Allow to specify the base volume by using a name

It's now possible to specify a base volume by using the
`base_volume_name`. This is an approach done also by other Terraform
providers: either use an "internal" ID or a human-friendly name.

This makes easier to share the same base volume between different
terraform projects.

Signed-off-by: Flavio Castelli <fcastelli@suse.com>

2 files changed, 49 insertions, 2 deletions

diff --git a/docs/providers/libvirt/r/volume.html.markdown b/docs/providers/libvirt/r/volume.html.markdown
index d7f18783..f76c718b 100644
--- a/docs/providers/libvirt/r/volume.html.markdown
+++ b/docs/providers/libvirt/r/volume.html.markdown
@@ -34,4 +34,5 @@ The following arguments are supported:
 * `size` - (Optional) The size of the volume in bytes (if you don't like this, help fix [this issue](https://github.com/hashicorp/terraform/issues/3287).
    If `source` is specified, `size` will be set to the source image file size.
 * `base_volume_id` - (Optional) The backing volume (CoW) to use for this volume.
-
+* `base_volume_name` - (Optional) The name of the backing volume (CoW) to use for this volume. Note well: when `base_volume_pool` is not specified the volume is going to be searched inside of `pool`.
+* `base_volume_pool` - (Optional) The name of the pool containing the volume defined by `base_volume_name`.
diff --git a/libvirt/resource_libvirt_volume.go b/libvirt/resource_libvirt_volume.go
index 588774d1..af565e15 100644
--- a/libvirt/resource_libvirt_volume.go
+++ b/libvirt/resource_libvirt_volume.go
@@ -136,6 +136,16 @@ func volumeCommonSchema() map[string]*schema.Schema {
 			Optional: true,
 			ForceNew: true,
 		},
+		"base_volume_pool": &schema.Schema{
+			Type:     schema.TypeString,
+			Optional: true,
+			ForceNew: true,
+		},
+		"base_volume_name": &schema.Schema{
+			Type:     schema.TypeString,
+			Optional: true,
+			ForceNew: true,
+		},
 	}
 }
 
@@ -196,7 +206,11 @@ func resourceLibvirtVolumeCreate(d *schema.ResourceData, meta interface{}) error
 			return fmt.Errorf("'size' can't be specified when also 'source' is given (the size will be set to the size of the source image.")
 		}
 		if _, ok := d.GetOk("base_volume_id"); ok {
-			return fmt.Errorf("'base_volume_id' can't be specified when also 'source' is given (the size will be set to the size of the base image.")
+			return fmt.Errorf("'base_volume_id' can't be specified when also 'source' is given.")
+		}
+
+		if _, ok := d.GetOk("base_volume_name"); ok {
+			return fmt.Errorf("'base_volume_name' can't be specified when also 'source' is given.")
 		}
 
 		img, err := newImage(url.(string))
@@ -227,6 +241,10 @@ func resourceLibvirtVolumeCreate(d *schema.ResourceData, meta interface{}) error
 			return fmt.Errorf("'size' can't be specified when also 'base_volume_id' is given (the size will be set to the size of the backing image.")
 		}
 
+		if _, ok := d.GetOk("base_volume_name"); ok {
+			return fmt.Errorf("'base_volume_name' can't be specified when also 'base_volume_id' is given.")
+		}
+
 		volumeDef.BackingStore = new(defBackingStore)
 		volumeDef.BackingStore.Format.Type = "qcow2"
 		baseVolume, err := virConn.LookupStorageVolByKey(baseVolumeId.(string))
@@ -240,6 +258,34 @@ func resourceLibvirtVolumeCreate(d *schema.ResourceData, meta interface{}) error
 		volumeDef.BackingStore.Path = baseVolPath
 	}
 
+	if baseVolumeName, ok := d.GetOk("base_volume_name"); ok {
+		if _, ok := d.GetOk("size"); ok {
+			return fmt.Errorf("'size' can't be specified when also 'base_volume_name' is given (the size will be set to the size of the backing image.")
+		}
+
+		baseVolumePool := pool
+		if _, ok := d.GetOk("base_volume_pool"); ok {
+			baseVolumePoolName := d.Get("base_volume_pool").(string)
+			baseVolumePool, err = virConn.LookupStoragePoolByName(baseVolumePoolName)
+			if err != nil {
+				return fmt.Errorf("can't find storage pool '%s'", baseVolumePoolName)
+			}
+			defer baseVolumePool.Free()
+		}
+
+		volumeDef.BackingStore = new(defBackingStore)
+		volumeDef.BackingStore.Format.Type = "qcow2"
+		baseVolume, err := baseVolumePool.LookupStorageVolByName(baseVolumeName.(string))
+		if err != nil {
+			return fmt.Errorf("Can't retrieve volume %s", baseVolumeName.(string))
+		}
+		baseVolPath, err := baseVolume.GetPath()
+		if err != nil {
+			return fmt.Errorf("can't get name for base image '%s'", baseVolumeName)
+		}
+		volumeDef.BackingStore.Path = baseVolPath
+	}
+
 	volumeDefXml, err := xml.Marshal(volumeDef)
 	if err != nil {
 		return fmt.Errorf("Error serializing libvirt volume: %s", err)