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Fix hang during shutdown when client is connected.

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Closes #108.
This commit is contained in:
Javed Khan 2014-07-04 11:24:45 +05:30 committed by Josh Rickmar
parent 061a220354
commit 9036d36e68
1 changed files with 62 additions and 33 deletions
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95
rpcserver.go
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@ -477,7 +477,6 @@ func (s *rpcServer) WebsocketClientRead(wsc *websocketClient) {
}
wsc.allRequests <- request
}
s.wg.Done()
}
type rawRequest struct {
@ -582,40 +581,57 @@ type unauthedRequest struct {
func (s *rpcServer) WebsocketClientGateway(wsc *websocketClient) {
out:
for request := range wsc.allRequests {
// Get the method of the request and check whether it should be
// handled by wallet or passed down to btcd. If the latter,
// handle in a new goroutine (to not block or be blocked by
// the handling of actual wallet requests).
//
// This is done by unmarshaling the JSON bytes into a rawRequest
// to avoid the mangling of unmarshaling and re-marshaling of
// large JSON numbers, as well as the overhead of unneeded
// unmarshals and marshals.
var raw rawRequest
if err := json.Unmarshal(request, &raw); err != nil {
if !wsc.authenticated {
// Disconnect immediately.
// A for-select with a read of the quit channel is used instead of a
// for-range to provide clean shutdown. This is necessary due to
// WebsocketClientRead (which sends to the allRequests chan) not closing
// allRequests during shutdown if the remote websocket client is still
// connected.
for {
select {
case request, ok := <-wsc.allRequests:
if !ok {
// client disconnected
break out
}
err = wsc.send(marshalError(idPointer(raw.ID)))
if err != nil {
break out
// Get the method of the request and check whether it
// should be handled by wallet or passed down to btcd.
// If the latter, handle in a new goroutine (to not
// block or be blocked by the handling of actual wallet
// requests).
//
// This is done by unmarshaling the JSON bytes into a
// rawRequest to avoid the mangling of unmarshaling and
// re-marshaling of large JSON numbers, as well as the
// overhead of unneeded unmarshals and marshals.
var raw rawRequest
if err := json.Unmarshal(request, &raw); err != nil {
if !wsc.authenticated {
// Disconnect immediately.
break out
}
err = wsc.send(marshalError(idPointer(raw.ID)))
if err != nil {
break out
}
continue
}
continue
}
f, ok := handlerFunc(raw.Method, true)
if ok || raw.Method == "authenticate" {
// unauthedRequests is buffered to the max number of
// concurrent websocket client requests so as to not
// block the passthrough of later btcd requests.
wsc.unauthedRequests <- unauthedRequest{request, f}
} else {
// websocketPassthrough is run as a goroutine to
// send an unhandled request to the chain server without
// blocking the handling of later wallet requests.
go s.websocketPassthrough(wsc, raw)
f, ok := handlerFunc(raw.Method, true)
if ok || raw.Method == "authenticate" {
// unauthedRequests is buffered to the max
// number of concurrent websocket client
// requests so as to not block the passthrough
// of later btcd requests.
wsc.unauthedRequests <- unauthedRequest{request, f}
} else {
// websocketPassthrough is run as a goroutine to
// send an unhandled request to the chain server
// without blocking the handling of later wallet
// requests.
go s.websocketPassthrough(wsc, raw)
}
case <-s.quit:
break out
}
}
close(wsc.unauthedRequests)
@ -773,8 +789,13 @@ func (s *rpcServer) WebsocketClientRPC(wsc *websocketClient) {
return
}
s.wg.Add(4)
// WebsocketClientRead is intentionally not run with the waitgroup
// so it is ignored during shutdown. This is to prevent a hang during
// shutdown where the goroutine is blocked on a read of the
// websocket connection if the client is still connected.
go s.WebsocketClientRead(wsc)
s.wg.Add(3)
go s.WebsocketClientGateway(wsc)
go s.WebsocketClientRespond(wsc)
go s.WebsocketClientSend(wsc)
@ -1044,7 +1065,15 @@ out:
jsonErr.Code = btcjson.ErrWallet.Code
}
}
r.response <- handlerResponse{result, jsonErr}
// The goroutine which requested this may not be running
// anymore. If the quit chan is read instead, break out
// of the loop now so more requests aren't potentially
// read after reentering the loop.
select {
case r.response <- handlerResponse{result, jsonErr}:
case <-s.quit:
break out
}
case <-s.quit:
break out