baremetal: Use static libvirt library to destroy cluster

Currently we link to a C-based dynamic library (via the libvirt-go
module) to connect to libvirt for the purposes of destroying a baremetal
cluster - which in fact only deletes the storage pools used by the
bootstrap (and is only used to clean up in cases where the installation
fails, since otherwise terraform will clean up when the bootstrap is
torn down).

The Terraform provider that actually creates the bootstrap uses a
pure-Golang library (go-libvirt). By switching to that same library here
we can avoid the need to dynamically link to libvirt.

Author: zaneb

pkg/destroy/baremetal/baremetal.go

@@ -4,7 +4,9 @@
 package baremetal
 
 import (
-	"github.com/libvirt/libvirt-go"
+	"net/url"
+
+	libvirt "github.com/digitalocean/go-libvirt"
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
 
@@ -24,17 +26,27 @@ type ClusterUninstaller struct {
 func (o *ClusterUninstaller) Run() (*types.ClusterQuota, error) {
 	o.Logger.Debug("Deleting bare metal resources")
 
-	// FIXME: close the connection
-	conn, err := libvirt.NewConnect(o.LibvirtURI)
+	uri, err := url.Parse(o.LibvirtURI)
 	if err != nil {
-		return nil, errors.Wrap(err, "failed to connect to Libvirt daemon")
+		return nil, err
 	}
-	err = o.deleteStoragePool(conn)
+
+	virt, err := libvirt.ConnectToURI(uri)
 	if err != nil {
-		return nil, errors.Wrap(err, "failed to clean baremetal bootstrap storage pool")
+		return nil, err
 	}
+	defer func() {
+		if err := virt.Disconnect(); err != nil {
+			if o.Logger != nil {
+				o.Logger.Warn("failed to disconnect from libvirt", err)
+			}
+		}
+	}()
 
-	o.Logger.Debug("FIXME: delete resources!")
+	err = o.deleteStoragePool(virt)
+	if err != nil {
+		return nil, errors.Wrap(err, "failed to clean baremetal bootstrap storage pool")
+	}
 
 	return nil, nil
 }
@@ -51,47 +63,45 @@ func New(logger logrus.FieldLogger, metadata *types.ClusterMetadata) (providers.
 
 // deleteStoragePool destroys, deletes and undefines any storagePool left behind during the creation
 // of the bootstrap VM
-func (o *ClusterUninstaller) deleteStoragePool(conn *libvirt.Connect) error {
+func (o *ClusterUninstaller) deleteStoragePool(virt *libvirt.Libvirt) error {
 	o.Logger.Debug("Deleting baremetal bootstrap volumes")
 
 	pName := o.InfraID + "-bootstrap"
-	pool, err := conn.LookupStoragePoolByName(pName)
+	pool, err := virt.StoragePoolLookupByName(pName)
 	if err != nil {
 		o.Logger.Warnf("Unable to get storage pool %s: %s", pName, err)
 		return nil
 	}
-	defer pool.Free()
 
 	// delete vols
-	vols, err := pool.ListAllStorageVolumes(0)
+	vols, err := virt.StoragePoolListVolumes(pool, 0)
 	if err != nil {
 		o.Logger.Warnf("Unable to get volumes in storage pool %s: %s", pName, err)
 		return nil
 	}
 
-	for _, vol := range vols {
-		defer vol.Free()
-		vName, err := vol.GetName()
+	for _, vName := range vols {
+		vol, err := virt.StorageVolLookupByName(pool, vName)
 		if err != nil {
 			o.Logger.Warnf("Unable to get volume %s in storage pool %s: %s", vName, pName, err)
 			return nil
 		}
-		if err := vol.Delete(0); err != nil {
+		if err := virt.StorageVolDelete(vol, 0); err != nil {
 			o.Logger.Warnf("Unable to delete volume %s in storage pool %s: %s", vName, pName, err)
 			return nil
 		}
 		o.Logger.WithField("volume", vName).Info("Deleted volume")
 	}
 
-	if err := pool.Destroy(); err != nil {
+	if err := virt.StoragePoolDestroy(pool); err != nil {
 		o.Logger.Warnf("Unable to destroy storage pool %s: %s", pName, err)
 	}
 
-	if err := pool.Delete(0); err != nil {
+	if err := virt.StoragePoolDelete(pool, 0); err != nil {
 		o.Logger.Warnf("Unable to delete storage pool %s: %s", pName, err)
 	}
 
-	if err := pool.Undefine(); err != nil {
+	if err := virt.StoragePoolUndefine(pool); err != nil {
 		o.Logger.Warnf("Unable to undefine storage pool %s: %s", pName, err)
 	}
 	o.Logger.WithField("pool", pName).Info("Deleted pool")