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Merge pull request #2988 from nspcc-dev/client/close-blockers

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rpcclient: close WSClient subscriber on overflow
This commit is contained in:
Roman Khimov 2023-04-26 22:23:49 +03:00 committed by GitHub
commit dcea3f6107
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GPG key ID: 4AEE18F83AFDEB23
4 changed files with 238 additions and 57 deletions
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2
pkg/rpcclient/rpc_test.go
View file

@ -1803,7 +1803,7 @@ func TestRPCClients(t *testing.T) {
})
t.Run("WSClient", func(t *testing.T) {
testRPCClient(t, func(ctx context.Context, endpoint string, opts Options) (*Client, error) {
wsc, err := NewWS(ctx, httpURLtoWS(endpoint), opts)
wsc, err := NewWS(ctx, httpURLtoWS(endpoint), WSOptions{Options: opts})
require.NoError(t, err)
wsc.getNextRequestID = getTestRequestID
require.NoError(t, wsc.Init())

179
pkg/rpcclient/wsclient.go
View file

@ -38,7 +38,11 @@ import (
// will make WSClient wait for the channel reader to get the event and while
// it waits every other messages (subscription-related or request replies)
// will be blocked. This also means that subscription channel must be properly
// drained after unsubscription.
// drained after unsubscription. If CloseNotificationChannelIfFull option is on
// then the receiver channel will be closed immediately in case if a subsequent
// notification can't be sent to it, which means WSClient's operations are
// unblocking in this mode. No unsubscription is performed in this case, so it's
// still the user responsibility to unsubscribe.
//
// Any received subscription items (blocks/transactions/nofitications) are passed
// via pointers for efficiency, but the actual structures MUST NOT be changed, as
@ -47,7 +51,9 @@ import (
// only sent once per channel. The receiver channel will be closed by the WSClient
// immediately after MissedEvent is received from the server; no unsubscription
// is performed in this case, so it's the user responsibility to unsubscribe. It
// will also be closed on disconnection from server.
// will also be closed on disconnection from server or on situation when it's
// impossible to send a subsequent notification to the subscriber's channel and
// CloseNotificationChannelIfFull option is on.
type WSClient struct {
Client
// Notifications is a channel that is used to send events received from
@ -66,6 +72,7 @@ type WSClient struct {
Notifications chan Notification
ws *websocket.Conn
wsOpts WSOptions
done chan struct{}
requests chan *neorpc.Request
shutdown chan struct{}
@ -86,6 +93,21 @@ type WSClient struct {
respChannels map[uint64]chan *neorpc.Response
}
// WSOptions defines options for the web-socket RPC client. It contains a
// set of options for the underlying standard RPC client as far as
// WSClient-specific options. See Options documentation for more details.
type WSOptions struct {
Options
// CloseNotificationChannelIfFull allows WSClient to close a subscriber's
// receive channel in case if the channel isn't read properly and no more
// events can be pushed to it. This option, if set, allows to avoid WSClient
// blocking on a subsequent notification dispatch. However, if enabled, the
// corresponding subscription is kept even after receiver's channel closing,
// thus it's still the caller's duty to call Unsubscribe() for this
// subscription.
CloseNotificationChannelIfFull bool
}
// notificationReceiver is an interface aimed to provide WS subscriber functionality
// for different types of subscriptions.
type notificationReceiver interface {
@ -94,8 +116,11 @@ type notificationReceiver interface {
// Receiver returns notification receiver channel.
Receiver() any
// TrySend checks whether notification passes receiver filter and sends it
// to the underlying channel if so.
TrySend(ntf Notification) bool
// to the underlying channel if so. It is performed under subscriptions lock
// taken. nonBlocking denotes whether the receiving operation shouldn't block
// the client's operation. It returns whether notification matches the filter
// and whether the receiver channel is overflown.
TrySend(ntf Notification, nonBlocking bool) (bool, bool)
// Close closes underlying receiver channel.
Close()
}
@ -125,12 +150,21 @@ func (r *blockReceiver) Receiver() any {
}
// TrySend implements notificationReceiver interface.
func (r *blockReceiver) TrySend(ntf Notification) bool {
func (r *blockReceiver) TrySend(ntf Notification, nonBlocking bool) (bool, bool) {
if rpcevent.Matches(r, ntf) {
r.ch <- ntf.Value.(*block.Block)
return true
if nonBlocking {
select {
case r.ch <- ntf.Value.(*block.Block):
default:
return true, true
}
return false
} else {
r.ch <- ntf.Value.(*block.Block)
}
return true, false
}
return false, false
}
// Close implements notificationReceiver interface.
@ -163,12 +197,21 @@ func (r *txReceiver) Receiver() any {
}
// TrySend implements notificationReceiver interface.
func (r *txReceiver) TrySend(ntf Notification) bool {
func (r *txReceiver) TrySend(ntf Notification, nonBlocking bool) (bool, bool) {
if rpcevent.Matches(r, ntf) {
r.ch <- ntf.Value.(*transaction.Transaction)
return true
if nonBlocking {
select {
case r.ch <- ntf.Value.(*transaction.Transaction):
default:
return true, true
}
return false
} else {
r.ch <- ntf.Value.(*transaction.Transaction)
}
return true, false
}
return false, false
}
// Close implements notificationReceiver interface.
@ -201,12 +244,21 @@ func (r *executionNotificationReceiver) Receiver() any {
}
// TrySend implements notificationReceiver interface.
func (r *executionNotificationReceiver) TrySend(ntf Notification) bool {
func (r *executionNotificationReceiver) TrySend(ntf Notification, nonBlocking bool) (bool, bool) {
if rpcevent.Matches(r, ntf) {
r.ch <- ntf.Value.(*state.ContainedNotificationEvent)
return true
if nonBlocking {
select {
case r.ch <- ntf.Value.(*state.ContainedNotificationEvent):
default:
return true, true
}
return false
} else {
r.ch <- ntf.Value.(*state.ContainedNotificationEvent)
}
return true, false
}
return false, false
}
// Close implements notificationReceiver interface.
@ -239,12 +291,21 @@ func (r *executionReceiver) Receiver() any {
}
// TrySend implements notificationReceiver interface.
func (r *executionReceiver) TrySend(ntf Notification) bool {
func (r *executionReceiver) TrySend(ntf Notification, nonBlocking bool) (bool, bool) {
if rpcevent.Matches(r, ntf) {
r.ch <- ntf.Value.(*state.AppExecResult)
return true
if nonBlocking {
select {
case r.ch <- ntf.Value.(*state.AppExecResult):
default:
return true, true
}
return false
} else {
r.ch <- ntf.Value.(*state.AppExecResult)
}
return true, false
}
return false, false
}
// Close implements notificationReceiver interface.
@ -277,12 +338,21 @@ func (r *notaryRequestReceiver) Receiver() any {
}
// TrySend implements notificationReceiver interface.
func (r *notaryRequestReceiver) TrySend(ntf Notification) bool {
func (r *notaryRequestReceiver) TrySend(ntf Notification, nonBlocking bool) (bool, bool) {
if rpcevent.Matches(r, ntf) {
r.ch <- ntf.Value.(*result.NotaryRequestEvent)
return true
if nonBlocking {
select {
case r.ch <- ntf.Value.(*result.NotaryRequestEvent):
default:
return true, true
}
return false
} else {
r.ch <- ntf.Value.(*result.NotaryRequestEvent)
}
return true, false
}
return false, false
}
// Close implements notificationReceiver interface.
@ -316,12 +386,21 @@ func (r *naiveReceiver) Receiver() any {
}
// TrySend implements notificationReceiver interface.
func (r *naiveReceiver) TrySend(ntf Notification) bool {
func (r *naiveReceiver) TrySend(ntf Notification, nonBlocking bool) (bool, bool) {
if rpcevent.Matches(r, ntf) {
r.ch <- ntf
return true
if nonBlocking {
select {
case r.ch <- ntf:
default:
return true, true
}
return false
} else {
r.ch <- ntf
}
return true, false
}
return false, false
}
// Close implements notificationReceiver interface.
@ -382,7 +461,7 @@ var errConnClosedByUser = errors.New("connection closed by user")
// connection). You need to use websocket URL for it like `ws://1.2.3.4/ws`.
// You should call Init method to initialize the network magic the client is
// operating on.
func NewWS(ctx context.Context, endpoint string, opts Options) (*WSClient, error) {
func NewWS(ctx context.Context, endpoint string, opts WSOptions) (*WSClient, error) {
dialer := websocket.Dialer{HandshakeTimeout: opts.DialTimeout}
ws, resp, err := dialer.DialContext(ctx, endpoint, nil)
if resp != nil && resp.Body != nil { // Can be non-nil even with error returned.
@ -405,6 +484,7 @@ func NewWS(ctx context.Context, endpoint string, opts Options) (*WSClient, error
Notifications: make(chan Notification),
ws: ws,
wsOpts: opts,
shutdown: make(chan struct{}),
done: make(chan struct{}),
closeCalled: *atomic.NewBool(false),
@ -414,7 +494,7 @@ func NewWS(ctx context.Context, endpoint string, opts Options) (*WSClient, error
receivers: make(map[any][]string),
}
err = initClient(ctx, &wsc.Client, endpoint, opts)
err = initClient(ctx, &wsc.Client, endpoint, opts.Options)
if err != nil {
return nil, err
}
@ -542,16 +622,30 @@ readloop:
c.respLock.Unlock()
c.subscriptionsLock.Lock()
for rcvrCh, ids := range c.receivers {
rcvr := c.subscriptions[ids[0]]
c.dropSubCh(rcvrCh, ids[0], true)
}
c.subscriptionsLock.Unlock()
c.Client.ctxCancel()
}
// dropSubCh closes corresponding subscriber's channel and removes it from the
// receivers map. If the channel belongs to a naive subscriber then it will be
// closed manually without call to Close(). The channel is still being kept in
// the subscribers map as technically the server-side subscription still exists
// and the user is responsible for unsubscription. This method must be called
// under subscriptionsLock taken. It's the caller's duty to ensure dropSubCh
// will be called once per channel, otherwise panic will occur.
func (c *WSClient) dropSubCh(rcvrCh any, id string, ignoreCloseNotificationChannelIfFull bool) {
if ignoreCloseNotificationChannelIfFull || c.wsOpts.CloseNotificationChannelIfFull {
rcvr := c.subscriptions[id]
_, ok := rcvr.(*naiveReceiver)
if !ok { // naiveReceiver uses c.Notifications that is about to be closed below.
c.subscriptions[ids[0]].Close()
if ok { // naiveReceiver uses c.Notifications that should be handled separately.
close(c.Notifications)
} else {
c.subscriptions[id].Close()
}
delete(c.receivers, rcvrCh)
}
c.subscriptionsLock.Unlock()
close(c.Notifications)
c.Client.ctxCancel()
}
func (c *WSClient) wsWriter() {
@ -604,15 +698,20 @@ func (c *WSClient) notifySubscribers(ntf Notification) {
c.subscriptionsLock.Unlock()
return
}
c.subscriptionsLock.RLock()
for _, ids := range c.receivers {
c.subscriptionsLock.Lock()
for rcvrCh, ids := range c.receivers {
for _, id := range ids {
if c.subscriptions[id].TrySend(ntf) {
ok, dropCh := c.subscriptions[id].TrySend(ntf, c.wsOpts.CloseNotificationChannelIfFull)
if dropCh {
c.dropSubCh(rcvrCh, id, false)
break // strictly single drop per channel
}
if ok {
break // strictly one notification per channel
}
}
}
c.subscriptionsLock.RUnlock()
c.subscriptionsLock.Unlock()
}
func (c *WSClient) unregisterRespChannel(id uint64) {

110
pkg/rpcclient/wsclient_test.go
View file

@ -31,7 +31,7 @@ import (
func TestWSClientClose(t *testing.T) {
srv := initTestServer(t, `{"jsonrpc": "2.0", "id": 1, "result": "55aaff00"}`)
wsc, err := NewWS(context.TODO(), httpURLtoWS(srv.URL), Options{})
wsc, err := NewWS(context.TODO(), httpURLtoWS(srv.URL), WSOptions{})
require.NoError(t, err)
wsc.getNextRequestID = getTestRequestID
bCh := make(chan *block.Block)
@ -70,7 +70,7 @@ func TestWSClientSubscription(t *testing.T) {
for name, f := range cases {
t.Run(name, func(t *testing.T) {
srv := initTestServer(t, `{"jsonrpc": "2.0", "id": 1, "result": "55aaff00"}`)
wsc, err := NewWS(context.TODO(), httpURLtoWS(srv.URL), Options{})
wsc, err := NewWS(context.TODO(), httpURLtoWS(srv.URL), WSOptions{})
require.NoError(t, err)
wsc.getNextRequestID = getTestRequestID
require.NoError(t, wsc.Init())
@ -84,7 +84,7 @@ func TestWSClientSubscription(t *testing.T) {
for name, f := range cases {
t.Run(name, func(t *testing.T) {
srv := initTestServer(t, `{"jsonrpc": "2.0", "id": 1, "error":{"code":-32602,"message":"Invalid Params"}}`)
wsc, err := NewWS(context.TODO(), httpURLtoWS(srv.URL), Options{})
wsc, err := NewWS(context.TODO(), httpURLtoWS(srv.URL), WSOptions{})
require.NoError(t, err)
wsc.getNextRequestID = getTestRequestID
require.NoError(t, wsc.Init())
@ -134,7 +134,7 @@ func TestWSClientUnsubscription(t *testing.T) {
for name, rc := range cases {
t.Run(name, func(t *testing.T) {
srv := initTestServer(t, rc.response)
wsc, err := NewWS(context.TODO(), httpURLtoWS(srv.URL), Options{})
wsc, err := NewWS(context.TODO(), httpURLtoWS(srv.URL), WSOptions{})
require.NoError(t, err)
wsc.getNextRequestID = getTestRequestID
require.NoError(t, wsc.Init())
@ -170,7 +170,7 @@ func TestWSClientEvents(t *testing.T) {
return
}
}))
wsc, err := NewWS(context.TODO(), httpURLtoWS(srv.URL), Options{})
wsc, err := NewWS(context.TODO(), httpURLtoWS(srv.URL), WSOptions{})
require.NoError(t, err)
wsc.getNextRequestID = getTestRequestID
wsc.cacheLock.Lock()
@ -289,10 +289,92 @@ func TestWSClientEvents(t *testing.T) {
require.False(t, ok)
}
func TestWSClientNonBlockingEvents(t *testing.T) {
// Use buffered channel as a receiver to check it will be closed by WSClient
// after overflow if CloseNotificationChannelIfFull option is enabled.
const chCap = 3
bCh := make(chan *block.Block, chCap)
// Events from RPC server testchain. Require events len to be larger than chCap to reach
// subscriber's chanel overflow.
var events = []string{
fmt.Sprintf(`{"jsonrpc":"2.0","method":"block_added","params":[%s]}`, b1Verbose),
fmt.Sprintf(`{"jsonrpc":"2.0","method":"block_added","params":[%s]}`, b1Verbose),
fmt.Sprintf(`{"jsonrpc":"2.0","method":"block_added","params":[%s]}`, b1Verbose),
fmt.Sprintf(`{"jsonrpc":"2.0","method":"block_added","params":[%s]}`, b1Verbose),
fmt.Sprintf(`{"jsonrpc":"2.0","method":"block_added","params":[%s]}`, b1Verbose),
}
require.True(t, chCap < len(events))
var blocksSent atomic.Bool
srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
if req.URL.Path == "/ws" && req.Method == "GET" {
var upgrader = websocket.Upgrader{}
ws, err := upgrader.Upgrade(w, req, nil)
require.NoError(t, err)
for _, event := range events {
err = ws.SetWriteDeadline(time.Now().Add(2 * time.Second))
require.NoError(t, err)
err = ws.WriteMessage(1, []byte(event))
if err != nil {
break
}
}
blocksSent.Store(true)
ws.Close()
return
}
}))
wsc, err := NewWS(context.TODO(), httpURLtoWS(srv.URL), WSOptions{CloseNotificationChannelIfFull: true})
require.NoError(t, err)
wsc.getNextRequestID = getTestRequestID
wsc.cacheLock.Lock()
wsc.cache.initDone = true // Our server mock is restricted, so perform initialisation manually.
wsc.cache.network = netmode.UnitTestNet
wsc.cacheLock.Unlock()
// Our server mock is restricted, so perform subscriptions manually.
wsc.subscriptionsLock.Lock()
wsc.subscriptions["0"] = &blockReceiver{ch: bCh}
wsc.subscriptions["1"] = &blockReceiver{ch: bCh}
wsc.receivers[chan<- *block.Block(bCh)] = []string{"0", "1"}
wsc.subscriptionsLock.Unlock()
// Check that events are sent to WSClient.
require.Eventually(t, func() bool {
return blocksSent.Load()
}, time.Second, 100*time.Millisecond)
// Check that block receiver channel was removed from the receivers list due to overflow.
require.Eventually(t, func() bool {
wsc.subscriptionsLock.RLock()
defer wsc.subscriptionsLock.RUnlock()
return len(wsc.receivers) == 0
}, 2*time.Second, 200*time.Millisecond)
// Check that subscriptions are still there and waiting for the call to Unsubscribe()
// to be excluded from the subscriptions map.
wsc.subscriptionsLock.RLock()
require.True(t, len(wsc.subscriptions) == 2)
wsc.subscriptionsLock.RUnlock()
// Check that receiver was closed after overflow.
for i := 0; i < chCap; i++ {
_, ok := <-bCh
require.True(t, ok)
}
select {
case _, ok := <-bCh:
require.False(t, ok)
default:
t.Fatal("channel wasn't closed by WSClient")
}
}
func TestWSExecutionVMStateCheck(t *testing.T) {
// Will answer successfully if request slips through.
srv := initTestServer(t, `{"jsonrpc": "2.0", "id": 1, "result": "55aaff00"}`)
wsc, err := NewWS(context.TODO(), httpURLtoWS(srv.URL), Options{})
wsc, err := NewWS(context.TODO(), httpURLtoWS(srv.URL), WSOptions{})
require.NoError(t, err)
wsc.getNextRequestID = getTestRequestID
require.NoError(t, wsc.Init())
@ -527,7 +609,7 @@ func TestWSFilteredSubscriptions(t *testing.T) {
ws.Close()
}
}))
wsc, err := NewWS(context.TODO(), httpURLtoWS(srv.URL), Options{})
wsc, err := NewWS(context.TODO(), httpURLtoWS(srv.URL), WSOptions{})
require.NoError(t, err)
wsc.getNextRequestID = getTestRequestID
wsc.cache.network = netmode.UnitTestNet
@ -541,14 +623,14 @@ func TestNewWS(t *testing.T) {
srv := initTestServer(t, "")
t.Run("good", func(t *testing.T) {
c, err := NewWS(context.TODO(), httpURLtoWS(srv.URL), Options{})
c, err := NewWS(context.TODO(), httpURLtoWS(srv.URL), WSOptions{})
require.NoError(t, err)
c.getNextRequestID = getTestRequestID
c.cache.network = netmode.UnitTestNet
require.NoError(t, c.Init())
})
t.Run("bad URL", func(t *testing.T) {
_, err := NewWS(context.TODO(), strings.TrimPrefix(srv.URL, "http://"), Options{})
_, err := NewWS(context.TODO(), strings.TrimPrefix(srv.URL, "http://"), WSOptions{})
require.Error(t, err)
})
}
@ -605,7 +687,7 @@ func TestWSConcurrentAccess(t *testing.T) {
}))
t.Cleanup(srv.Close)
wsc, err := NewWS(context.TODO(), httpURLtoWS(srv.URL), Options{})
wsc, err := NewWS(context.TODO(), httpURLtoWS(srv.URL), WSOptions{})
require.NoError(t, err)
batchCount := 100
completed := atomic.NewInt32(0)
@ -649,7 +731,7 @@ func TestWSConcurrentAccess(t *testing.T) {
func TestWSDoubleClose(t *testing.T) {
srv := initTestServer(t, "")
c, err := NewWS(context.TODO(), httpURLtoWS(srv.URL), Options{})
c, err := NewWS(context.TODO(), httpURLtoWS(srv.URL), WSOptions{})
require.NoError(t, err)
require.NotPanics(t, func() {
@ -661,7 +743,7 @@ func TestWSDoubleClose(t *testing.T) {
func TestWS_RequestAfterClose(t *testing.T) {
srv := initTestServer(t, "")
c, err := NewWS(context.TODO(), httpURLtoWS(srv.URL), Options{})
c, err := NewWS(context.TODO(), httpURLtoWS(srv.URL), WSOptions{})
require.NoError(t, err)
c.Close()
@ -676,7 +758,7 @@ func TestWS_RequestAfterClose(t *testing.T) {
func TestWSClient_ConnClosedError(t *testing.T) {
t.Run("standard closing", func(t *testing.T) {
srv := initTestServer(t, `{"jsonrpc": "2.0", "id": 1, "result": 123}`)
c, err := NewWS(context.TODO(), httpURLtoWS(srv.URL), Options{})
c, err := NewWS(context.TODO(), httpURLtoWS(srv.URL), WSOptions{})
require.NoError(t, err)
// Check client is working.
@ -692,7 +774,7 @@ func TestWSClient_ConnClosedError(t *testing.T) {
t.Run("malformed request", func(t *testing.T) {
srv := initTestServer(t, "")
c, err := NewWS(context.TODO(), httpURLtoWS(srv.URL), Options{})
c, err := NewWS(context.TODO(), httpURLtoWS(srv.URL), WSOptions{})
require.NoError(t, err)
defaultMaxBlockSize := 262144

4
pkg/services/rpcsrv/client_test.go
View file

@ -2073,7 +2073,7 @@ func mkSubsClient(t *testing.T, rpcSrv *Server, httpSrv *httptest.Server, local
icl, err = rpcclient.NewInternal(context.Background(), rpcSrv.RegisterLocal)
} else {
url := "ws" + strings.TrimPrefix(httpSrv.URL, "http") + "/ws"
c, err = rpcclient.NewWS(context.Background(), url, rpcclient.Options{})
c, err = rpcclient.NewWS(context.Background(), url, rpcclient.WSOptions{})
}
require.NoError(t, err)
if local {
@ -2239,7 +2239,7 @@ func TestWSClientHandshakeError(t *testing.T) {
defer rpcSrv.Shutdown()
url := "ws" + strings.TrimPrefix(httpSrv.URL, "http") + "/ws"
_, err := rpcclient.NewWS(context.Background(), url, rpcclient.Options{})
_, err := rpcclient.NewWS(context.Background(), url, rpcclient.WSOptions{})
require.ErrorContains(t, err, "websocket users limit reached")
}