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This repository was archived by the owner on Nov 10, 2020. It is now read-only.
Client.Ping method raises network disconnection: "use of closed network connection" #27
Description
STEPS TO REPRODUCE
$ cd $GOPATH/src/github.com/surgemq/surgemq/examples/surgemq
$ go run *.go
then, go run this code with -logtostderr -vv 3:
package main
import (
"flag"
"log"
"github.com/surgemq/message"
"github.com/surgemq/surgemq/service"
)
func main() {
flag.Parse()
c := &service.Client{}
cmsg := message.NewConnectMessage()
cmsg.SetVersion(4)
cmsg.SetCleanSession(true)
cmsg.SetKeepAlive(10)
if err := c.Connect("tcp://localhost:1883", cmsg); err != nil {
log.Fatalln("Connect:", err)
}
fn := func(msg, ack message.Message, err error) error {
log.Println("Pong:", err)
return err
}
done := make(chan struct{})
if err := c.Ping(service.OnCompleteFunc(fn)); err != nil {
log.Fatalln("Ping:", err)
close(done)
}
<-done
}
RESULTS
I1204 23:16:44.348778 13936 sendrecv.go:103/sender] (1/) Starting sender
I1204 23:16:44.348781 13936 process.go:46/processor] (1/) Starting processor
I1204 23:16:44.348883 13936 sendrecv.go:58/receiver] (1/) Starting receiver
I1204 23:16:44.349183 13936 service.go:210/stop] (1/) closing this.conn
I1204 23:16:44.349223 13936 sendrecv.go:100/func1] (1/) Stopping sender
E1204 23:16:44.349252 13936 sendrecv.go:76/receiver] (1/) error reading from connection: read tcp [::1]:61472->[::1]:1883: use of closed network connection
I1204 23:16:44.349364 13936 sendrecv.go:55/func1] (1/) Stopping receiver
I1204 23:16:44.349375 13936 service.go:220/stop] (1/) Received 16 bytes in 2 messages.
I1204 23:16:44.349383 13936 service.go:221/stop] (1/) Sent 6 bytes in 2 messages.
REASONS
In case of Client.Ping(), ackmsg.Msgbuf is empty in service.processAcked().
As a result, msg.Decode(ackmsg.Msgbuf) panics with "slice bounds out of range".
Activity
ankoh commentedon Jan 6, 2016
Yep I saw that as well a while ago in your code. The problem is, that a closing socket does NOT return EOF but *net.OpError.
More information can be found here:
http://comments.gmane.org/gmane.comp.lang.go.general/76607
I decided to go for this dirty hack that was proposed in the googlegroups:
jcw commentedon Jan 20, 2016
+1
Same issue here, and the IsEOF mentioned above fixes it for me as well. I changed 2 cases in sendRecv.go and 2 more in process.go - from what I can tell, the current surgemq HEAD won't work without this workaround (this is on Mac OSX 10.11.2 with Go 1.5.3, FWIW).
zhenjl commentedon Jan 25, 2016
Thanks @jcw @ankoh ... Would either of you be willing to submit a PR?
godblesshugh commentedon Nov 7, 2016
here is a discussion for that error: errClosing.
and maybe
oerr, ok := err.(*net.OpError)is not necessary, just need
if err.Error() == "use of closed network connection" { return true }as @ankoh said.
godblesshugh commentedon Nov 7, 2016
sorry.
if err.Error() == "use of closed network connection" { return true }is not necessary, need
oerr, ok := err.(*net.OpError)lufia commentedon Apr 4, 2020
Unfortunately this repo is labeled as Unmaintained. I will reopen the issue if the status comes back to Maintained.