// Signal counterpart of Signl-Slot design pattern.
func (g *Gilmour) Signal(topic string, msg *Message) (sender string, err error) {
if msg == nil {
msg = NewMessage()
}
sender = proto.SenderId()
msg.setSender(sender)
return sender, g.publish(g.slotDestination(topic), msg)
}
// Request part of Request-Reply design pattern.
func (g *Gilmour) request(topic string, msg *Message, opts *RequestOpts) (*Response, error) {
if has, err := g.backend.HasActiveSubscribers(g.requestDestination(topic)); err != nil {
return nil, err
} else if !has {
return nil, errors.New("No active listeners for: " + topic)
}
if msg == nil {
msg = NewMessage()
}
sender := proto.SenderId()
msg.setSender(sender)
respChannel := proto.ResponseTopic(sender)
if opts == nil {
opts = NewRequestOpts()
}
//Wait for a responseHandler
f := make(chan *Message, 1)
rOpts := NewHandlerOpts().setOneShot().sendResponse(false)
g.ReplyTo(respChannel, func(req *Request, _ *Message) {
f <- req.gData
}, rOpts)
// Send Timeout message to channel, Need to send timeout over the wire,
// to ensure gilmour cleans up the oneShot response handlers as well.
timeout := opts.GetTimeout()
if timeout > 0 {
time.AfterFunc(time.Duration(timeout)*time.Second, func() {
g.sendTimeout(sender, respChannel)
})
}
g.publish(g.requestDestination(topic), msg)
response := newResponse(1)
response.write(<-f)
return response, nil
}
func NewMessage() *Message {
x := &Message{}
x.setSender(proto.SenderId())
return x
}
