// Internal method to publish a message.
func (g *Gilmour) publish(topic string, msg *Message) error {
if msg.GetCode() == 0 {
msg.SetCode(200)
}
if msg.GetCode() >= 300 {
go func() {
request, err := msg.Marshal()
if err != nil {
request = []byte{}
}
g.reportError(
proto.MakeError(
msg.GetCode(), topic, string(request), "", msg.GetSender(), "",
),
)
}()
}
sent, err := g.backend.Publish(topic, msg)
if err != nil {
return err
} else if !sent {
return errors.New(fmt.Sprintf("Mesage for %v was not received by anyone.", topic))
} else {
return err
}
}
func (g *Gilmour) handleRequest(s *Subscription, topic string, m *Message) {
senderId := m.GetSender()
req := &Request{topic, m}
res := NewMessage()
res.setSender(proto.ResponseTopic(senderId))
done := make(chan bool, 1)
//Executing Request
go func(done chan<- bool) {
// Schedule a function to recover in case handler runs into an error.
// Read more: https://gist.github.com/meson10/d56eface6f87c664d07d
defer func() {
err := recover()
if err == nil {
return
}
const size = 4096
buf := make([]byte, size)
buf = buf[:runtime.Stack(buf, false)]
buffer := string(buf)
res.SetData(buffer).SetCode(500)
done <- true
}()
s.GetHandler()(req, res)
done <- true
}(done)
// Start a timeout handler, which writes on the Done channel, ahead of the
// handler. This might result in a RACE condition, as there is no way to
// kill a goroutine, since they are not preemptive.
timeout := s.GetOpts().GetTimeout()
time.AfterFunc(time.Duration(timeout)*time.Second, func() {
done <- false
})
status := <-done
if s.GetOpts().shouldSendResponse() {
if status == false {
g.sendTimeout(senderId, res.GetSender())
} else {
if res.GetCode() == 0 {
res.SetCode(200)
}
if err := g.publish(res.GetSender(), res); err != nil {
ui.Alert(err.Error())
}
}
} else if status == false {
// Inform the error catcher, If there is no handler for this Request
// but the request had failed. This is automatically handled in case
// of a response being written via Publisher.
request := string(req.bytes())
errMsg := proto.MakeError(499, topic, request, "", req.Sender(), "")
g.reportError(errMsg)
}
}