// getBroker gets or creates a broker association and returns the broker
// the first time it also starts a goroutine that receives downlink from the broker
func (r *router) getBroker(brokerAnnouncement *pb_discovery.Announcement) (*broker, error) {
// We're going to be optimistic and guess that the broker is already active
r.brokersLock.RLock()
brk, ok := r.brokers[brokerAnnouncement.Id]
r.brokersLock.RUnlock()
if ok {
return brk, nil
}
// If it doesn't we still have to lock
r.brokersLock.Lock()
defer r.brokersLock.Unlock()
if _, ok := r.brokers[brokerAnnouncement.Id]; !ok {
// Connect to the server
// TODO(htdvisser): This is blocking
conn, err := brokerAnnouncement.Dial()
if err != nil {
return nil, err
}
client := pb_broker.NewBrokerClient(conn)
association := pb_broker.NewMonitoredRouterStream(client, func() context.Context {
return r.GetContext("")
})
downlink := association.Channel()
brk := &broker{
conn: conn,
association: association,
client: client,
uplink: make(chan *pb_broker.UplinkMessage),
}
go func() {
for {
select {
case message := <-brk.uplink:
association.Send(message)
case message := <-downlink:
go r.HandleDownlink(message)
}
}
}()
r.brokers[brokerAnnouncement.Id] = brk
}
return r.brokers[brokerAnnouncement.Id], nil
}
