Merge pull request #3828 from fyfyrchik/update-feeds

rpcsrv: allow to configure subscription limit

docs/node-configuration.md

@@ -251,6 +251,7 @@ RPC:
   MaxRequestBodyBytes: 5242880
   MaxRequestHeaderBytes: 1048576
   MaxWebSocketClients: 64
+  MaxWebSocketFeeds: 16
   SessionEnabled: false
   SessionExpirationTime: 15
   SessionBackedByMPT: false
@@ -296,6 +297,9 @@ where:
   number (64 by default). Attempts to establish additional connections will
   lead to websocket handshake failures. Use "-1" to disable websocket
   connections (0 will lead to using the default value).
+- `MaxWebSocketFeeds` -- the maximum simultaneous event subscriptions number
+  for a single client (16 by default). Attemps to create additional subscriptions
+  will lead to error.
 - `SessionEnabled` denotes whether session-based iterator JSON-RPC API is enabled.
   If true, then all iterators got from `invoke*` calls will be stored as sessions
   on the server side available for further traverse. `traverseiterator` and

docs/notifications.md

@@ -58,6 +58,9 @@ method. Upon successful subscription, clients receive subscription ID for
 subsequent management of this subscription. Subscription is only valid for
 connection lifetime, no long-term client identification is being made.
 
+The maximum number of simultaneous subscriptions can be set server-side
+via `MaxWebSocketFeeds` setting.
+
 Errors are not described down below, but they can be returned as standard
 JSON-RPC errors (most often caused by invalid parameters).
 

pkg/config/rpc_config.go

@@ -19,6 +19,7 @@ type (
 		MaxRequestBodyBytes       int           `yaml:"MaxRequestBodyBytes"`
 		MaxRequestHeaderBytes     int           `yaml:"MaxRequestHeaderBytes"`
 		MaxWebSocketClients       int           `yaml:"MaxWebSocketClients"`
+		MaxWebSocketFeeds         int           `yaml:"MaxWebSocketFeeds"`
 		SessionEnabled            bool          `yaml:"SessionEnabled"`
 		SessionExpirationTime     int           `yaml:"SessionExpirationTime"`
 		SessionBackedByMPT        bool          `yaml:"SessionBackedByMPT"`

pkg/services/rpcsrv/server.go

@@ -311,6 +311,10 @@ func New(chain Ledger, conf config.RPC, coreServer *network.Server,
 		conf.MaxWebSocketClients = defaultMaxWebSocketClients
 		log.Info("MaxWebSocketClients is not set or wrong, setting default value", zap.Int("MaxWebSocketClients", defaultMaxWebSocketClients))
 	}
+	if conf.MaxWebSocketFeeds == 0 {
+		conf.MaxWebSocketFeeds = defaultMaxFeeds
+		log.Info("MaxWebSocketFeeds is not set or wrong, setting default value", zap.Int("MaxWebSocketFeeds", defaultMaxFeeds))
+	}
 	var oracleWrapped = new(atomic.Value)
 	if orc != nil {
 		oracleWrapped.Store(orc)
@@ -522,7 +526,7 @@ func (s *Server) handleHTTPRequest(w http.ResponseWriter, httpRequest *http.Requ
 		}
 		resChan := make(chan abstractResult) // response.abstract or response.abstractBatch
 		subChan := make(chan intEvent, notificationBufSize)
-		subscr := &subscriber{writer: subChan}
+		subscr := &subscriber{writer: subChan, feeds: make([]feed, s.config.MaxWebSocketFeeds)}
 		s.subsLock.Lock()
 		s.subscribers[subscr] = true
 		s.subsLock.Unlock()
@@ -560,7 +564,7 @@ func (s *Server) handleHTTPRequest(w http.ResponseWriter, httpRequest *http.Requ
 // RegisterLocal performs local client registration.
 func (s *Server) RegisterLocal(ctx context.Context, events chan<- neorpc.Notification) func(*neorpc.Request) (*neorpc.Response, error) {
 	subChan := make(chan intEvent, notificationBufSize)
-	subscr := &subscriber{writer: subChan}
+	subscr := &subscriber{writer: subChan, feeds: make([]feed, s.config.MaxWebSocketFeeds)}
 	s.subsLock.Lock()
 	s.subscribers[subscr] = true
 	s.subsLock.Unlock()

pkg/services/rpcsrv/subscription.go

@@ -23,7 +23,7 @@ type (
 		// cheaper doing it this way rather than creating a map),
 		// pointing to an EventID is an obvious overkill at the moment, but
 		// that's not for long.
-		feeds [maxFeeds]feed
+		feeds []feed
 	}
 	// feed stores subscriber's desired event ID with filter.
 	feed struct {
@@ -43,8 +43,8 @@ func (f feed) Filter() neorpc.SubscriptionFilter {
 }
 
 const (
-	// Maximum number of subscriptions per one client.
-	maxFeeds = 16
+	// The default maximum number of subscriptions per one client.
+	defaultMaxFeeds = 16
 
 	// This sets notification messages buffer depth. It may seem to be quite
 	// big, but there is a big gap in speed between internal event processing

pkg/services/rpcsrv/subscription_test.go

@@ -4,6 +4,7 @@ import (
 	"encoding/base64"
 	"encoding/json"
 	"fmt"
+	"net/http/httptest"
 	"strings"
 	"sync"
 	"testing"
@@ -76,7 +77,11 @@ func getNotification(t *testing.T, respCh <-chan []byte) *neorpc.Notification {
 
 func initCleanServerAndWSClient(t *testing.T, startNetworkServer ...bool) (*core.Blockchain, *Server, *websocket.Conn, chan []byte) {
 	chain, rpcSrv, httpSrv := initClearServerWithInMemoryChain(t)
+	ws, respMsgs := initWSClient(t, httpSrv, rpcSrv, startNetworkServer...)
+	return chain, rpcSrv, ws, respMsgs
+}
 
+func initWSClient(t *testing.T, httpSrv *httptest.Server, rpcSrv *Server, startNetworkServer ...bool) (*websocket.Conn, chan []byte) {
 	dialer := websocket.Dialer{HandshakeTimeout: 5 * time.Second}
 	url := "ws" + strings.TrimPrefix(httpSrv.URL, "http") + "/ws"
 	ws, r, err := dialer.Dial(url, nil)
@@ -108,7 +113,7 @@ func initCleanServerAndWSClient(t *testing.T, startNetworkServer ...bool) (*core
 			rpcSrv.coreServer.Shutdown()
 		}
 	})
-	return chain, rpcSrv, ws, respMsgs
+	return ws, respMsgs
 }
 
 func callSubscribe(t *testing.T, ws *websocket.Conn, msgs <-chan []byte, params string) string {
@@ -577,9 +582,10 @@ func TestHeaderOfAddedBlockSubscriptions(t *testing.T) {
 	callUnsubscribe(t, c, respMsgs, headerSubID)
 }
 
-func TestMaxSubscriptions(t *testing.T) {
+func testMaxSubscriptions(t *testing.T, f func(*config.Config), maxFeeds int) {
 	var subIDs = make([]string, 0)
-	_, _, c, respMsgs := initCleanServerAndWSClient(t)
+	_, rpcSrv, httpSrv := initClearServerWithCustomConfig(t, f)
+	c, respMsgs := initWSClient(t, httpSrv, rpcSrv)
 
 	for i := range maxFeeds + 1 {
 		var s string
@@ -600,6 +606,17 @@ func TestMaxSubscriptions(t *testing.T) {
 	}
 }
 
+func TestMaxSubscriptions(t *testing.T) {
+	t.Run("default", func(t *testing.T) {
+		testMaxSubscriptions(t, nil, defaultMaxFeeds)
+	})
+	t.Run("maxfeeds=x2", func(t *testing.T) {
+		testMaxSubscriptions(t, func(c *config.Config) {
+			c.ApplicationConfiguration.RPC.MaxWebSocketFeeds = defaultMaxFeeds * 2
+		}, defaultMaxFeeds*2)
+	})
+}
+
 func TestBadSubUnsub(t *testing.T) {
 	var subCases = map[string]string{
 		"no params":              `{"jsonrpc": "2.0", "method": "subscribe", "params": [], "id": 1}`,