// writeKeyEvent trims the prefix of key path in a single Event under
// StoreKeysPrefix, serializes it and writes the resulting JSON to the given
// ResponseWriter, along with the appropriate headers.
func writeKeyEvent(w http.ResponseWriter, ev *store.Event, rt etcdserver.RaftTimer) error {
if ev == nil {
return errors.New("cannot write empty Event!")
}
w.Header().Set("Content-Type", "application/json")
w.Header().Set("X-Etcd-Index", fmt.Sprint(ev.EtcdIndex))
w.Header().Set("X-Raft-Index", fmt.Sprint(rt.Index()))
w.Header().Set("X-Raft-Term", fmt.Sprint(rt.Term()))
if ev.IsCreated() {
w.WriteHeader(http.StatusCreated)
}
ev = trimEventPrefix(ev, etcdserver.StoreKeysPrefix)
return json.NewEncoder(w).Encode(ev)
}
func handleKeyWatch(ctx context.Context, w http.ResponseWriter, wa store.Watcher, stream bool, rt etcdserver.RaftTimer) {
defer wa.Remove()
ech := wa.EventChan()
var nch <-chan bool
if x, ok := w.(http.CloseNotifier); ok {
nch = x.CloseNotify()
}
w.Header().Set("Content-Type", "application/json")
w.Header().Set("X-Etcd-Index", fmt.Sprint(wa.StartIndex()))
w.Header().Set("X-Raft-Index", fmt.Sprint(rt.Index()))
w.Header().Set("X-Raft-Term", fmt.Sprint(rt.Term()))
w.WriteHeader(http.StatusOK)
// Ensure headers are flushed early, in case of long polling
w.(http.Flusher).Flush()
for {
select {
case <-nch:
// Client closed connection. Nothing to do.
return
case <-ctx.Done():
// Timed out. net/http will close the connection for us, so nothing to do.
return
case ev, ok := <-ech:
if !ok {
// If the channel is closed this may be an indication of
// that notifications are much more than we are able to
// send to the client in time. Then we simply end streaming.
return
}
ev = trimEventPrefix(ev, etcdserver.StoreKeysPrefix)
if err := json.NewEncoder(w).Encode(ev); err != nil {
// Should never be reached
log.Printf("error writing event: %v\n", err)
return
}
if !stream {
return
}
w.(http.Flusher).Flush()
}
}
}