Race condition #168
Description
version 1.7.2, Go 1.3
It seems a race is triggered when calling close and waiting for a read: https://github.com/andersfylling/disgord/commit/d57507037a8b0f9d506d8940c99066e55f8ceecf/checks?check_suite_id=293975922
complete output:
==================
WARNING: DATA RACE
Write at 0x00c00000c510 by goroutine 49:
nhooyr.io/websocket.(*Conn).reader()
/home/runner/go/pkg/mod/nhooyr.io/websocket@v1.7.2/conn.go:443 +0x2ef
nhooyr.io/websocket.(*Conn).waitClose()
/home/runner/go/pkg/mod/nhooyr.io/websocket@v1.7.2/conn.go:962 +0x3fd
nhooyr.io/websocket.(*Conn).writeClose()
/home/runner/go/pkg/mod/nhooyr.io/websocket@v1.7.2/conn.go:928 +0x330
nhooyr.io/websocket.(*Conn).exportedClose()
/home/runner/go/pkg/mod/nhooyr.io/websocket@v1.7.2/conn.go:888 +0x263
nhooyr.io/websocket.(*Conn).Close()
/home/runner/go/pkg/mod/nhooyr.io/websocket@v1.7.2/conn.go:856 +0x7c
github.com/andersfylling/disgord/internal/gateway.(*nhooyr).Close()
...
Previous read at 0x00c00000c510 by goroutine 78:
nhooyr.io/websocket.(*messageReader).read()
/home/runner/go/pkg/mod/nhooyr.io/websocket@v1.7.2/conn.go:482 +0xc4e
nhooyr.io/websocket.(*messageReader).Read()
/home/runner/go/pkg/mod/nhooyr.io/websocket@v1.7.2/conn.go:468 +0x66
bytes.(*Buffer).ReadFrom()
/opt/hostedtoolcache/go/1.13.4/x64/src/bytes/buffer.go:204 +0x158
io/ioutil.readAll()
/opt/hostedtoolcache/go/1.13.4/x64/src/io/ioutil/ioutil.go:36 +0x13e
nhooyr.io/websocket.(*Conn).Read()
/opt/hostedtoolcache/go/1.13.4/x64/src/io/ioutil/ioutil.go:45 +0x101
github.com/andersfylling/disgord/internal/gateway.(*nhooyr).Read()
...I'm unable to copy the complete output, but it should be found in the link given. The reason you see multiple of these is as I have 4 websockets I'm trying to close.
See previous issue, that I thought I had fixed (single websocket connection): andersfylling/disgord#236
Some of the error messages returned from the Read method of your lib was:
- cannot use EOFed reader
- failed to read frame payload: unexpected EOF
Is this happening because I try to execute a Read after a close? I understand it as your lib dispatches a close such that the Read method will not block. I just can't figure out, right now why I would be reading twice.
internal, cancel := context.WithCancel(context.Background())
for {
// check if application has closed
select {
case <-ctx.Done():
c.log.Debug(c.getLogPrefix(), "closing receiver")
return
case <-internal.Done():
go c.reconnect()
c.log.Debug(c.getLogPrefix(), "closing receiver after read error")
return
default:
}
var packet []byte
var err error
if packet, err = c.conn.Read(context.Background()); err != nil {
cancel()
continue
}My disconnect method might call Close twice.
I'm a bit baffled; I've been trying to fix this for a while and as this hasn't been an issue before, so I'm sure I've done something weird. I'm asking here, hoping, that you might have an idea what to look for(?) as I'm struggling to reproduce this issue consistently.