report.Upgrade: reconstruct namespaces

Old probes do not report namespace topologies.
`report.upgradeNamespaces()` recontructs namespace topologies using the data available from other kubernetes resources.

Also, add a test.

report/report.go

@@ -42,6 +42,13 @@ const (
 
 	// Used when counting the number of containers
 	ContainersKey = "containers"
+
+	// The following constants are defined in github.com/weaveworks/scope/kubernetes,
+	// and are redefined to avoid import cycles.
+	KubernetesState        = "kubernetes_state"
+	KubernetesName         = "kubernetes_name"
+	KubernetesNamespace    = "kubernetes_namespace"
+	KubernetesStateDeleted = "delete"
 )
 
 // Report is the core data type. It's produced by probes, and consumed and
@@ -351,7 +358,7 @@ func (r Report) Validate() error {
 //
 // This for now creates node's LatestControls from Controls.
 func (r Report) Upgrade() Report {
-	return r.upgradeLatestControls().upgradePodNodes()
+	return r.upgradeLatestControls().upgradePodNodes().upgradeNamespaces()
 }
 
 func (r Report) upgradeLatestControls() Report {
@@ -419,6 +426,36 @@ func (r Report) upgradePodNodes() Report {
 	return r
 }
 
+func (r Report) upgradeNamespaces() Report {
+	if len(r.Namespace.Nodes) > 0 {
+		return r
+	}
+
+	namespaces := map[string]struct{}{}
+	for _, t := range []Topology{r.Pod, r.Service, r.Deployment, r.DaemonSet, r.StatefulSet, r.CronJob} {
+		for _, n := range t.Nodes {
+			if state, ok := n.Latest.Lookup(KubernetesState); ok && state == KubernetesStateDeleted {
+				continue
+			}
+			if namespace, ok := n.Latest.Lookup(KubernetesNamespace); ok {
+				namespaces[namespace] = struct{}{}
+			}
+		}
+	}
+
+	nodes := Nodes{}
+	for ns := range namespaces {
+		// Namespace ID
+		// Probes did not use to report namespace ids, but since creating a report node requires an id,
+		// the namespace name, which is unique, is passed to `MakeNamespaceNodeID
+		namespaceID := MakeNamespaceNodeID(ns)
+		nodes[namespaceID] = MakeNodeWith(namespaceID, map[string]string{KubernetesName: ns})
+	}
+	r.Namespace.Nodes = nodes
+
+	return r
+}
+
 // BackwardCompatible returns a new backward-compatible report.
 //
 // This for now creates node's Controls from LatestControls.

report/report_test.go

@@ -7,6 +7,7 @@ import (
 
 	"github.com/weaveworks/common/mtime"
 	"github.com/weaveworks/common/test"
+	"github.com/weaveworks/scope/probe/kubernetes"
 	"github.com/weaveworks/scope/report"
 	s_reflect "github.com/weaveworks/scope/test/reflect"
 )
@@ -106,8 +107,14 @@ func TestReportUpgrade(t *testing.T) {
 	mtime.NowForce(time.Now())
 	defer mtime.NowReset()
 	parentsWithDeployment := report.MakeSets().Add(report.Deployment, report.MakeStringSet("id"))
-	rsNode := report.MakeNode("bar").WithParents(parentsWithDeployment)
-	podNode := report.MakeNode("foo").WithControls("alive").WithParents(report.MakeSets().Add(report.ReplicaSet, report.MakeStringSet("bar")))
+	rsNode := report.MakeNode("bar").
+		WithParents(parentsWithDeployment)
+	namespaceName := "ns"
+	namespaceID := report.MakeNamespaceNodeID(namespaceName)
+	podNode := report.MakeNode("foo").
+		WithLatests(map[string]string{kubernetes.Namespace: namespaceName}).
+		WithControls("alive").
+		WithParents(report.MakeSets().Add(report.ReplicaSet, report.MakeStringSet("bar")))
 	controls := map[string]report.NodeControlData{
 		"alive": {
 			Dead: false,
@@ -117,9 +124,12 @@ func TestReportUpgrade(t *testing.T) {
 	rpt := report.MakeReport()
 	rpt.ReplicaSet.AddNode(rsNode)
 	rpt.Pod.AddNode(podNode)
+	namespaceNode := report.MakeNode(namespaceID).
+		WithLatests(map[string]string{kubernetes.Name: namespaceName})
 	expected := report.MakeReport()
 	expected.ReplicaSet.AddNode(rsNode)
 	expected.Pod.AddNode(expectedPodNode)
+	expected.Namespace.AddNode(namespaceNode)
 	got := rpt.Upgrade()
 	if !s_reflect.DeepEqual(expected, got) {
 		t.Error(test.Diff(expected, got))