// Step advances the state machine using msgs. The ctx.Err() will be returned,
// if any.
func (n *Node) Step(ctx context.Context, m pb.Message) error {
ch := n.recvc
if m.Type == msgProp {
ch = n.propc
}
select {
case ch <- m:
return nil
case <-ctx.Done():
return ctx.Err()
case <-n.done:
return ErrStopped
}
}
// waitForEvent waits for a given Watcher to return its associated
// event. It returns a non-nil error if the given Context times out
// or the given ResponseWriter triggers a CloseNotify.
func waitForEvent(ctx context.Context, w http.ResponseWriter, wa store.Watcher) (*store.Event, error) {
// TODO(bmizerany): support streaming?
defer wa.Remove()
var nch <-chan bool
if x, ok := w.(http.CloseNotifier); ok {
nch = x.CloseNotify()
}
select {
case ev := <-wa.EventChan():
return ev, nil
case <-nch:
elog.TODO()
return nil, errClosed
case <-ctx.Done():
return nil, ctx.Err()
}
}
// configure sends configuration change through consensus then performs it.
// It will block until the change is performed or there is an error.
func (s *EtcdServer) configure(ctx context.Context, cc raftpb.ConfChange) error {
ch := s.w.Register(cc.ID)
if err := s.node.ProposeConfChange(ctx, cc); err != nil {
log.Printf("configure error: %v", err)
s.w.Trigger(cc.ID, nil)
return err
}
select {
case <-ch:
return nil
case <-ctx.Done():
s.w.Trigger(cc.ID, nil) // GC wait
return ctx.Err()
case <-s.done:
return ErrStopped
}
}
func handleWatch(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
}
if err := json.NewEncoder(w).Encode(ev); err != nil {
// Should never be reached
log.Println("error writing event: %v", err)
return
}
if !stream {
return
}
w.(http.Flusher).Flush()
}
}
}
// Do interprets r and performs an operation on s.Store according to r.Method
// and other fields. If r.Method is "POST", "PUT", "DELETE", or a "GET with
// Quorum == true, r will be sent through consensus before performing its
// respective operation. Do will block until an action is performed or there is
// an error.
func (s *Server) Do(ctx context.Context, r pb.Request) (Response, error) {
if r.Id == 0 {
panic("r.Id cannot be 0")
}
if r.Method == "GET" && r.Quorum {
r.Method = "QGET"
}
switch r.Method {
case "POST", "PUT", "DELETE", "QGET":
data, err := r.Marshal()
if err != nil {
return Response{}, err
}
ch := s.w.Register(r.Id)
s.Node.Propose(ctx, data)
select {
case x := <-ch:
resp := x.(Response)
return resp, resp.err
case <-ctx.Done():
s.w.Trigger(r.Id, nil) // GC wait
return Response{}, ctx.Err()
case <-s.done:
return Response{}, ErrStopped
}
case "GET":
switch {
case r.Wait:
wc, err := s.Store.Watch(r.Path, r.Recursive, false, r.Since)
if err != nil {
return Response{}, err
}
return Response{Watcher: wc}, nil
default:
ev, err := s.Store.Get(r.Path, r.Recursive, r.Sorted)
if err != nil {
return Response{}, err
}
return Response{Event: ev}, nil
}
default:
return Response{}, ErrUnknownMethod
}
}
func (c *httpClient) do(ctx context.Context, act httpAction) (*http.Response, []byte, error) {
req := act.httpRequest(c.endpoint)
rtchan := make(chan roundTripResponse, 1)
go func() {
resp, err := c.transport.RoundTrip(req)
rtchan <- roundTripResponse{resp: resp, err: err}
close(rtchan)
}()
var resp *http.Response
var err error
select {
case rtresp := <-rtchan:
resp, err = rtresp.resp, rtresp.err
case <-ctx.Done():
c.transport.CancelRequest(req)
// wait for request to actually exit before continuing
<-rtchan
err = ctx.Err()
}
// always check for resp nil-ness to deal with possible
// race conditions between channels above
defer func() {
if resp != nil {
resp.Body.Close()
}
}()
if err != nil {
return nil, nil, err
}
body, err := ioutil.ReadAll(resp.Body)
return resp, body, err
}