Add image pruning

pkg/api/graph/graph.go

@@ -23,6 +23,10 @@ type uniqueNamer interface {
 	UniqueName() string
 }
 
+type NodeFinder interface {
+	Find(name UniqueName) graph.Node
+}
+
 // UniqueNodeInitializer is a graph that allows nodes with a unique name to be added without duplication.
 // If the node is newly added, true will be returned.
 type UniqueNodeInitializer interface {
@@ -44,6 +48,7 @@ type MutableUniqueGraph interface {
 	graph.Mutable
 	MutableDirectedEdge
 	UniqueNodeInitializer
+	NodeFinder
 }
 
 type Edge struct {
@@ -294,6 +299,13 @@ func (g uniqueNamedGraph) FindOrCreate(name UniqueName, fn NodeInitializerFunc)
 	return node, false
 }
 
+func (g uniqueNamedGraph) Find(name UniqueName) graph.Node {
+	if node, ok := g.names[name]; ok {
+		return node
+	}
+	return nil
+}
+
 type typedGraph struct{}
 
 type stringer interface {

pkg/api/graph/graph_test.go

@@ -188,7 +188,8 @@ func TestGraph(t *testing.T) {
 			}
 			bc++
 		case *image.ImageStream:
-			if g.Kind(node) != ImageStreamGraphKind {
+			// TODO resolve this check for 2 kinds, since both have the same object type
+			if g.Kind(node) != ImageStreamGraphKind && g.Kind(node) != ImageStreamTagGraphKind {
 				t.Fatalf("unexpected kind: %v", g.Kind(node))
 			}
 			ir++