// SubscribeCommand() function updates the command.
func (service *Service) SubscribeCommands(device *core.Device, timestamp string, timeout time.Duration) (listener *core.CommandListener, err error) {
task, err := service.prepareSubscribeCommand(device, timestamp)
if err != nil {
log.Warnf("WS: failed to prepare /command/subscribe task (error: %s)", err)
return
}
// add to the TX pipeline
service.tx <- task
select {
case <-time.After(timeout):
log.Warnf("WS: failed to wait %s for /command/subscribe task", timeout)
err = fmt.Errorf("timed out")
case <-task.done:
err = service.processSubscribeCommand(task)
if err != nil {
log.Warnf("WS: failed to process /command/subscribe task (error: %s)", err)
return
}
// done, create listener
listener = core.NewCommandListener()
service.insertCommandListener(device.Id, listener)
}
return
}
// subscribe for commands
func (service *Service) SubscribeCommands(device *core.Device, timestamp string, timeout time.Duration) (listener *core.CommandListener, err error) {
if listener, ok := service.commandListeners[device.Id]; ok {
return listener, nil
}
// install new
listener = core.NewCommandListener()
service.commandListeners[device.Id] = listener
go func(deviceId string) {
log.Debugf("REST: start command polling %q", deviceId)
for {
names := ""
wait := "30"
cmds, err := service.PollCommands(device, timestamp, names, wait, 60*time.Second)
if err != nil {
log.Warnf("REST: failed to poll commands (error: %s)", err)
// TODO: break? wait and try again?
}
if listener, ok := service.commandListeners[deviceId]; ok {
for _, cmd := range cmds {
log.Debugf("REST: got command %s received", cmd)
timestamp = cmd.Timestamp
listener.C <- &cmd
}
} else {
log.Debugf("REST: stop command polling %q", deviceId)
return // stop
}
}
}(device.Id)
return
}