Make NetworkStats a pointer to help the callers ignore that stats if it cannot be returned for any reason.

Docker-DCO-1.1-Signed-off-by: Vishnu Kannan <vishnuk@google.com> (github: vishh)

network/stats.go

@@ -20,17 +20,17 @@ type NetworkStats struct {
 }
 
 // Returns the network statistics for the network interfaces represented by the NetworkRuntimeInfo.
-func GetStats(networkState *NetworkState) (NetworkStats, error) {
+func GetStats(networkState *NetworkState) (*NetworkStats, error) {
 	// This can happen if the network runtime information is missing - possible if the container was created by an old version of libcontainer.
 	if networkState.VethHost == "" {
-		return NetworkStats{}, nil
+		return nil, nil
 	}
 	data, err := readSysfsNetworkStats(networkState.VethHost)
 	if err != nil {
-		return NetworkStats{}, err
+		return nil, err
 	}
 
-	return NetworkStats{
+	return &NetworkStats{
 		RxBytes:   data["rx_bytes"],
 		RxPackets: data["rx_packets"],
 		RxErrors:  data["rx_errors"],

types.go

@@ -6,6 +6,6 @@ import (
 )
 
 type ContainerStats struct {
-	NetworkStats network.NetworkStats `json:"network_stats, omitempty"`
-	CgroupStats  *cgroups.Stats       `json:"cgroup_stats, omitempty"`
+	NetworkStats *network.NetworkStats `json:"network_stats, omitempty"`
+	CgroupStats  *cgroups.Stats        `json:"cgroup_stats, omitempty"`
 }