func NewEtcdWatcher(baseKey string, urls ...string) Watcher {
client := etcd.NewClient(urls)
ew := etcdWatcher{
client: client,
baseKey: baseKey,
serviceChannel: make(chan ServiceUpdate),
listeners: make(map[string][]chan ServiceUpdate),
}
go util.Forever(func() { ew.watchEtcdForChanges(baseKey) }, time.Second)
go util.Forever(func() { ew.handleUpdates() }, time.Second)
return ew
}
// NewClient returns a new Client to handle requests to the
// service at the other end of the connection.
// A watcher is used to get updates about service endpoints
func NewClient(serviceName string, watcher watch.Watcher) *Client {
// Dial with no addresses means adding no endpoints
client, err := Dial()
if err != nil {
glog.Fatal(err)
}
// Handle updates about service endpoints
serviceChannel := make(chan watch.ServiceUpdate)
go util.Forever(func() {
serviceUpdate := <-serviceChannel
switch serviceUpdate.Op {
case watch.ADD:
if err := client.endpoints.add(serviceUpdate.Value); err != nil {
glog.Error(err)
}
case watch.REMOVE:
if err := client.endpoints.del(serviceUpdate.Value); err != nil {
glog.Error(err)
}
default:
glog.Warning("zrpc: unknown service update op")
}
}, time.Second)
// Register as a listener for passed service name
watcher.Watch(serviceName, serviceChannel)
return client
}