Add 'latest' CRDT; use it to store container state.

Also use same technique to merge the controls, returning the latest
set of controls instead of the union.

probe/docker/container.go

@@ -264,12 +264,11 @@ func (c *container) GetNode(hostID string, localAddrs []net.IP) report.Node {
 		ContainerCommand:  c.container.Path + " " + strings.Join(c.container.Args, " "),
 		ImageID:           c.container.Image,
 		ContainerHostname: c.Hostname(),
-		ContainerState:    state,
 	}).WithSets(report.Sets{
 		ContainerPorts:         c.ports(localAddrs),
 		ContainerIPs:           report.MakeStringSet(ips...),
 		ContainerIPsWithScopes: report.MakeStringSet(ipsWithScopes...),
-	})
+	}).WithLatest(ContainerState, state)
 
 	if c.container.State.Paused {
 		result = result.WithControls(UnpauseContainer)
@@ -285,7 +284,7 @@ func (c *container) GetNode(hostID string, localAddrs []net.IP) report.Node {
 		return result
 	}
 
-	result = result.Merge(report.MakeNodeWith(map[string]string{
+	result = result.WithMetadata(map[string]string{
 		NetworkRxDropped: strconv.FormatUint(c.latestStats.Network.RxDropped, 10),
 		NetworkRxBytes:   strconv.FormatUint(c.latestStats.Network.RxBytes, 10),
 		NetworkRxErrors:  strconv.FormatUint(c.latestStats.Network.RxErrors, 10),
@@ -305,7 +304,8 @@ func (c *container) GetNode(hostID string, localAddrs []net.IP) report.Node {
 		CPUTotalUsage:        strconv.FormatUint(c.latestStats.CPUStats.CPUUsage.TotalUsage, 10),
 		CPUUsageInKernelmode: strconv.FormatUint(c.latestStats.CPUStats.CPUUsage.UsageInKernelmode, 10),
 		CPUSystemCPUUsage:    strconv.FormatUint(c.latestStats.CPUStats.SystemCPUUsage, 10),
-	}))
+	})
+
 	return result
 }
 

probe/docker/container_test.go

@@ -74,12 +74,14 @@ func TestContainer(t *testing.T) {
 		"docker_label_foo1":        "bar1",
 		"docker_label_foo2":        "bar2",
 		"memory_usage":             "12345",
-		"docker_container_state":   "running",
 	}).WithSets(report.Sets{
 		"docker_container_ports":           report.MakeStringSet("1.2.3.4:80->80/tcp", "81/tcp"),
 		"docker_container_ips":             report.MakeStringSet("1.2.3.4"),
 		"docker_container_ips_with_scopes": report.MakeStringSet("scope;1.2.3.4"),
-	}).WithControls(docker.RestartContainer, docker.StopContainer, docker.PauseContainer)
+	}).WithControls(
+		docker.RestartContainer, docker.StopContainer, docker.PauseContainer,
+	).WithLatest("docker_container_state", "running")
+
 	test.Poll(t, 100*time.Millisecond, want, func() interface{} {
 		node := c.GetNode("scope", []net.IP{})
 		for k, v := range node.Metadata {

probe/host/tagger.go

@@ -23,16 +23,16 @@ func NewTagger(hostID, probeID string) Tagger {
 
 // Tag implements Tagger.
 func (t Tagger) Tag(r report.Report) (report.Report, error) {
-	other := report.MakeNodeWith(map[string]string{
+	metadata := map[string]string{
 		report.HostNodeID: t.hostNodeID,
 		report.ProbeID:    t.probeID,
-	})
+	}
 
 	// Explicity don't tag Endpoints and Addresses - These topologies include pseudo nodes,
 	// and as such do their own host tagging
 	for _, topology := range []report.Topology{r.Process, r.Container, r.ContainerImage, r.Host, r.Overlay} {
-		for id := range topology.Nodes {
-			topology.AddNode(id, other)
+		for id, node := range topology.Nodes {
+			topology.AddNode(id, node.WithMetadata(metadata))
 		}
 	}
 	return r, nil

probe/tag_report.go

@@ -57,9 +57,9 @@ func (topologyTagger) Tag(r report.Report) (report.Report, error) {
 		"host":            &(r.Host),
 		"overlay":         &(r.Overlay),
 	} {
-		other := report.MakeNodeWith(map[string]string{Topology: val})
-		for id := range topology.Nodes {
-			topology.AddNode(id, other)
+		metadata := map[string]string{Topology: val}
+		for id, node := range topology.Nodes {
+			topology.AddNode(id, node.WithMetadata(metadata))
 		}
 	}
 	return r, nil

probe/tag_report_test.go

@@ -5,7 +5,6 @@ import (
 	"testing"
 
 	"github.com/weaveworks/scope/report"
-	"github.com/weaveworks/scope/test"
 )
 
 func TestApply(t *testing.T) {
@@ -38,11 +37,9 @@ func TestApply(t *testing.T) {
 func TestTagMissingID(t *testing.T) {
 	const nodeID = "not-found"
 	r := report.MakeReport()
-	want := report.MakeNode()
 	rpt, _ := newTopologyTagger().Tag(r)
-	have := rpt.Endpoint.Nodes[nodeID].Copy()
-	if !reflect.DeepEqual(want, have) {
-		t.Error(test.Diff(want, have))
+	_, ok := rpt.Endpoint.Nodes[nodeID]
+	if ok {
 		t.Error("TopologyTagger erroneously tagged a missing node ID")
 	}
 }