@@ -1553,6 +1553,7 @@ _oadm_build-chain()

     flags+=("--all")

     flags+=("--output=")

     two_word_flags+=("-o")

+    flags+=("--reverse")

     flags+=("--trigger-only")

     flags+=("--api-version=")

     flags+=("--certificate-authority=")

@@ -4398,6 +4398,7 @@ _oc_adm_build-chain()

     flags+=("--all")

     flags+=("--output=")

     two_word_flags+=("-o")

+    flags+=("--reverse")

     flags+=("--trigger-only")

     flags+=("--api-version=")

     flags+=("--certificate-authority=")

@@ -2130,6 +2130,7 @@ _openshift_admin_build-chain()

     flags+=("--all")

     flags+=("--output=")

     two_word_flags+=("-o")

+    flags+=("--reverse")

     flags+=("--trigger-only")

     flags+=("--api-version=")

     flags+=("--certificate-authority=")

@@ -7949,6 +7950,7 @@ _openshift_cli_adm_build-chain()

     flags+=("--all")

     flags+=("--output=")

     two_word_flags+=("-o")

+    flags+=("--reverse")

     flags+=("--trigger-only")

     flags+=("--api-version=")

     flags+=("--certificate-authority=")

@@ -14690,6 +14692,7 @@ _openshift_ex_build-chain()

     flags+=("--all")

     flags+=("--output=")

     two_word_flags+=("-o")

+    flags+=("--reverse")

     flags+=("--trigger-only")

     flags+=("--api-version=")

     flags+=("--certificate-authority=")

@@ -434,6 +434,17 @@ func RemoveInboundEdges(nodes []graph.Node) EdgeFunc {

 	}

 }

+func RemoveOutboundEdges(nodes []graph.Node) EdgeFunc {

+	return func(g Interface, from, to graph.Node, edgeKinds sets.String) bool {

+		for _, node := range nodes {

+			if node == from {

+				return false

+			}

+		}

+		return true

+	}

+}

+

 // EdgeSubgraph returns the directed subgraph with only the edges that match the

 // provided function.

 func (g Graph) EdgeSubgraph(edgeFn EdgeFunc) Graph {

@@ -23,9 +23,9 @@ import (

 )

 // NotFoundErr is returned when the imageStreamTag (ist) of interest cannot

-// be found in the graph. This doesn't mean though that the ist does not

+// be found in the graph. This doesn't mean though that the IST does not

 // exist. A user may have an image stream without a build configuration

-// pointing at it. In that case, the ist of interest simply doesn't have

+// pointing at it. In that case, the IST of interest simply doesn't have

 // other dependant ists

 type NotFoundErr string

@@ -79,7 +79,7 @@ func (d *ChainDescriber) MakeGraph() (osgraph.Graph, error) {

 // image stream tag (name:tag) in namespace. Namespace is needed here

 // because image stream tags with the same name can be found across

 // different namespaces.

-func (d *ChainDescriber) Describe(ist *imageapi.ImageStreamTag, includeInputImages bool) (string, error) {

+func (d *ChainDescriber) Describe(ist *imageapi.ImageStreamTag, includeInputImages, reverse bool) (string, error) {

 	g, err := d.MakeGraph()

 	if err != nil {

 		return "", err

@@ -96,8 +96,13 @@ func (d *ChainDescriber) Describe(ist *imageapi.ImageStreamTag, includeInputImag

 		buildInputEdgeKinds = append(buildInputEdgeKinds, buildedges.BuildInputImageEdgeKind)

 	}

-	// Partition down to the subgraph containing the ist of interest

-	partitioned := partition(g, istNode, buildInputEdgeKinds)

+	// Partition down to the subgraph containing the imagestreamtag of interest

+	var partitioned osgraph.Graph

+	if reverse {

+		partitioned = partitionReverse(g, istNode, buildInputEdgeKinds)

+	} else {

+		partitioned = partition(g, istNode, buildInputEdgeKinds)

+	}

 	switch strings.ToLower(d.outputFormat) {

 	case "dot":

@@ -107,7 +112,7 @@ func (d *ChainDescriber) Describe(ist *imageapi.ImageStreamTag, includeInputImag

 		}

 		return string(data), nil

 	case "":

-		return d.humanReadableOutput(partitioned, d.namer, istNode), nil

+		return d.humanReadableOutput(partitioned, d.namer, istNode, reverse), nil

 	}

 	return "", fmt.Errorf("unknown specified format %q", d.outputFormat)

@@ -124,7 +129,7 @@ func partition(g osgraph.Graph, root graph.Node, buildInputEdgeKinds []string) o

 	edgeFn := osgraph.EdgesOfKind(edgeKinds...)

 	sub := g.Subgraph(nodeFn, edgeFn)

-	// Filter out inbound edges to the ist of interest

+	// Filter out inbound edges to the IST of interest

 	edgeFn = osgraph.RemoveInboundEdges([]graph.Node{root})

 	sub = sub.Subgraph(nodeFn, edgeFn)

@@ -144,11 +149,46 @@ func partition(g osgraph.Graph, root graph.Node, buildInputEdgeKinds []string) o

 	return sub.SubgraphWithNodes(desired, osgraph.ExistingDirectEdge)

 }

+// partitionReverse the graph down to a subgraph starting from the given root

+func partitionReverse(g osgraph.Graph, root graph.Node, buildInputEdgeKinds []string) osgraph.Graph {

+	// Filter out all but BuildConfig and ImageStreamTag nodes

+	nodeFn := osgraph.NodesOfKind(buildgraph.BuildConfigNodeKind, imagegraph.ImageStreamTagNodeKind)

+	// Filter out all but BuildInputImage and BuildOutput edges

+	edgeKinds := []string{}

+	edgeKinds = append(edgeKinds, buildInputEdgeKinds...)

+	edgeKinds = append(edgeKinds, buildedges.BuildOutputEdgeKind)

+	edgeFn := osgraph.EdgesOfKind(edgeKinds...)

+	sub := g.Subgraph(nodeFn, edgeFn)

+

+	// Filter out inbound edges to the IST of interest

+	edgeFn = osgraph.RemoveOutboundEdges([]graph.Node{root})

+	sub = sub.Subgraph(nodeFn, edgeFn)

+

+	// Check all paths leading from the root node, collect any

+	// node found in them, and create the desired subgraph

+	desired := []graph.Node{root}

+	paths := path.DijkstraAllPaths(sub)

+	for _, node := range sub.Nodes() {

+		if node == root {

+			continue

+		}

+		path, _, _ := paths.Between(node, root)

+		if len(path) != 0 {

+			desired = append(desired, node)

+		}

+	}

+	return sub.SubgraphWithNodes(desired, osgraph.ExistingDirectEdge)

+}

+

 // humanReadableOutput traverses the provided graph using DFS and outputs it

 // in a human-readable format. It starts from the provided root, assuming it

 // is an imageStreamTag node and continues to the rest of the graph handling

 // only imageStreamTag and buildConfig nodes.

-func (d *ChainDescriber) humanReadableOutput(g osgraph.Graph, f osgraph.Namer, root graph.Node) string {

+func (d *ChainDescriber) humanReadableOutput(g osgraph.Graph, f osgraph.Namer, root graph.Node, reverse bool) string {

+	if reverse {

+		g = g.EdgeSubgraph(osgraph.ReverseExistingDirectEdge)

+	}

+

 	var singleNamespace bool

 	if len(d.namespaces) == 1 && !d.namespaces.Has(kapi.NamespaceAll) {

 		singleNamespace = true

@@ -19,6 +19,7 @@ func TestChainDescriber(t *testing.T) {

 		testName         string

 		namespaces       sets.String

 		output           string

+		reverse          bool

 		defaultNamespace string

 		name             string

 		tag              string

@@ -161,6 +162,24 @@ func TestChainDescriber(t *testing.T) {

 				"\t\tistag/parent3img:latest":    1,

 			},

 		},

+		{

+			testName:         "human readable - multiple triggers - triggeronly - reverse",

+			name:             "child2img",

+			reverse:          true,

+			defaultNamespace: "test",

+			tag:              "latest",

+			path:             "../../../../pkg/cmd/experimental/buildchain/test/multiple-trigger-bcs.yaml",

+			namespaces:       sets.NewString("test"),

+			humanReadable: map[string]int{

+				"istag/child2img:latest":               1,

+				"\tbc/child2":                          1,

+				"\t\tistag/parent1img:latest":          1,

+				"\t\t\tbc/parent1":                     1,

+				"\t\t\t\tistag/ruby-22-centos7:latest": 2,

+				"\t\tistag/parent3img:latest":          1,

+				"\t\t\tbc/parent3":                     1,

+			},

+		},

 	}

 	for _, test := range tests {

@@ -174,7 +193,7 @@ func TestChainDescriber(t *testing.T) {

 		oc, _ := testclient.NewFixtureClients(o)

 		ist := imagegraph.MakeImageStreamTagObjectMeta(test.defaultNamespace, test.name, test.tag)

-		desc, err := NewChainDescriber(oc, test.namespaces, test.output).Describe(ist, test.includeInputImg)

+		desc, err := NewChainDescriber(oc, test.namespaces, test.output).Describe(ist, test.includeInputImg, test.reverse)

 		t.Logf("%s: output:\n%s\n\n", test.testName, desc)

 		if err != test.expectedErr {

 			t.Fatalf("%s: error mismatch: expected %v, got %v", test.testName, test.expectedErr, err)

@@ -49,6 +49,7 @@ type BuildChainOptions struct {

 	namespaces       sets.String

 	allNamespaces    bool

 	triggerOnly      bool

+	reverse          bool

 	output string

@@ -77,6 +78,7 @@ func NewCmdBuildChain(name, fullName string, f *clientcmd.Factory, out io.Writer

 	cmd.Flags().BoolVar(&options.allNamespaces, "all", false, "Build dependency tree for the specified image stream tag across all namespaces")

 	cmd.Flags().BoolVar(&options.triggerOnly, "trigger-only", true, "If true, only include dependencies based on build triggers. If false, include all dependencies.")

+	cmd.Flags().BoolVar(&options.reverse, "reverse", false, "If true, show the istags dependencies instead of its dependants.")

 	cmd.Flags().StringVarP(&options.output, "output", "o", "", "Output format of dependency tree")

 	return cmd

 }

@@ -160,7 +162,7 @@ func (o *BuildChainOptions) Validate() error {

 func (o *BuildChainOptions) RunBuildChain() error {

 	ist := imagegraph.MakeImageStreamTagObjectMeta2(o.defaultNamespace, o.name)

-	desc, err := describe.NewChainDescriber(o.c, o.namespaces, o.output).Describe(ist, !o.triggerOnly)

+	desc, err := describe.NewChainDescriber(o.c, o.namespaces, o.output).Describe(ist, !o.triggerOnly, o.reverse)

 	if err != nil {

 		if _, isNotFoundErr := err.(describe.NotFoundErr); isNotFoundErr {

 			name, tag, _ := imageapi.SplitImageStreamTag(o.name)