use Ark version as the tag for the restore-helper image in init container

Signed-off-by: Steve Kriss <steve@heptio.com>

pkg/restore/restic_restore_action.go

@@ -17,6 +17,8 @@ limitations under the License.
 package restore
 
 import (
+	"fmt"
+
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
 
@@ -25,20 +27,33 @@ import (
 	"k8s.io/apimachinery/pkg/runtime"
 
 	api "github.com/heptio/ark/pkg/apis/ark/v1"
+	"github.com/heptio/ark/pkg/buildinfo"
 	"github.com/heptio/ark/pkg/restic"
 	"github.com/heptio/ark/pkg/util/kube"
 )
 
 type resticRestoreAction struct {
-	logger logrus.FieldLogger
+	logger             logrus.FieldLogger
+	initContainerImage string
 }
 
 func NewResticRestoreAction(logger logrus.FieldLogger) ItemAction {
 	return &resticRestoreAction{
-		logger: logger,
+		logger:             logger,
+		initContainerImage: initContainerImage(),
 	}
 }
 
+func initContainerImage() string {
+	tag := buildinfo.Version
+	if tag == "" {
+		tag = "latest"
+	}
+
+	// TODO allow full image URL to be overriden via CLI flag.
+	return fmt.Sprintf("gcr.io/heptio-images/ark-restic-restore-helper:%s", tag)
+}
+
 func (a *resticRestoreAction) AppliesTo() (ResourceSelector, error) {
 	return ResourceSelector{
 		IncludedResources: []string{"pods"},
@@ -65,11 +80,8 @@ func (a *resticRestoreAction) Execute(obj runtime.Unstructured, restore *api.Res
 	log.Info("Restic snapshot ID annotations found")
 
 	initContainer := corev1.Container{
-		Name: restic.InitContainer,
-		// TODO don't hardcode the tag as "latest". We should probably be defaulting
-		// to a tag that matches the Ark binary version, and possibly allowing it to
-		// be overriden via cmd-line flag to Ark.
-		Image: "gcr.io/heptio-images/ark-restic-restore-helper:latest",
+		Name:  restic.InitContainer,
+		Image: a.initContainerImage,
 		Args:  []string{string(restore.UID)},
 		Env: []corev1.EnvVar{
 			{