image-pruner: prune images in their own jobs

Instead of pruning in phases:

    all streams -> all layers -> all blobs -> manifests -> images

Prune individual images in parallel jobs:

    all streams -> parallel [
       image1's layers -> image1's blobs -> ... -> image1,
       image2's layers -> image2's blobs -> ... -> image2,
       ...
    ]

A failure in streams prune phase is not fatal anymore.

Signed-off-by: Michal Minář <[email protected]>

Author: Michal Minář

pkg/oc/admin/prune/imageprune/helper.go

@@ -7,6 +7,10 @@ import (
 	"sort"
 	"strings"
 
+	kmeta "k8s.io/apimachinery/pkg/api/meta"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/kubernetes/pkg/api/legacyscheme"
+	kapiref "k8s.io/kubernetes/pkg/api/ref"
 	kapi "k8s.io/kubernetes/pkg/apis/core"
 
 	"github.com/docker/distribution/registry/api/errcode"
@@ -265,3 +269,36 @@ func (e *ErrBadReference) String() string {
 	}
 	return fmt.Sprintf("%s[%s]: invalid %s reference %q: %s", e.kind, name, targetKind, e.reference, e.reason)
 }
+
+func getName(obj runtime.Object) string {
+	accessor, err := kmeta.Accessor(obj)
+	if err != nil {
+		glog.V(4).Infof("Error getting accessor for %#v", obj)
+		return "<unknown>"
+	}
+	ns := accessor.GetNamespace()
+	if len(ns) == 0 {
+		return accessor.GetName()
+	}
+	return fmt.Sprintf("%s/%s", ns, accessor.GetName())
+}
+
+func getKindName(obj *kapi.ObjectReference) string {
+	if obj == nil {
+		return "unknown object"
+	}
+	name := obj.Name
+	if len(obj.Namespace) > 0 {
+		name = obj.Namespace + "/" + name
+	}
+	return fmt.Sprintf("%s[%s]", obj.Kind, name)
+}
+
+func getRef(obj runtime.Object) *kapi.ObjectReference {
+	ref, err := kapiref.GetReference(legacyscheme.Scheme, obj)
+	if err != nil {
+		glog.Errorf("failed to get reference to object %T: %v", obj, err)
+		return nil
+	}
+	return ref
+}