Use a metadata key per docker label

probe/docker/container.go

@@ -10,6 +10,7 @@ import (
 	"net/http"
 	"net/http/httputil"
 	"net/url"
+	"sort"
 	"strconv"
 	"strings"
 	"sync"
@@ -22,12 +23,12 @@ 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"
-	ContainerLabels  = "docker_container_labels"
+	ContainerName        = "docker_container_name"
+	ContainerCommand     = "docker_container_command"
+	ContainerPorts       = "docker_container_ports"
+	ContainerCreated     = "docker_container_created"
+	ContainerIPs         = "docker_container_ips"
+	ContainerLabelPrefix = "docker_container_label_"
 
 	NetworkRxDropped = "network_rx_dropped"
 	NetworkRxBytes   = "network_rx_bytes"
@@ -207,7 +208,6 @@ func (c *container) GetNodeMetadata() report.NodeMetadata {
 	c.RLock()
 	defer c.RUnlock()
 
-	labels, _ := json.Marshal(c.container.Config.Labels)
 	result := report.MakeNodeMetadataWith(map[string]string{
 		ContainerID:      c.ID(),
 		ContainerName:    strings.TrimPrefix(c.container.Name, "/"),
@@ -217,9 +217,19 @@ func (c *container) GetNodeMetadata() report.NodeMetadata {
 		ImageID:          c.container.Image,
 		ContainerIPs: strings.Join(append(c.container.NetworkSettings.SecondaryIPAddresses,
 			c.container.NetworkSettings.IPAddress), " "),
-		ContainerLabels: string(labels),
 	})
 
+	// Add labels in alphabetical order
+	labels := c.container.Config.Labels
+	labelKeys := make([]string, 0, len(labels))
+	for k := range labels {
+		labelKeys = append(labelKeys, k)
+	}
+	sort.Strings(labelKeys)
+	for _, labelKey := range labelKeys {
+		result.Metadata[ContainerLabelPrefix+labelKey] = labels[labelKey]
+	}
+
 	if c.latestStats == nil {
 		return result
 	}
@@ -248,14 +258,19 @@ func (c *container) GetNodeMetadata() report.NodeMetadata {
 	return result
 }
 
-// ExtractContainerLabels returns the list of Docker container labels given a NodeMetadata from the Container topology.
-func ExtractContainerLabels(nmd report.NodeMetadata) map[string]string {
-	result := make(map[string]string)
-	json.Unmarshal([]byte(nmd.Metadata[ContainerLabels]), &result)
-	return result
-}
-
 // ExtractContainerIPs returns the list of container IPs given a NodeMetadata from the Container topology.
 func ExtractContainerIPs(nmd report.NodeMetadata) []string {
 	return strings.Fields(nmd.Metadata[ContainerIPs])
 }
+
+// ExtractContainerLabels returns the list of Docker container labels given a NodeMetadata from the Container topology.
+func ExtractContainerLabels(nmd report.NodeMetadata) map[string]string {
+	result := map[string]string{}
+	for key, value := range nmd.Metadata {
+		if strings.HasPrefix(key, ContainerLabelPrefix) {
+			label := key[len(ContainerLabelPrefix):]
+			result[label] = value
+		}
+	}
+	return result
+}

render/detailed_node.go

@@ -313,15 +313,8 @@ func containerOriginTable(nmd report.NodeMetadata, addHostTag bool) (Table, bool
 		rows = append(rows, Row{Key: "IP Address", ValueMajor: ip, ValueMinor: ""})
 	}
 
-	// Add labels in alphabetical order
-	labels := docker.ExtractContainerLabels(nmd)
-	labelKeys := make([]string, 0, len(labels))
-	for k := range labels {
-		labelKeys = append(labelKeys, k)
-	}
-	sort.Strings(labelKeys)
-	for _, key := range labelKeys {
-		rows = append(rows, Row{Key: fmt.Sprintf("Label %q", key), ValueMajor: labels[key]})
+	for labelKey, labelValue := range docker.ExtractContainerLabels(nmd) {
+		rows = append(rows, Row{Key: fmt.Sprintf("Label %q", labelKey), ValueMajor: labelValue})
 
 	}
 

test/report_fixture.go

@@ -174,11 +174,12 @@ var (
 					report.HostNodeID:    ClientHostNodeID,
 				}),
 				ServerContainerNodeID: report.MakeNodeMetadataWith(map[string]string{
-					docker.ContainerID:     ServerContainerID,
-					docker.ContainerName:   "server",
-					docker.ImageID:         ServerContainerImageID,
-					report.HostNodeID:      ServerHostNodeID,
-					docker.ContainerLabels: `{"foo1": "bar1", "foo2": "bar2"}`,
+					docker.ContainerID:                   ServerContainerID,
+					docker.ContainerName:                 "server",
+					docker.ImageID:                       ServerContainerImageID,
+					report.HostNodeID:                    ServerHostNodeID,
+					docker.ContainerLabelPrefix + "foo1": "bar1",
+					docker.ContainerLabelPrefix + "foo2": "bar2",
 				}),
 			},
 		},