func UnregisterFromEtcd() {
_, err := kAPI.Delete(context.Background(), myKey, nil)
if err != nil {
log.Println(err.Error())
log.Println("Cannot unregister from etcd")
}
}
func InitializeEtcd(uri string) error {
cfg := client.Config{
Endpoints: []string{uri},
}
etcd, err := client.New(cfg)
if err != nil {
return err
}
kAPI = client.NewKeysAPI(etcd)
//This is needed to probe if the etcd server is reachable
_, err = kAPI.Set(
context.Background(),
"/probe",
"etcd",
&client.SetOptions{TTL: time.Duration(1) * time.Millisecond},
)
if err != nil {
log.Println(err)
return err
}
return nil
}
func RegisterToEtcd(name string, address string) error {
var err error
uuid, err = generateUUID()
if err != nil {
log.Println(err)
return err
}
myKey = "mu-sim/" + name + "/" + uuid
myAddress = address
_, err = kAPI.Set(
context.Background(),
myKey,
myAddress,
&client.SetOptions{TTL: time.Duration(5) * time.Second},
)
if err != nil {
log.Println(err)
return err
}
return nil
}
func GetAvailableInstances(service string) ([]string, error) {
key := "mu-sim/" + service + "/"
available := []string{}
resp, err := kAPI.Get(context.Background(), key, nil)
if err != nil {
log.Println(err)
return []string{}, err
}
for _, n := range resp.Node.Nodes {
available = append(available, n.Value)
}
if len(available) < 1 {
log.Println(ErrNoDestinations)
return []string{}, ErrNoDestinations
}
return available, nil
}
func KeepAlive(ch_stop chan struct{}) {
var err error
ticker := time.NewTicker(time.Duration(5) * time.Second)
for {
select {
case <-ticker.C:
_, err = kAPI.Set(
context.Background(),
myKey,
myAddress,
&client.SetOptions{TTL: time.Duration(5) * time.Second},
)
if err != nil {
log.Println(err)
log.Println("Cannot keep the agent Alive")
}
case <-ch_stop:
return
}
}
}