Add containers by hostname view.

app/router.go

@@ -224,6 +224,15 @@ var topologyRegistry = &registry{
 				{"hide", "System containers hidden", true, render.FilterSystem},
 			}},
 		},
+		"containers-by-hostname": {
+			human:    "by hostname",
+			parent:   "containers",
+			renderer: render.ContainerHostnameRenderer,
+			options: optionParams{"system": {
+				{"show", "System containers shown", false, nop},
+				{"hide", "System containers hidden", true, render.FilterSystem},
+			}},
+		},
 		"hosts": {
 			human:    "Hosts",
 			parent:   "",

probe/docker/container.go

@@ -22,11 +22,12 @@ import (
 
 // These constants are keys used in node metadata
 const (
-	ContainerName    = "docker_container_name"
-	ContainerCommand = "docker_container_command"
-	ContainerPorts   = "docker_container_ports"
-	ContainerCreated = "docker_container_created"
-	ContainerIPs     = "docker_container_ips"
+	ContainerName     = "docker_container_name"
+	ContainerCommand  = "docker_container_command"
+	ContainerPorts    = "docker_container_ports"
+	ContainerCreated  = "docker_container_created"
+	ContainerIPs      = "docker_container_ips"
+	ContainerHostname = "docker_container_hostname"
 
 	NetworkRxDropped = "network_rx_dropped"
 	NetworkRxBytes   = "network_rx_bytes"
@@ -221,6 +222,7 @@ func (c *container) GetNode(localAddrs []net.IP) report.Node {
 		ImageID:          c.container.Image,
 		ContainerIPs: strings.Join(append(c.container.NetworkSettings.SecondaryIPAddresses,
 			c.container.NetworkSettings.IPAddress), " "),
+		ContainerHostname: c.container.Config.Hostname,
 	})
 	AddLabels(result, c.container.Config.Labels)
 

probe/docker/container_linux_test.go

@@ -80,7 +80,7 @@ func TestContainer(t *testing.T) {
 	test.Poll(t, 100*time.Millisecond, want, func() interface{} {
 		node := c.GetNode([]net.IP{})
 		for k, v := range node.Metadata {
-			if v == "0" {
+			if v == "0" || v == "" {
 				delete(node.Metadata, k)
 			}
 		}

render/mapping.go

@@ -594,6 +594,28 @@ func MapContainer2Pod(n RenderableNode, _ report.Networks) RenderableNodes {
 	return RenderableNodes{id: result}
 }
 
+// MapContainer2Hostname maps container RenderableNodes to 'hostname' renderabled nodes..
+func MapContainer2Hostname(n RenderableNode, _ report.Networks) RenderableNodes {
+	// Propogate all pseudo nodes
+	if n.Pseudo {
+		return RenderableNodes{n.ID: n}
+	}
+
+	// Otherwise, if some some reason the container doesn't have a hostname
+	// (maybe slightly out of sync reports), just drop it
+	id, ok := n.Node.Metadata[docker.ContainerHostname]
+	if !ok {
+		return RenderableNodes{}
+	}
+
+	// Add container-<id> key to NMD, which will later be counted to produce the minor label
+	result := NewDerivedNode(id, n)
+	result.LabelMajor = id
+	result.Rank = id
+	result.Node.Counters[containersKey] = 1
+	return RenderableNodes{id: result}
+}
+
 // MapCountContainers maps 1:1 container image nodes, counting
 // the number of containers grouped together and putting
 // that info in the minor label.

render/topologies.go

@@ -171,6 +171,25 @@ var ContainerImageRenderer = Map{
 	},
 }
 
+// ContainerHostnameRenderer is a Renderer which produces a renderable container
+// by hostname graph..
+var ContainerHostnameRenderer = Map{
+	MapFunc: MapCountContainers,
+	Renderer: Map{
+		MapFunc: MapContainer2Hostname,
+		Renderer: MakeReduce(
+			Map{
+				MapFunc:  MapContainer2ContainerImage,
+				Renderer: ContainerRenderer,
+			},
+			Map{
+				MapFunc:  MapContainerImageIdentity,
+				Renderer: SelectContainerImage,
+			},
+		),
+	},
+}
+
 // AddressRenderer is a Renderer which produces a renderable address
 // graph from the address topology.
 var AddressRenderer = Map{