Moved to google.golang.org/genproto/googleapis/api/annotations

Fixes #52

vendor/github.com/go-kit/kit/sd/etcd/subscriber.go

@@ -0,0 +1,72 @@
+package etcd
+
+import (
+	"github.com/go-kit/kit/endpoint"
+	"github.com/go-kit/kit/log"
+	"github.com/go-kit/kit/sd"
+	"github.com/go-kit/kit/sd/cache"
+)
+
+// Subscriber yield endpoints stored in a certain etcd keyspace. Any kind of
+// change in that keyspace is watched and will update the Subscriber endpoints.
+type Subscriber struct {
+	client Client
+	prefix string
+	cache  *cache.Cache
+	logger log.Logger
+	quitc  chan struct{}
+}
+
+var _ sd.Subscriber = &Subscriber{}
+
+// NewSubscriber returns an etcd subscriber. It will start watching the given
+// prefix for changes, and update the endpoints.
+func NewSubscriber(c Client, prefix string, factory sd.Factory, logger log.Logger) (*Subscriber, error) {
+	s := &Subscriber{
+		client: c,
+		prefix: prefix,
+		cache:  cache.New(factory, logger),
+		logger: logger,
+		quitc:  make(chan struct{}),
+	}
+
+	instances, err := s.client.GetEntries(s.prefix)
+	if err == nil {
+		logger.Log("prefix", s.prefix, "instances", len(instances))
+	} else {
+		logger.Log("prefix", s.prefix, "err", err)
+	}
+	s.cache.Update(instances)
+
+	go s.loop()
+	return s, nil
+}
+
+func (s *Subscriber) loop() {
+	ch := make(chan struct{})
+	go s.client.WatchPrefix(s.prefix, ch)
+	for {
+		select {
+		case <-ch:
+			instances, err := s.client.GetEntries(s.prefix)
+			if err != nil {
+				s.logger.Log("msg", "failed to retrieve entries", "err", err)
+				continue
+			}
+			s.cache.Update(instances)
+
+		case <-s.quitc:
+			return
+		}
+	}
+}
+
+// Endpoints implements the Subscriber interface.
+func (s *Subscriber) Endpoints() ([]endpoint.Endpoint, error) {
+	return s.cache.Endpoints(), nil
+}
+
+// Stop terminates the Subscriber.
+func (s *Subscriber) Stop() {
+	close(s.quitc)
+}