, disk)
 	}
@@ -664,17 +655,23 @@ func resourceLibvirtDomainRead(d *schema.ResourceData, meta interface{}) error {
 
 	disks := make([]map[string]interface{}, 0)
 	for _, diskDef := range domainDef.Devices.Disks {
-		virPool, err := virConn.LookupStoragePoolByName(diskDef.Source.Pool)
-		if err != nil {
-			return fmt.Errorf("Error retrieving pool for disk: %s", err)
+		var virVol libvirt.VirStorageVol
+		if len(diskDef.Source.File) > 0 {
+			virVol, err = virConn.LookupStorageVolByPath(diskDef.Source.File)
+		} else {
+			virPool, err := virConn.LookupStoragePoolByName(diskDef.Source.Pool)
+			if err != nil {
+				return fmt.Errorf("Error retrieving pool for disk: %s", err)
+			}
+			defer virPool.Free()
+
+			virVol, err = virPool.LookupStorageVolByName(diskDef.Source.Volume)
 		}
-		defer virPool.Free()
+		defer virVol.Free()
 
-		virVol, err := virPool.LookupStorageVolByName(diskDef.Source.Volume)
 		if err != nil {
 			return fmt.Errorf("Error retrieving volume for disk: %s", err)
 		}
-		defer virVol.Free()
 
 		virVolKey, err := virVol.GetKey()
 		if err != nil {
@@ -964,21 +961,12 @@ func newDiskForCloudInit(virConn *libvirt.VirConnection, volumeKey string) (defD
 	if err != nil {
 		return disk, fmt.Errorf("Can't retrieve volume %s", volumeKey)
 	}
-	diskVolumeName, err := diskVolume.GetName()
-	if err != nil {
-		return disk, fmt.Errorf("Error retrieving volume name: %s", err)
-	}
-	diskPool, err := diskVolume.LookupPoolByVolume()
-	if err != nil {
-		return disk, fmt.Errorf("Error retrieving pool for volume: %s", err)
-	}
-	diskPoolName, err := diskPool.GetName()
+	diskVolumeFile, err := diskVolume.GetPath()
 	if err != nil {
-		return disk, fmt.Errorf("Error retrieving pool name: %s", err)
+		return disk, fmt.Errorf("Error retrieving volume file: %s", err)
 	}
 
-	disk.Source.Volume = diskVolumeName
-	disk.Source.Pool = diskPoolName
+	disk.Source.File = diskVolumeFile
 
 	return disk, nil
 }