// addImageStreamsToGraph adds all the streams to the graph. The most recent n
// image revisions for a tag will be preserved, where n is specified by the
// algorithm's keepTagRevisions. Image revisions older than n are candidates
// for pruning. if the image stream's age is at least as old as the minimum
// threshold in algorithm. Otherwise, if the image stream is younger than the
// threshold, all image revisions for that stream are ineligible for pruning.
//
// addImageStreamsToGraph also adds references from each stream to all the
// layers it references (via each image a stream references).
func addImageStreamsToGraph(g graph.Graph, streams *imageapi.ImageStreamList, algorithm pruneAlgorithm) {
for i := range streams.Items {
stream := &streams.Items[i]
glog.V(4).Infof("Examining ImageStream %s/%s", stream.Namespace, stream.Name)
// use a weak reference for old image revisions by default
oldImageRevisionReferenceKind := WeakReferencedImageEdgeKind
age := util.Now().Sub(stream.CreationTimestamp.Time)
if age < algorithm.keepYoungerThan {
// stream's age is below threshold - use a strong reference for old image revisions instead
glog.V(4).Infof("Stream %s/%s is below age threshold - none of its images are eligible for pruning", stream.Namespace, stream.Name)
oldImageRevisionReferenceKind = ReferencedImageEdgeKind
}
glog.V(4).Infof("Adding ImageStream %s/%s to graph", stream.Namespace, stream.Name)
isNode := imagegraph.EnsureImageStreamNode(g, stream)
imageStreamNode := isNode.(*imagegraph.ImageStreamNode)
for tag, history := range stream.Status.Tags {
for i := range history.Items {
n := imagegraph.FindImage(g, history.Items[i].Image)
if n == nil {
glog.V(2).Infof("Unable to find image %q in graph (from tag=%q, revision=%d, dockerImageReference=%s)", history.Items[i].Image, tag, i, history.Items[i].DockerImageReference)
continue
}
imageNode := n.(*imagegraph.ImageNode)
var kind string
switch {
case i < algorithm.keepTagRevisions:
kind = ReferencedImageEdgeKind
default:
kind = oldImageRevisionReferenceKind
}
glog.V(4).Infof("Checking for existing strong reference from stream %s/%s to image %s", stream.Namespace, stream.Name, imageNode.Image.Name)
if edge := g.Edge(imageStreamNode, imageNode); edge != nil && g.EdgeKinds(edge).Has(ReferencedImageEdgeKind) {
glog.V(4).Infof("Strong reference found")
continue
}
glog.V(4).Infof("Adding edge (kind=%d) from %q to %q", kind, imageStreamNode.UniqueName.UniqueName(), imageNode.UniqueName.UniqueName())
g.AddEdge(imageStreamNode, imageNode, kind)
glog.V(4).Infof("Adding stream->layer references")
// add stream -> layer references so we can prune them later
for _, s := range g.From(imageNode) {
if g.Kind(s) != imagegraph.ImageLayerNodeKind {
continue
}
glog.V(4).Infof("Adding reference from stream %q to layer %q", stream.Name, s.(*imagegraph.ImageLayerNode).Layer)
g.AddEdge(imageStreamNode, s, ReferencedImageLayerEdgeKind)
}
}
}
}
}
// layerIsPrunable returns true if the layer is not referenced by any images.
func layerIsPrunable(g graph.Graph, layerNode *imagegraph.ImageLayerNode) bool {
for _, predecessor := range g.To(layerNode) {
glog.V(4).Infof("Examining layer predecessor %#v", predecessor)
if g.Kind(predecessor) == imagegraph.ImageNodeKind {
glog.V(4).Infof("Layer has an image predecessor")
return false
}
}
return true
}
// streamReferencingImageComponent returns a list of ImageStreamNodes that reference a
// given ImageComponentNode.
func streamsReferencingImageComponent(g graph.Graph, cn *imagegraph.ImageComponentNode) []*imagegraph.ImageStreamNode {
ret := []*imagegraph.ImageStreamNode{}
for _, predecessor := range g.To(cn) {
if g.Kind(predecessor) != imagegraph.ImageStreamNodeKind {
continue
}
ret = append(ret, predecessor.(*imagegraph.ImageStreamNode))
}
return ret
}
// imageComponentIsPrunable returns true if the image component is not referenced by any images.
func imageComponentIsPrunable(g graph.Graph, cn *imagegraph.ImageComponentNode) bool {
for _, predecessor := range g.To(cn) {
glog.V(4).Infof("Examining predecessor %#v of image config %v", predecessor, cn)
if g.Kind(predecessor) == imagegraph.ImageNodeKind {
glog.V(4).Infof("Config %v has an image predecessor", cn)
return false
}
}
return true
}
// streamLayerReferences returns a list of ImageStreamNodes that reference a
// given ImageLayerNode.
func streamLayerReferences(g graph.Graph, layerNode *imagegraph.ImageLayerNode) []*imagegraph.ImageStreamNode {
ret := []*imagegraph.ImageStreamNode{}
for _, predecessor := range g.To(layerNode) {
if g.Kind(predecessor) != imagegraph.ImageStreamNodeKind {
continue
}
ret = append(ret, predecessor.(*imagegraph.ImageStreamNode))
}
return ret
}
// DescendentNodesByNodeKind starts at the root navigates down the root. Every edge is checked against the edgeChecker
// to determine whether or not to follow it. The nodes at the tail end of every chased edge are then checked against the
// the targetNodeKind. Matches are added to the return and every checked node then has its edges checked: lather, rinse, repeat
func DescendentNodesByNodeKind(g osgraph.Graph, visitedNodes graphview.IntSet, node graph.Node, targetNodeKind string, edgeChecker osgraph.EdgeFunc) []graph.Node {
if visitedNodes.Has(node.ID()) {
return []graph.Node{}
}
visitedNodes.Insert(node.ID())
ret := []graph.Node{}
for _, successor := range g.From(node) {
edge := g.Edge(node, successor)
if edgeChecker(osgraph.New(), node, successor, g.EdgeKinds(edge)) {
if g.Kind(successor) == targetNodeKind {
ret = append(ret, successor)
}
ret = append(ret, DescendentNodesByNodeKind(g, visitedNodes, successor, targetNodeKind, edgeChecker)...)
}
}
return ret
}