Golang Graph.From方法代码示例

// 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)
				}
			}
		}
	}
}

// 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
}

// 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.
// If pruneOverSizeLimit flag is set to true, above does not matter, instead
// all images size is checked against LimitRanges defined in that same namespace,
// and whenever its size exceeds the smallest limit in that namespace, it will be
// considered a candidate 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, limits map[string][]*kapi.LimitRange, 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 := unversioned.Now().Sub(stream.CreationTimestamp.Time)
		if !algorithm.pruneOverSizeLimit && age < algorithm.keepYoungerThan {
			// stream's age is below threshold - use a strong reference for old image revisions instead
			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) - skipping",
						history.Items[i].Image, tag, i, history.Items[i].DockerImageReference)
					continue
				}
				imageNode := n.(*imagegraph.ImageNode)

				kind := oldImageRevisionReferenceKind
				if algorithm.pruneOverSizeLimit {
					if exceedsLimits(stream, imageNode.Image, limits) {
						kind = WeakReferencedImageEdgeKind
					} else {
						kind = ReferencedImageEdgeKind
					}
				} else {
					if i < algorithm.keepTagRevisions {
						kind = ReferencedImageEdgeKind
					}
				}

				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=%s) from %q to %q", kind, imageStreamNode.UniqueName(), imageNode.UniqueName())
				g.AddEdge(imageStreamNode, imageNode, kind)

				glog.V(4).Infof("Adding stream->(layer|config) references")
				// add stream -> layer references so we can prune them later
				for _, s := range g.From(imageNode) {
					cn, ok := s.(*imagegraph.ImageComponentNode)
					if !ok {
						continue
					}

					glog.V(4).Infof("Adding reference from stream %q to %s", stream.Name, cn.Describe())
					if cn.Type == imagegraph.ImageComponentTypeConfig {
						g.AddEdge(imageStreamNode, s, ReferencedImageConfigEdgeKind)
					} else {
						g.AddEdge(imageStreamNode, s, ReferencedImageLayerEdgeKind)
					}
				}
			}
		}
	}
}