rpc: add subscriber queue overflow check

It's not practical adding server-side tests for 2.0 (as it requires generating
more blocks), so we'll leave it for 3.0.
This commit is contained in:
Roman Khimov 2020-05-12 22:38:29 +03:00
parent 1d5734c882
commit 966ff28091
6 changed files with 72 additions and 21 deletions

View file

@ -125,7 +125,7 @@ readloop:
}
var slice []json.RawMessage
err = json.Unmarshal(rr.RawParams, &slice)
if err != nil || len(slice) != 1 {
if err != nil || (event != response.MissedEventID && len(slice) != 1) {
// Bad event received.
break
}
@ -139,15 +139,19 @@ readloop:
val = new(result.NotificationEvent)
case response.ExecutionEventID:
val = new(result.ApplicationLog)
case response.MissedEventID:
// No value.
default:
// Bad event received.
break readloop
}
if event != response.MissedEventID {
err = json.Unmarshal(slice[0], val)
if err != nil || len(slice) != 1 {
// Bad event received.
break
}
}
c.Notifications <- Notification{event, val}
} else if rr.RawID != nil && (rr.Error != nil || rr.Result != nil) {
resp := new(response.Raw)

View file

@ -108,6 +108,7 @@ func TestWSClientEvents(t *testing.T) {
`{"jsonrpc":"2.0","method":"notification_from_execution","params":[{"contract":"0xc2789e5ab9bab828743833965b1df0d5fbcc206f","state":{"type":"Array","value":[{"type":"ByteArray","value":"636f6e74726163742063616c6c"},{"type":"ByteArray","value":"507574"},{"type":"Array","value":[{"type":"ByteArray","value":"746573746b6579"},{"type":"ByteArray","value":"7465737476616c7565"}]}]}}]}`,
`{"jsonrpc":"2.0","method":"transaction_added","params":[{"txid":"0x93670859cc8a42f6ea994869c944879678d33d7501d388f5a446a8c7de147df7","size":60,"type":"InvocationTransaction","version":1,"attributes":[],"vin":[],"vout":[],"scripts":[],"script":"097465737476616c756507746573746b657952c103507574676f20ccfbd5f01d5b9633387428b8bab95a9e78c2"}]}`,
`{"jsonrpc":"2.0","method":"block_added","params":[{"version":0,"previousblockhash":"0x33f3e0e24542b2ec3b6420e6881c31f6460a39a4e733d88f7557cbcc3b5ed560","merkleroot":"0x9d922c5cfd4c8cd1da7a6b2265061998dc438bd0dea7145192e2858155e6c57a","time":1586154525,"height":205,"nonce":1111,"next_consensus":"0xa21e4f7178607089e4fe9fab1300d1f5a3d348be","script":{"invocation":"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","verification":"532102103a7f7dd016558597f7960d27c516a4394fd968b9e65155eb4b013e4040406e2102a7bc55fe8684e0119768d104ba30795bdcc86619e864add26156723ed185cd622102b3622bf4017bdfe317c58aed5f4c753f206b7db896046fa7d774bbc4bf7f8dc22103d90c07df63e690ce77912e10ab51acc944b66860237b608c4f8f8309e71ee69954ae"},"tx":[{"txid":"0xf9adfde059810f37b3d0686d67f6b29034e0c669537df7e59b40c14a0508b9ed","size":10,"type":"MinerTransaction","version":0,"attributes":[],"vin":[],"vout":[],"scripts":[]},{"txid":"0x93670859cc8a42f6ea994869c944879678d33d7501d388f5a446a8c7de147df7","size":60,"type":"InvocationTransaction","version":1,"attributes":[],"vin":[],"vout":[],"scripts":[],"script":"097465737476616c756507746573746b657952c103507574676f20ccfbd5f01d5b9633387428b8bab95a9e78c2"}]}]}`,
`{"jsonrpc":"2.0","method":"event_missed","params":[]}`,
}
srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
if req.URL.Path == "/ws" && req.Method == "GET" {

View file

@ -23,6 +23,8 @@ const (
NotificationEventID
// ExecutionEventID is used for `transaction_executed` events.
ExecutionEventID
// MissedEventID notifies user of missed events.
MissedEventID EventID = 255
)
// String is a good old Stringer implementation.
@ -36,6 +38,8 @@ func (e EventID) String() string {
return "notification_from_execution"
case ExecutionEventID:
return "transaction_executed"
case MissedEventID:
return "event_missed"
default:
return "unknown"
}
@ -52,6 +56,8 @@ func GetEventIDFromString(s string) (EventID, error) {
return NotificationEventID, nil
case "transaction_executed":
return ExecutionEventID, nil
case "event_missed":
return MissedEventID, nil
default:
return 255, errors.New("invalid stream name")
}

View file

@ -295,37 +295,49 @@ func (s *Server) handleRequest(req *request.In, sub *subscriber) response.Raw {
func (s *Server) handleWsWrites(ws *websocket.Conn, resChan <-chan response.Raw, subChan <-chan *websocket.PreparedMessage) {
pingTicker := time.NewTicker(wsPingPeriod)
defer ws.Close()
defer pingTicker.Stop()
eventloop:
for {
select {
case <-s.shutdown:
// Signal to the reader routine.
ws.Close()
return
break eventloop
case event, ok := <-subChan:
if !ok {
return
break eventloop
}
ws.SetWriteDeadline(time.Now().Add(wsWriteLimit))
if err := ws.WritePreparedMessage(event); err != nil {
return
break eventloop
}
case res, ok := <-resChan:
if !ok {
return
break eventloop
}
ws.SetWriteDeadline(time.Now().Add(wsWriteLimit))
if err := ws.WriteJSON(res); err != nil {
return
break eventloop
}
case <-pingTicker.C:
ws.SetWriteDeadline(time.Now().Add(wsWriteLimit))
if err := ws.WriteMessage(websocket.PingMessage, []byte{}); err != nil {
return
break eventloop
}
}
}
ws.Close()
pingTicker.Stop()
// Drain notification channel as there might be some goroutines blocked
// on it.
drainloop:
for {
select {
case _, ok := <-subChan:
if !ok {
break drainloop
}
default:
break drainloop
}
}
}
func (s *Server) handleWsReads(ws *websocket.Conn, resChan chan<- response.Raw, subscr *subscriber) {
@ -1131,7 +1143,7 @@ func (s *Server) subscribe(reqParams request.Params, sub *subscriber) (interface
return nil, response.ErrInvalidParams
}
event, err := response.GetEventIDFromString(streamName)
if err != nil {
if err != nil || event == response.MissedEventID {
return nil, response.ErrInvalidParams
}
s.subsLock.Lock()
@ -1233,6 +1245,20 @@ func (s *Server) unsubscribeFromChannel(event response.EventID) {
}
func (s *Server) handleSubEvents() {
b, err := json.Marshal(response.Notification{
JSONRPC: request.JSONRPCVersion,
Event: response.MissedEventID,
Payload: make([]interface{}, 0),
})
if err != nil {
s.log.Error("fatal: failed to marshal overflow event", zap.Error(err))
return
}
overflowMsg, err := websocket.NewPreparedMessage(websocket.TextMessage, b)
if err != nil {
s.log.Error("fatal: failed to prepare overflow message", zap.Error(err))
return
}
chloop:
for {
var resp = response.Notification{
@ -1259,10 +1285,13 @@ chloop:
s.subsLock.RLock()
subloop:
for sub := range s.subscribers {
if sub.overflown.Load() {
continue
}
for _, subID := range sub.feeds {
if subID == resp.Event {
if msg == nil {
b, err := json.Marshal(resp)
b, err = json.Marshal(resp)
if err != nil {
s.log.Error("failed to marshal notification",
zap.Error(err),
@ -1277,7 +1306,16 @@ chloop:
break subloop
}
}
sub.writer <- msg
select {
case sub.writer <- msg:
default:
sub.overflown.Store(true)
// MissedEvent is to be delivered eventually.
go func(sub *subscriber) {
sub.writer <- overflowMsg
sub.overflown.Store(false)
}(sub)
}
// The message is sent only once per subscriber.
break
}

View file

@ -3,6 +3,7 @@ package server
import (
"github.com/gorilla/websocket"
"github.com/nspcc-dev/neo-go/pkg/rpc/response"
"go.uber.org/atomic"
)
type (
@ -10,7 +11,7 @@ type (
subscriber struct {
writer chan<- *websocket.PreparedMessage
ws *websocket.Conn
overflown atomic.Bool
// These work like slots as there is not a lot of them (it's
// cheaper doing it this way rather than creating a map),
// pointing to EventID is an obvious overkill at the moment, but

View file

@ -160,6 +160,7 @@ func TestBadSubUnsub(t *testing.T) {
"no params": `{"jsonrpc": "2.0", "method": "subscribe", "params": [], "id": 1}`,
"bad (non-string) event": `{"jsonrpc": "2.0", "method": "subscribe", "params": [1], "id": 1}`,
"bad (wrong) event": `{"jsonrpc": "2.0", "method": "subscribe", "params": ["block_removed"], "id": 1}`,
"missed event": `{"jsonrpc": "2.0", "method": "subscribe", "params": ["event_missed"], "id": 1}`,
}
var unsubCases = map[string]string{
"no params": `{"jsonrpc": "2.0", "method": "unsubscribe", "params": [], "id": 1}`,