Esempio n. 1
0
// Subscribe watches etcd changes and generates structured events telling vulcand to add or delete frontends, hosts etc.
// It is a blocking function.
func (n *ng) Subscribe(changes chan interface{}, cancelC chan bool) error {
	// This index helps us to get changes in sequence, as they were performed by clients.
	waitIndex := uint64(0)
	for {
		response, err := n.client.Watch(n.etcdKey, waitIndex, true, nil, cancelC)
		if err != nil {
			switch err {
			case etcd.ErrWatchStoppedByUser:
				log.Infof("Stop watching: graceful shutdown")
				return nil
			default:
				log.Errorf("unexpected error: %s, stop watching", err)
				return err
			}
		}
		waitIndex = response.EtcdIndex + 1
		log.Infof("%s", responseToString(response))
		change, err := n.parseChange(response)
		if err != nil {
			log.Warningf("Ignore '%s', error: %s", responseToString(response), err)
			continue
		}
		if change != nil {
			log.Infof("%v", change)
			select {
			case changes <- change:
			case <-cancelC:
				return nil
			}
		}
	}
}
Esempio n. 2
0
// Subscribe watches etcd changes and generates structured events telling vulcand to add or delete frontends, hosts etc.
// It is a blocking function.
func (n *ng) Subscribe(changes chan interface{}, cancelC chan bool) error {
	w := n.kapi.Watcher(n.etcdKey, &etcd.WatcherOptions{AfterIndex: 0, Recursive: true})
	for {
		response, err := w.Next(n.context)
		if err != nil {
			switch err {
			case context.Canceled:
				log.Infof("Stop watching: graceful shutdown")
				return nil
			default:
				log.Errorf("unexpected error: %s, stop watching", err)
				return err
			}
		}
		log.Infof("%s", responseToString(response))
		change, err := n.parseChange(response)
		if err != nil {
			log.Warningf("Ignore '%s', error: %s", responseToString(response), err)
			continue
		}
		if change != nil {
			log.Infof("%v", change)
			select {
			case changes <- change:
			case <-cancelC:
				return nil
			}
		}
	}
}