*: store sandbox IP

Don't call into net namespace on every status call

Signed-off-by: Antonio Murdaca <runcom@redhat.com>

libkpod/sandbox/sandbox.go

@@ -154,6 +154,8 @@ type Sandbox struct {
 	hostname       string
 	portMappings   []*hostport.PortMapping
 	stopped        bool
+	// ipv4 or ipv6 cache
+	ip string
 }
 
 const (
@@ -202,6 +204,16 @@ func New(id, namespace, name, kubeName, logDir string, labels, annotations map[s
 	return sb, nil
 }
 
+// AddIP stores the ip in the sandbox
+func (s *Sandbox) AddIP(ip string) {
+	s.ip = ip
+}
+
+// IP returns the ip of the sandbox
+func (s *Sandbox) IP() string {
+	return s.ip
+}
+
 // ID returns the id of the sandbox
 func (s *Sandbox) ID() string {
 	return s.id