finally i figure this out XD!
type obj struct {
Targets []string `json:"targets"`
Labels map[string]string `json:"labels"`
}
func main() {
// Creating simulation
var myobj = []*obj{}
n := new(obj)
n.Targets = append(n.Targets, "10.0.0.1")
n.Labels = make(map[string]string)
n.Labels["job"] = "db2"
myobj = append(myobj, n)
k := new(obj)
k.Targets = append(k.Targets, "192.168.1.12")
k.Targets = append(k.Targets, "192.168.1.13")
k.Labels = make(map[string]string)
k.Labels["job"] = "mysql"
myobj = append(myobj, k)
solved panic: runtime error: index out of range 1