Reimplement GC dot graph dumping without gonum library

pkg/controller/garbagecollector/dump.go

@@ -17,22 +17,20 @@ limitations under the License.
 package garbagecollector
 
 import (
+	"bytes"
 	"fmt"
+	"io"
 	"net/http"
+	"sort"
 	"strings"
 
-	"gonum.org/v1/gonum/graph"
-	"gonum.org/v1/gonum/graph/encoding"
-	"gonum.org/v1/gonum/graph/encoding/dot"
-	"gonum.org/v1/gonum/graph/simple"
-
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/runtime/schema"
 	"k8s.io/apimachinery/pkg/types"
 	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
 )
 
-type gonumVertex struct {
+type dotVertex struct {
 	uid                types.UID
 	gvk                schema.GroupVersionKind
 	namespace          string
@@ -41,14 +39,25 @@ type gonumVertex struct {
 	beingDeleted       bool
 	deletingDependents bool
 	virtual            bool
-	vertexID           int64
 }
 
-func (v *gonumVertex) ID() int64 {
+func (v *dotVertex) MarshalDOT(w io.Writer) error {
-	return v.vertexID
+	attrs := v.Attributes()
+	if _, err := fmt.Fprintf(w, "  %q [\n", v.uid); err != nil {
+		return err
+	}
+	for _, a := range attrs {
+		if _, err := fmt.Fprintf(w, "    %s=%q\n", a.Key, a.Value); err != nil {
+			return err
+		}
+	}
+	if _, err := fmt.Fprintf(w, "  ];\n"); err != nil {
+		return err
+	}
+	return nil
 }
 
-func (v *gonumVertex) String() string {
+func (v *dotVertex) String() string {
 	kind := v.gvk.Kind + "." + v.gvk.Version
 	if len(v.gvk.Group) > 0 {
 		kind = kind + "." + v.gvk.Group
@@ -72,7 +81,12 @@ func (v *gonumVertex) String() string {
 	return fmt.Sprintf(`%s/%s[%s]-%v%s%s%s%s`, kind, v.name, v.namespace, v.uid, missing, deleting, deletingDependents, virtual)
 }
 
-func (v *gonumVertex) Attributes() []encoding.Attribute {
+type attribute struct {
+	Key   string
+	Value string
+}
+
+func (v *dotVertex) Attributes() []attribute {
 	kubectlString := v.gvk.Kind + "." + v.gvk.Version
 	if len(v.gvk.Group) > 0 {
 		kubectlString = kubectlString + "." + v.gvk.Group
@@ -106,30 +120,30 @@ namespace=%v
 		label = label + conditionString + "\n"
 	}
 
-	return []encoding.Attribute{
+	return []attribute{
-		{Key: "label", Value: fmt.Sprintf(`"%v"`, label)},
+		{Key: "label", Value: label},
 		// these place metadata in the correct location, but don't conform to any normal attribute for rendering
-		{Key: "group", Value: fmt.Sprintf(`"%v"`, v.gvk.Group)},
+		{Key: "group", Value: v.gvk.Group},
-		{Key: "version", Value: fmt.Sprintf(`"%v"`, v.gvk.Version)},
+		{Key: "version", Value: v.gvk.Version},
-		{Key: "kind", Value: fmt.Sprintf(`"%v"`, v.gvk.Kind)},
+		{Key: "kind", Value: v.gvk.Kind},
-		{Key: "namespace", Value: fmt.Sprintf(`"%v"`, v.namespace)},
+		{Key: "namespace", Value: v.namespace},
-		{Key: "name", Value: fmt.Sprintf(`"%v"`, v.name)},
+		{Key: "name", Value: v.name},
-		{Key: "uid", Value: fmt.Sprintf(`"%v"`, v.uid)},
+		{Key: "uid", Value: string(v.uid)},
-		{Key: "missing", Value: fmt.Sprintf(`"%v"`, v.missingFromGraph)},
+		{Key: "missing", Value: fmt.Sprintf(`%v`, v.missingFromGraph)},
-		{Key: "beingDeleted", Value: fmt.Sprintf(`"%v"`, v.beingDeleted)},
+		{Key: "beingDeleted", Value: fmt.Sprintf(`%v`, v.beingDeleted)},
-		{Key: "deletingDependents", Value: fmt.Sprintf(`"%v"`, v.deletingDependents)},
+		{Key: "deletingDependents", Value: fmt.Sprintf(`%v`, v.deletingDependents)},
-		{Key: "virtual", Value: fmt.Sprintf(`"%v"`, v.virtual)},
+		{Key: "virtual", Value: fmt.Sprintf(`%v`, v.virtual)},
 	}
 }
 
-// NewGonumVertex creates a new gonumVertex.
+// NewDOTVertex creates a new dotVertex.
-func NewGonumVertex(node *node, nodeID int64) *gonumVertex {
+func NewDOTVertex(node *node) *dotVertex {
 	gv, err := schema.ParseGroupVersion(node.identity.APIVersion)
 	if err != nil {
 		// this indicates a bad data serialization that should be prevented during storage of the API
 		utilruntime.HandleError(err)
 	}
-	return &gonumVertex{
+	return &dotVertex{
 		uid:                node.identity.UID,
 		gvk:                gv.WithKind(node.identity.Kind),
 		namespace:          node.identity.Namespace,
@@ -137,36 +151,46 @@ func NewGonumVertex(node *node, nodeID int64) *gonumVertex {
 		beingDeleted:       node.beingDeleted,
 		deletingDependents: node.deletingDependents,
 		virtual:            node.virtual,
-		vertexID:           nodeID,
 	}
 }
 
-// NewMissingGonumVertex creates a new gonumVertex.
+// NewMissingdotVertex creates a new dotVertex.
-func NewMissingGonumVertex(ownerRef metav1.OwnerReference, nodeID int64) *gonumVertex {
+func NewMissingdotVertex(ownerRef metav1.OwnerReference) *dotVertex {
 	gv, err := schema.ParseGroupVersion(ownerRef.APIVersion)
 	if err != nil {
 		// this indicates a bad data serialization that should be prevented during storage of the API
 		utilruntime.HandleError(err)
 	}
-	return &gonumVertex{
+	return &dotVertex{
 		uid:              ownerRef.UID,
 		gvk:              gv.WithKind(ownerRef.Kind),
 		name:             ownerRef.Name,
 		missingFromGraph: true,
-		vertexID:         nodeID,
 	}
 }
 
-func (m *concurrentUIDToNode) ToGonumGraph() graph.Directed {
+func (m *concurrentUIDToNode) ToDOTNodesAndEdges() ([]*dotVertex, []dotEdge) {
 	m.uidToNodeLock.Lock()
 	defer m.uidToNodeLock.Unlock()
 
-	return toGonumGraph(m.uidToNode)
+	return toDOTNodesAndEdges(m.uidToNode)
 }
 
-func toGonumGraph(uidToNode map[types.UID]*node) graph.Directed {
+type dotEdge struct {
-	uidToVertex := map[types.UID]*gonumVertex{}
+	F types.UID
-	graphBuilder := simple.NewDirectedGraph()
+	T types.UID
+}
+
+func (e dotEdge) MarshalDOT(w io.Writer) error {
+	_, err := fmt.Fprintf(w, "  %q -> %q;\n", e.F, e.T)
+	return err
+}
+
+func toDOTNodesAndEdges(uidToNode map[types.UID]*node) ([]*dotVertex, []dotEdge) {
+	nodes := []*dotVertex{}
+	edges := []dotEdge{}
+
+	uidToVertex := map[types.UID]*dotVertex{}
 
 	// add the vertices first, then edges.  That avoids having to deal with missing refs.
 	for _, node := range uidToNode {
@@ -174,38 +198,42 @@ func toGonumGraph(uidToNode map[types.UID]*node) graph.Directed {
 		if len(node.dependents) == 0 && len(node.owners) == 0 {
 			continue
 		}
-		vertex := NewGonumVertex(node, graphBuilder.NewNode().ID())
+		vertex := NewDOTVertex(node)
 		uidToVertex[node.identity.UID] = vertex
-		graphBuilder.AddNode(vertex)
+		nodes = append(nodes, vertex)
 	}
 	for _, node := range uidToNode {
 		currVertex := uidToVertex[node.identity.UID]
 		for _, ownerRef := range node.owners {
 			currOwnerVertex, ok := uidToVertex[ownerRef.UID]
 			if !ok {
-				currOwnerVertex = NewMissingGonumVertex(ownerRef, graphBuilder.NewNode().ID())
+				currOwnerVertex = NewMissingdotVertex(ownerRef)
 				uidToVertex[node.identity.UID] = currOwnerVertex
-				graphBuilder.AddNode(currOwnerVertex)
+				nodes = append(nodes, currOwnerVertex)
 			}
-			graphBuilder.SetEdge(simple.Edge{
+			edges = append(edges, dotEdge{F: currVertex.uid, T: currOwnerVertex.uid})
-				F: currVertex,
-				T: currOwnerVertex,
-			})
-
 		}
 	}
 
-	return graphBuilder
+	sort.SliceStable(nodes, func(i, j int) bool { return nodes[i].uid < nodes[j].uid })
+	sort.SliceStable(edges, func(i, j int) bool {
+		if edges[i].F != edges[j].F {
+			return edges[i].F < edges[j].F
+		}
+		return edges[i].T < edges[j].T
+	})
+
+	return nodes, edges
 }
 
-func (m *concurrentUIDToNode) ToGonumGraphForObj(uids ...types.UID) graph.Directed {
+func (m *concurrentUIDToNode) ToDOTNodesAndEdgesForObj(uids ...types.UID) ([]*dotVertex, []dotEdge) {
 	m.uidToNodeLock.Lock()
 	defer m.uidToNodeLock.Unlock()
 
-	return toGonumGraphForObj(m.uidToNode, uids...)
+	return toDOTNodesAndEdgesForObj(m.uidToNode, uids...)
 }
 
-func toGonumGraphForObj(uidToNode map[types.UID]*node, uids ...types.UID) graph.Directed {
+func toDOTNodesAndEdgesForObj(uidToNode map[types.UID]*node, uids ...types.UID) ([]*dotVertex, []dotEdge) {
 	uidsToCheck := append([]types.UID{}, uids...)
 	interestingNodes := map[types.UID]*node{}
 
@@ -241,7 +269,7 @@ func toGonumGraphForObj(uidToNode map[types.UID]*node, uids ...types.UID) graph.
 		}
 	}
 
-	return toGonumGraph(interestingNodes)
+	return toDOTNodesAndEdges(interestingNodes)
 }
 
 // NewDebugHandler creates a new debugHTTPHandler.
@@ -253,32 +281,64 @@ type debugHTTPHandler struct {
 	controller *GarbageCollector
 }
 
+func marshalDOT(w io.Writer, nodes []*dotVertex, edges []dotEdge) error {
+	if _, err := w.Write([]byte("strict digraph full {\n")); err != nil {
+		return err
+	}
+	if len(nodes) > 0 {
+		if _, err := w.Write([]byte("  // Node definitions.\n")); err != nil {
+			return err
+		}
+		for _, node := range nodes {
+			if err := node.MarshalDOT(w); err != nil {
+				return err
+			}
+		}
+	}
+	if len(edges) > 0 {
+		if _, err := w.Write([]byte("  // Edge definitions.\n")); err != nil {
+			return err
+		}
+		for _, edge := range edges {
+			if err := edge.MarshalDOT(w); err != nil {
+				return err
+			}
+		}
+	}
+	if _, err := w.Write([]byte("}\n")); err != nil {
+		return err
+	}
+	return nil
+}
+
 func (h *debugHTTPHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 	if req.URL.Path != "/graph" {
 		http.Error(w, "", http.StatusNotFound)
 		return
 	}
 
-	var graph graph.Directed
+	var nodes []*dotVertex
+	var edges []dotEdge
 	if uidStrings := req.URL.Query()["uid"]; len(uidStrings) > 0 {
 		uids := []types.UID{}
 		for _, uidString := range uidStrings {
 			uids = append(uids, types.UID(uidString))
 		}
-		graph = h.controller.dependencyGraphBuilder.uidToNode.ToGonumGraphForObj(uids...)
+		nodes, edges = h.controller.dependencyGraphBuilder.uidToNode.ToDOTNodesAndEdgesForObj(uids...)
 
 	} else {
-		graph = h.controller.dependencyGraphBuilder.uidToNode.ToGonumGraph()
+		nodes, edges = h.controller.dependencyGraphBuilder.uidToNode.ToDOTNodesAndEdges()
 	}
 
-	data, err := dot.Marshal(graph, "full", "", "  ")
+	b := bytes.NewBuffer(nil)
-	if err != nil {
+	if err := marshalDOT(b, nodes, edges); err != nil {
 		http.Error(w, err.Error(), http.StatusInternalServerError)
 		return
 	}
+
 	w.Header().Set("Content-Type", "text/vnd.graphviz")
 	w.Header().Set("X-Content-Type-Options", "nosniff")
-	w.Write(data)
+	w.Write(b.Bytes())
 	w.WriteHeader(http.StatusOK)
 }
 

pkg/controller/garbagecollector/dump_test.go

@@ -17,12 +17,13 @@ limitations under the License.
 package garbagecollector
 
 import (
-	"sort"
+	"bytes"
+	"os"
+	"path/filepath"
 	"testing"
 
 	"github.com/davecgh/go-spew/spew"
-	"gonum.org/v1/gonum/graph"
+	"github.com/google/go-cmp/cmp"
-	"gonum.org/v1/gonum/graph/simple"
 
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/types"
@@ -116,11 +117,12 @@ var (
 	}
 )
 
-func TestToGonumGraph(t *testing.T) {
+func TestToDOTGraph(t *testing.T) {
 	tests := []struct {
-		name      string
+		name        string
-		uidToNode map[types.UID]*node
+		uidToNode   map[types.UID]*node
-		expect    graph.Directed
+		expectNodes []*dotVertex
+		expectEdges []dotEdge
 	}{
 		{
 			name: "simple",
@@ -129,24 +131,15 @@ func TestToGonumGraph(t *testing.T) {
 				types.UID("bravo"):   bravoNode(),
 				types.UID("charlie"): charlieNode(),
 			},
-			expect: func() graph.Directed {
+			expectNodes: []*dotVertex{
-				graphBuilder := simple.NewDirectedGraph()
+				NewDOTVertex(alphaNode()),
-				alphaVertex := NewGonumVertex(alphaNode(), graphBuilder.NewNode().ID())
+				NewDOTVertex(bravoNode()),
-				graphBuilder.AddNode(alphaVertex)
+				NewDOTVertex(charlieNode()),
-				bravoVertex := NewGonumVertex(bravoNode(), graphBuilder.NewNode().ID())
+			},
-				graphBuilder.AddNode(bravoVertex)
+			expectEdges: []dotEdge{
-				charlieVertex := NewGonumVertex(charlieNode(), graphBuilder.NewNode().ID())
+				{F: types.UID("alpha"), T: types.UID("bravo")},
-				graphBuilder.AddNode(charlieVertex)
+				{F: types.UID("alpha"), T: types.UID("charlie")},
-				graphBuilder.SetEdge(simple.Edge{
+			},
-					F: alphaVertex,
-					T: bravoVertex,
-				})
-				graphBuilder.SetEdge(simple.Edge{
-					F: alphaVertex,
-					T: charlieVertex,
-				})
-				return graphBuilder
-			}(),
 		},
 		{
 			name: "missing", // synthetic vertex created
@@ -154,24 +147,15 @@ func TestToGonumGraph(t *testing.T) {
 				types.UID("alpha"):   alphaNode(),
 				types.UID("charlie"): charlieNode(),
 			},
-			expect: func() graph.Directed {
+			expectNodes: []*dotVertex{
-				graphBuilder := simple.NewDirectedGraph()
+				NewDOTVertex(alphaNode()),
-				alphaVertex := NewGonumVertex(alphaNode(), graphBuilder.NewNode().ID())
+				NewDOTVertex(bravoNode()),
-				graphBuilder.AddNode(alphaVertex)
+				NewDOTVertex(charlieNode()),
-				bravoVertex := NewGonumVertex(bravoNode(), graphBuilder.NewNode().ID())
+			},
-				graphBuilder.AddNode(bravoVertex)
+			expectEdges: []dotEdge{
-				charlieVertex := NewGonumVertex(charlieNode(), graphBuilder.NewNode().ID())
+				{F: types.UID("alpha"), T: types.UID("bravo")},
-				graphBuilder.AddNode(charlieVertex)
+				{F: types.UID("alpha"), T: types.UID("charlie")},
-				graphBuilder.SetEdge(simple.Edge{
+			},
-					F: alphaVertex,
-					T: bravoVertex,
-				})
-				graphBuilder.SetEdge(simple.Edge{
-					F: alphaVertex,
-					T: charlieVertex,
-				})
-				return graphBuilder
-			}(),
 		},
 		{
 			name: "drop-no-ref",
@@ -181,24 +165,15 @@ func TestToGonumGraph(t *testing.T) {
 				types.UID("charlie"): charlieNode(),
 				types.UID("echo"):    echoNode(),
 			},
-			expect: func() graph.Directed {
+			expectNodes: []*dotVertex{
-				graphBuilder := simple.NewDirectedGraph()
+				NewDOTVertex(alphaNode()),
-				alphaVertex := NewGonumVertex(alphaNode(), graphBuilder.NewNode().ID())
+				NewDOTVertex(bravoNode()),
-				graphBuilder.AddNode(alphaVertex)
+				NewDOTVertex(charlieNode()),
-				bravoVertex := NewGonumVertex(bravoNode(), graphBuilder.NewNode().ID())
+			},
-				graphBuilder.AddNode(bravoVertex)
+			expectEdges: []dotEdge{
-				charlieVertex := NewGonumVertex(charlieNode(), graphBuilder.NewNode().ID())
+				{F: types.UID("alpha"), T: types.UID("bravo")},
-				graphBuilder.AddNode(charlieVertex)
+				{F: types.UID("alpha"), T: types.UID("charlie")},
-				graphBuilder.SetEdge(simple.Edge{
+			},
-					F: alphaVertex,
-					T: bravoVertex,
-				})
-				graphBuilder.SetEdge(simple.Edge{
-					F: alphaVertex,
-					T: charlieVertex,
-				})
-				return graphBuilder
-			}(),
 		},
 		{
 			name: "two-chains",
@@ -210,59 +185,38 @@ func TestToGonumGraph(t *testing.T) {
 				types.UID("foxtrot"): foxtrotNode(),
 				types.UID("golf"):    golfNode(),
 			},
-			expect: func() graph.Directed {
+			expectNodes: []*dotVertex{
-				graphBuilder := simple.NewDirectedGraph()
+				NewDOTVertex(alphaNode()),
-				alphaVertex := NewGonumVertex(alphaNode(), graphBuilder.NewNode().ID())
+				NewDOTVertex(bravoNode()),
-				graphBuilder.AddNode(alphaVertex)
+				NewDOTVertex(charlieNode()),
-				bravoVertex := NewGonumVertex(bravoNode(), graphBuilder.NewNode().ID())
+				NewDOTVertex(deltaNode()),
-				graphBuilder.AddNode(bravoVertex)
+				NewDOTVertex(foxtrotNode()),
-				charlieVertex := NewGonumVertex(charlieNode(), graphBuilder.NewNode().ID())
+				NewDOTVertex(golfNode()),
-				graphBuilder.AddNode(charlieVertex)
+			},
-				graphBuilder.SetEdge(simple.Edge{
+			expectEdges: []dotEdge{
-					F: alphaVertex,
+				{F: types.UID("alpha"), T: types.UID("bravo")},
-					T: bravoVertex,
+				{F: types.UID("alpha"), T: types.UID("charlie")},
-				})
+				{F: types.UID("delta"), T: types.UID("foxtrot")},
-				graphBuilder.SetEdge(simple.Edge{
+				{F: types.UID("foxtrot"), T: types.UID("golf")},
-					F: alphaVertex,
+			},
-					T: charlieVertex,
-				})
-
-				deltaVertex := NewGonumVertex(deltaNode(), graphBuilder.NewNode().ID())
-				graphBuilder.AddNode(deltaVertex)
-				foxtrotVertex := NewGonumVertex(foxtrotNode(), graphBuilder.NewNode().ID())
-				graphBuilder.AddNode(foxtrotVertex)
-				golfVertex := NewGonumVertex(golfNode(), graphBuilder.NewNode().ID())
-				graphBuilder.AddNode(golfVertex)
-				graphBuilder.SetEdge(simple.Edge{
-					F: deltaVertex,
-					T: foxtrotVertex,
-				})
-				graphBuilder.SetEdge(simple.Edge{
-					F: foxtrotVertex,
-					T: golfVertex,
-				})
-
-				return graphBuilder
-			}(),
 		},
 	}
 
 	for _, test := range tests {
 		t.Run(test.name, func(t *testing.T) {
-			actual := toGonumGraph(test.uidToNode)
+			actualNodes, actualEdges := toDOTNodesAndEdges(test.uidToNode)
-
+			compareGraphs(test.expectNodes, actualNodes, test.expectEdges, actualEdges, t)
-			compareGraphs(test.expect, actual, t)
 		})
 	}
-
 }
 
-func TestToGonumGraphObj(t *testing.T) {
+func TestToDOTGraphObj(t *testing.T) {
 	tests := []struct {
-		name      string
+		name        string
-		uidToNode map[types.UID]*node
+		uidToNode   map[types.UID]*node
-		uids      []types.UID
+		uids        []types.UID
-		expect    graph.Directed
+		expectNodes []*dotVertex
+		expectEdges []dotEdge
 	}{
 		{
 			name: "simple",
@@ -272,24 +226,15 @@ func TestToGonumGraphObj(t *testing.T) {
 				types.UID("charlie"): charlieNode(),
 			},
 			uids: []types.UID{types.UID("bravo")},
-			expect: func() graph.Directed {
+			expectNodes: []*dotVertex{
-				graphBuilder := simple.NewDirectedGraph()
+				NewDOTVertex(alphaNode()),
-				alphaVertex := NewGonumVertex(alphaNode(), graphBuilder.NewNode().ID())
+				NewDOTVertex(bravoNode()),
-				graphBuilder.AddNode(alphaVertex)
+				NewDOTVertex(charlieNode()),
-				bravoVertex := NewGonumVertex(bravoNode(), graphBuilder.NewNode().ID())
+			},
-				graphBuilder.AddNode(bravoVertex)
+			expectEdges: []dotEdge{
-				charlieVertex := NewGonumVertex(charlieNode(), graphBuilder.NewNode().ID())
+				{F: types.UID("alpha"), T: types.UID("bravo")},
-				graphBuilder.AddNode(charlieVertex)
+				{F: types.UID("alpha"), T: types.UID("charlie")},
-				graphBuilder.SetEdge(simple.Edge{
+			},
-					F: alphaVertex,
-					T: bravoVertex,
-				})
-				graphBuilder.SetEdge(simple.Edge{
-					F: alphaVertex,
-					T: charlieVertex,
-				})
-				return graphBuilder
-			}(),
 		},
 		{
 			name: "missing", // synthetic vertex created
@@ -297,11 +242,9 @@ func TestToGonumGraphObj(t *testing.T) {
 				types.UID("alpha"):   alphaNode(),
 				types.UID("charlie"): charlieNode(),
 			},
-			uids: []types.UID{types.UID("bravo")},
+			uids:        []types.UID{types.UID("bravo")},
-			expect: func() graph.Directed {
+			expectNodes: []*dotVertex{},
-				graphBuilder := simple.NewDirectedGraph()
+			expectEdges: []dotEdge{},
-				return graphBuilder
-			}(),
 		},
 		{
 			name: "drop-no-ref",
@@ -311,11 +254,9 @@ func TestToGonumGraphObj(t *testing.T) {
 				types.UID("charlie"): charlieNode(),
 				types.UID("echo"):    echoNode(),
 			},
-			uids: []types.UID{types.UID("echo")},
+			uids:        []types.UID{types.UID("echo")},
-			expect: func() graph.Directed {
+			expectNodes: []*dotVertex{},
-				graphBuilder := simple.NewDirectedGraph()
+			expectEdges: []dotEdge{},
-				return graphBuilder
-			}(),
 		},
 		{
 			name: "two-chains-from-owner",
@@ -328,25 +269,15 @@ func TestToGonumGraphObj(t *testing.T) {
 				types.UID("golf"):    golfNode(),
 			},
 			uids: []types.UID{types.UID("golf")},
-			expect: func() graph.Directed {
+			expectNodes: []*dotVertex{
-				graphBuilder := simple.NewDirectedGraph()
+				NewDOTVertex(deltaNode()),
-				deltaVertex := NewGonumVertex(deltaNode(), graphBuilder.NewNode().ID())
+				NewDOTVertex(foxtrotNode()),
-				graphBuilder.AddNode(deltaVertex)
+				NewDOTVertex(golfNode()),
-				foxtrotVertex := NewGonumVertex(foxtrotNode(), graphBuilder.NewNode().ID())
+			},
-				graphBuilder.AddNode(foxtrotVertex)
+			expectEdges: []dotEdge{
-				golfVertex := NewGonumVertex(golfNode(), graphBuilder.NewNode().ID())
+				{F: types.UID("delta"), T: types.UID("foxtrot")},
-				graphBuilder.AddNode(golfVertex)
+				{F: types.UID("foxtrot"), T: types.UID("golf")},
-				graphBuilder.SetEdge(simple.Edge{
+			},
-					F: deltaVertex,
-					T: foxtrotVertex,
-				})
-				graphBuilder.SetEdge(simple.Edge{
-					F: foxtrotVertex,
-					T: golfVertex,
-				})
-
-				return graphBuilder
-			}(),
 		},
 		{
 			name: "two-chains-from-child",
@@ -359,25 +290,15 @@ func TestToGonumGraphObj(t *testing.T) {
 				types.UID("golf"):    golfNode(),
 			},
 			uids: []types.UID{types.UID("delta")},
-			expect: func() graph.Directed {
+			expectNodes: []*dotVertex{
-				graphBuilder := simple.NewDirectedGraph()
+				NewDOTVertex(deltaNode()),
-				deltaVertex := NewGonumVertex(deltaNode(), graphBuilder.NewNode().ID())
+				NewDOTVertex(foxtrotNode()),
-				graphBuilder.AddNode(deltaVertex)
+				NewDOTVertex(golfNode()),
-				foxtrotVertex := NewGonumVertex(foxtrotNode(), graphBuilder.NewNode().ID())
+			},
-				graphBuilder.AddNode(foxtrotVertex)
+			expectEdges: []dotEdge{
-				golfVertex := NewGonumVertex(golfNode(), graphBuilder.NewNode().ID())
+				{F: types.UID("delta"), T: types.UID("foxtrot")},
-				graphBuilder.AddNode(golfVertex)
+				{F: types.UID("foxtrot"), T: types.UID("golf")},
-				graphBuilder.SetEdge(simple.Edge{
+			},
-					F: deltaVertex,
-					T: foxtrotVertex,
-				})
-				graphBuilder.SetEdge(simple.Edge{
-					F: foxtrotVertex,
-					T: golfVertex,
-				})
-
-				return graphBuilder
-			}(),
 		},
 		{
 			name: "two-chains-choose-both",
@@ -390,98 +311,125 @@ func TestToGonumGraphObj(t *testing.T) {
 				types.UID("golf"):    golfNode(),
 			},
 			uids: []types.UID{types.UID("delta"), types.UID("charlie")},
-			expect: func() graph.Directed {
+			expectNodes: []*dotVertex{
-				graphBuilder := simple.NewDirectedGraph()
+				NewDOTVertex(alphaNode()),
-				alphaVertex := NewGonumVertex(alphaNode(), graphBuilder.NewNode().ID())
+				NewDOTVertex(bravoNode()),
-				graphBuilder.AddNode(alphaVertex)
+				NewDOTVertex(charlieNode()),
-				bravoVertex := NewGonumVertex(bravoNode(), graphBuilder.NewNode().ID())
+				NewDOTVertex(deltaNode()),
-				graphBuilder.AddNode(bravoVertex)
+				NewDOTVertex(foxtrotNode()),
-				charlieVertex := NewGonumVertex(charlieNode(), graphBuilder.NewNode().ID())
+				NewDOTVertex(golfNode()),
-				graphBuilder.AddNode(charlieVertex)
+			},
-				graphBuilder.SetEdge(simple.Edge{
+			expectEdges: []dotEdge{
-					F: alphaVertex,
+				{F: types.UID("alpha"), T: types.UID("bravo")},
-					T: bravoVertex,
+				{F: types.UID("alpha"), T: types.UID("charlie")},
-				})
+				{F: types.UID("delta"), T: types.UID("foxtrot")},
-				graphBuilder.SetEdge(simple.Edge{
+				{F: types.UID("foxtrot"), T: types.UID("golf")},
-					F: alphaVertex,
+			},
-					T: charlieVertex,
-				})
-
-				deltaVertex := NewGonumVertex(deltaNode(), graphBuilder.NewNode().ID())
-				graphBuilder.AddNode(deltaVertex)
-				foxtrotVertex := NewGonumVertex(foxtrotNode(), graphBuilder.NewNode().ID())
-				graphBuilder.AddNode(foxtrotVertex)
-				golfVertex := NewGonumVertex(golfNode(), graphBuilder.NewNode().ID())
-				graphBuilder.AddNode(golfVertex)
-				graphBuilder.SetEdge(simple.Edge{
-					F: deltaVertex,
-					T: foxtrotVertex,
-				})
-				graphBuilder.SetEdge(simple.Edge{
-					F: foxtrotVertex,
-					T: golfVertex,
-				})
-
-				return graphBuilder
-			}(),
 		},
 	}
 
 	for _, test := range tests {
 		t.Run(test.name, func(t *testing.T) {
-			actual := toGonumGraphForObj(test.uidToNode, test.uids...)
+			actualNodes, actualEdges := toDOTNodesAndEdgesForObj(test.uidToNode, test.uids...)
-
+			compareGraphs(test.expectNodes, actualNodes, test.expectEdges, actualEdges, t)
-			compareGraphs(test.expect, actual, t)
 		})
 	}
 }
 
-func compareGraphs(expected, actual graph.Directed, t *testing.T) {
+func compareGraphs(expectedNodes, actualNodes []*dotVertex, expectedEdges, actualEdges []dotEdge, t *testing.T) {
-	// sort the edges by from ID, then to ID
-	// (the slices we get back are from map iteration, where order is not guaranteed)
-	expectedNodes := expected.Nodes().(graph.NodeSlicer).NodeSlice()
-	actualNodes := actual.Nodes().(graph.NodeSlicer).NodeSlice()
-	sort.Sort(gonumByUID(expectedNodes))
-	sort.Sort(gonumByUID(actualNodes))
-
 	if len(expectedNodes) != len(actualNodes) {
-		t.Fatal(spew.Sdump(actual))
+		t.Fatal(spew.Sdump(actualNodes))
 	}
-
 	for i := range expectedNodes {
-		currExpected := *expectedNodes[i].(*gonumVertex)
+		currExpected := expectedNodes[i]
-		currActual := *actualNodes[i].(*gonumVertex)
+		currActual := actualNodes[i]
 		if currExpected.uid != currActual.uid {
 			t.Errorf("expected %v, got %v", spew.Sdump(currExpected), spew.Sdump(currActual))
 		}
-
+	}
-		expectedFrom := append([]graph.Node{}, expected.From(expectedNodes[i].ID()).(graph.NodeSlicer).NodeSlice()...)
+	if len(expectedEdges) != len(actualEdges) {
-		actualFrom := append([]graph.Node{}, actual.From(actualNodes[i].ID()).(graph.NodeSlicer).NodeSlice()...)
+		t.Fatal(spew.Sdump(actualEdges))
-		sort.Sort(gonumByUID(expectedFrom))
+	}
-		sort.Sort(gonumByUID(actualFrom))
+	for i := range expectedEdges {
-		if len(expectedFrom) != len(actualFrom) {
+		currExpected := expectedEdges[i]
-			t.Errorf("%q: expected %v, got %v", currExpected.uid, spew.Sdump(expectedFrom), spew.Sdump(actualFrom))
+		currActual := actualEdges[i]
-		}
+		if currExpected != currActual {
-		for i := range expectedFrom {
+			t.Errorf("expected %v, got %v", spew.Sdump(currExpected), spew.Sdump(currActual))
-			currExpectedFrom := *expectedFrom[i].(*gonumVertex)
-			currActualFrom := *actualFrom[i].(*gonumVertex)
-			if currExpectedFrom.uid != currActualFrom.uid {
-				t.Errorf("expected %v, got %v", spew.Sdump(currExpectedFrom), spew.Sdump(currActualFrom))
-			}
 		}
 	}
 }
 
-type gonumByUID []graph.Node
+func TestMarshalDOT(t *testing.T) {
+	ref1 := objectReference{
+		OwnerReference: metav1.OwnerReference{
+			UID:        types.UID("ref1-[]\"\\Iñtërnâtiônàlizætiøn,🐹"),
+			Name:       "ref1name-Iñtërnâtiônàlizætiøn,🐹",
+			Kind:       "ref1kind-Iñtërnâtiônàlizætiøn,🐹",
+			APIVersion: "ref1group/version",
+		},
+		Namespace: "ref1ns",
+	}
+	ref2 := objectReference{
+		OwnerReference: metav1.OwnerReference{
+			UID:        types.UID("ref2-"),
+			Name:       "ref2name-",
+			Kind:       "ref2kind-",
+			APIVersion: "ref2group/version",
+		},
+		Namespace: "ref2ns",
+	}
+	testcases := []struct {
+		file  string
+		nodes []*dotVertex
+		edges []dotEdge
+	}{
+		{
+			file: "empty.dot",
+		},
+		{
+			file: "simple.dot",
+			nodes: []*dotVertex{
+				NewDOTVertex(alphaNode()),
+				NewDOTVertex(bravoNode()),
+				NewDOTVertex(charlieNode()),
+				NewDOTVertex(deltaNode()),
+				NewDOTVertex(foxtrotNode()),
+				NewDOTVertex(golfNode()),
+			},
+			edges: []dotEdge{
+				{F: types.UID("alpha"), T: types.UID("bravo")},
+				{F: types.UID("alpha"), T: types.UID("charlie")},
+				{F: types.UID("delta"), T: types.UID("foxtrot")},
+				{F: types.UID("foxtrot"), T: types.UID("golf")},
+			},
+		},
+		{
+			file: "escaping.dot",
+			nodes: []*dotVertex{
+				NewDOTVertex(makeNode(ref1, withOwners(ref2))),
+				NewDOTVertex(makeNode(ref2)),
+			},
+			edges: []dotEdge{
+				{F: types.UID(ref1.UID), T: types.UID(ref2.UID)},
+			},
+		},
+	}
 
-func (s gonumByUID) Len() int      { return len(s) }
+	for _, tc := range testcases {
-func (s gonumByUID) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
+		t.Run(tc.file, func(t *testing.T) {
+			goldenData, err := os.ReadFile(filepath.Join("testdata", tc.file))
+			if err != nil {
+				t.Fatal(err)
+			}
+			b := bytes.NewBuffer(nil)
+			if err := marshalDOT(b, tc.nodes, tc.edges); err != nil {
+				t.Fatal(err)
+			}
 
-func (s gonumByUID) Less(i, j int) bool {
+			if e, a := string(goldenData), string(b.Bytes()); cmp.Diff(e, a) != "" {
-	lhs := s[i].(*gonumVertex)
+				t.Logf("got\n%s", string(a))
-	lhsUID := string(lhs.uid)
+				t.Fatalf("unexpected diff:\n%s", cmp.Diff(e, a))
-	rhs := s[j].(*gonumVertex)
+			}
-	rhsUID := string(rhs.uid)
+		})
-
+	}
-	return lhsUID < rhsUID
 }

pkg/controller/garbagecollector/testdata/empty.dot

@@ -0,0 +1,2 @@
+strict digraph full {
+}

pkg/controller/garbagecollector/testdata/escaping.dot

@@ -0,0 +1,31 @@
+strict digraph full {
+  // Node definitions.
+  "ref1-[]\"\\Iñtërnâtiônàlizætiøn,🐹" [
+    label="uid=ref1-[]\"\\Iñtërnâtiônàlizætiøn,🐹\nnamespace=ref1ns\nref1kind-Iñtërnâtiônàlizætiøn,🐹.version.ref1group/ref1name-Iñtërnâtiônàlizætiøn,🐹\n"
+    group="ref1group"
+    version="version"
+    kind="ref1kind-Iñtërnâtiônàlizætiøn,🐹"
+    namespace="ref1ns"
+    name="ref1name-Iñtërnâtiônàlizætiøn,🐹"
+    uid="ref1-[]\"\\Iñtërnâtiônàlizætiøn,🐹"
+    missing="false"
+    beingDeleted="false"
+    deletingDependents="false"
+    virtual="false"
+  ];
+  "ref2-" [
+    label="uid=ref2-\nnamespace=ref2ns\nref2kind-.version.ref2group/ref2name-\n"
+    group="ref2group"
+    version="version"
+    kind="ref2kind-"
+    namespace="ref2ns"
+    name="ref2name-"
+    uid="ref2-"
+    missing="false"
+    beingDeleted="false"
+    deletingDependents="false"
+    virtual="false"
+  ];
+  // Edge definitions.
+  "ref1-[]\"\\Iñtërnâtiônàlizætiøn,🐹" -> "ref2-";
+}

pkg/controller/garbagecollector/testdata/simple.dot

@@ -0,0 +1,86 @@
+strict digraph full {
+  // Node definitions.
+  "alpha" [
+    label="uid=alpha\nnamespace=\n./\n"
+    group=""
+    version=""
+    kind=""
+    namespace=""
+    name=""
+    uid="alpha"
+    missing="false"
+    beingDeleted="false"
+    deletingDependents="false"
+    virtual="false"
+  ];
+  "bravo" [
+    label="uid=bravo\nnamespace=\n./\n"
+    group=""
+    version=""
+    kind=""
+    namespace=""
+    name=""
+    uid="bravo"
+    missing="false"
+    beingDeleted="false"
+    deletingDependents="false"
+    virtual="false"
+  ];
+  "charlie" [
+    label="uid=charlie\nnamespace=\n./\n"
+    group=""
+    version=""
+    kind=""
+    namespace=""
+    name=""
+    uid="charlie"
+    missing="false"
+    beingDeleted="false"
+    deletingDependents="false"
+    virtual="false"
+  ];
+  "delta" [
+    label="uid=delta\nnamespace=\n./\n"
+    group=""
+    version=""
+    kind=""
+    namespace=""
+    name=""
+    uid="delta"
+    missing="false"
+    beingDeleted="false"
+    deletingDependents="false"
+    virtual="false"
+  ];
+  "foxtrot" [
+    label="uid=foxtrot\nnamespace=\n./\n"
+    group=""
+    version=""
+    kind=""
+    namespace=""
+    name=""
+    uid="foxtrot"
+    missing="false"
+    beingDeleted="false"
+    deletingDependents="false"
+    virtual="false"
+  ];
+  "golf" [
+    label="uid=golf\nnamespace=\n./\n"
+    group=""
+    version=""
+    kind=""
+    namespace=""
+    name=""
+    uid="golf"
+    missing="false"
+    beingDeleted="false"
+    deletingDependents="false"
+    virtual="false"
+  ];
+  // Edge definitions.
+  "alpha" -> "bravo";
+  "alpha" -> "charlie";
+  "delta" -> "foxtrot";
+  "foxtrot" -> "golf";
+}