func (re *RouterElement) run(doRouting func(*RouterElement, *Peer, [][]byte) (*Peer, [][]byte, error), controlIn, controlOut *zmq.Socket) {
var wg sync.WaitGroup
controlChanInternal := make(chan *controlMessage, 1)
wg.Add(1)
// Start a goroutine to copy from the control channel to the internal
// control channel and wake up the control socket pair on each message.
// Quit the goroutine when the control channel itself is closed
go func() {
defer func() {
controlIn.SetLinger(0)
controlIn.Close()
wg.Done()
}()
msg := [][]byte{[]byte{0}}
for {
select {
case m, ok := <-re.controlChan:
if !ok {
close(controlChanInternal)
// send a message to the control panel to wake it up
controlIn.SendMessage(msg)
// ensure we get a message back before closing it
controlIn.RecvMessageBytes(0)
return
}
controlChanInternal <- m
controlIn.SendMessageDontwait(msg)
}
}
}()
defer func() {
wg.Wait()
controlOut.SetLinger(0)
controlOut.Close()
// Close() should already remove all the peers, so this is just belt & braces
for _, p := range re.peers {
p.sock.SetLinger(0)
p.sock.Close()
close(p.buffer)
}
re.wg.Done()
}()
for {
poller := zmq.NewPoller()
pollSource := make([]*Peer, len(re.peers), len(re.peers))
blockInput := false
i := 0
for _, p := range re.peers {
pollSource[i] = p
i++
if p.xmit == nil {
select {
case p.xmit = <-p.buffer:
default:
}
}
buffered := len(p.buffer)
if p.xmit != nil {
buffered++
}
if buffered >= cap(p.buffer) {
log.Printf("Blocking input as %s cannot take more data", p.Name)
blockInput = true
}
}
for _, p := range pollSource {
flags := zmq.State(0)
if !blockInput {
flags |= zmq.POLLIN
}
if p.xmit != nil {
flags |= zmq.POLLOUT
}
poller.Add(p.sock, flags)
}
idxControl := poller.Add(controlOut, zmq.POLLIN)
if polled, err := poller.PollAll(-1); err != nil {
log.Printf("Cannot poll: %v", err)
} else {
for i, p := range pollSource {
if (polled[i].Events&zmq.POLLOUT != 0) && (p.xmit != nil) {
if _, err := p.sock.SendMessageDontwait(p.xmit); err != nil {
log.Printf("Peer %s cannot send message: %v", p.Name, err)
}
p.xmit = nil
}
}
for i, p := range pollSource {
if polled[i].Events&zmq.POLLIN != 0 {
if recv, err := p.sock.RecvMessageBytes(0); err != nil {
log.Printf("Peer %s cannot receive message: %v", p.Name, err)
} else {
if dest, fwd, err := doRouting(re, p, recv); err != nil {
log.Printf("Peer %s cannot route message: %v", p.Name, err)
} else {
if dest != nil && fwd != nil {
dest.buffer <- fwd
}
}
}
}
}
if polled[idxControl].Events&zmq.POLLIN != 0 {
// read from the control socket and discard. We don't care
// if this errors as it's really only to make us read from our
// own control socket
controlOut.RecvMessageBytes(0)
select {
case msg, ok := <-controlChanInternal:
if !ok {
// control channel is closed
// send a dummy message to handshake
msg := [][]byte{[]byte{0}}
controlOut.SendMessage(msg)
return
}
msg.reply <- re.processControlMessage(msg)
default:
}
}
}
}
}