Я читаю исходный код MicroMDM , в частности, реализацию pollCommands
(https://github.com/micromdm/micromdm/blob/5c70048c14592fc16c2107f1af1bf8e0d3a52e0b/platform/queue/queue.go#L223 -L284 ):
func (db *Store) pollCommands(pubsub pubsub.PublishSubscriber) error {
commandEvents, err := pubsub.Subscribe(context.TODO(), "command-queue", command.CommandTopic)
if err != nil {
return errors.Wrapf(err,
"subscribing push to %s topic", command.CommandTopic)
}
go func() {
for {
select {
case event := <-commandEvents:
var ev command.Event
if err := command.UnmarshalEvent(event.Message, &ev); err != nil {
level.Info(db.logger).Log("msg", "unmarshal command event in queue", "err", err)
continue
}
cmd := new(DeviceCommand)
cmd.DeviceUDID = ev.DeviceUDID
byUDID, err := db.DeviceCommand(ev.DeviceUDID)
if err == nil && byUDID != nil {
cmd = byUDID
}
newPayload, err := plist.Marshal(ev.Payload)
if err != nil {
level.Info(db.logger).Log("msg", "marshal event payload", "err", err)
continue
}
newCmd := Command{
UUID: ev.Payload.CommandUUID,
Payload: newPayload,
}
cmd.Commands = append(cmd.Commands, newCmd)
if err := db.Save(cmd); err != nil {
level.Info(db.logger).Log("msg", "save command in db", "err", err)
continue
}
level.Info(db.logger).Log(
"msg", "queued event for device",
"device_udid", ev.DeviceUDID,
"command_uuid", ev.Payload.CommandUUID,
"request_type", ev.Payload.Command.RequestType,
)
cq := new(QueueCommandQueued)
cq.DeviceUDID = ev.DeviceUDID
cq.CommandUUID = ev.Payload.CommandUUID
msgBytes, err := MarshalQueuedCommand(cq)
if err != nil {
level.Info(db.logger).Log("msg", "marshal queued command", "err", err)
continue
}
if err := pubsub.Publish(context.TODO(), CommandQueuedTopic, msgBytes); err != nil {
level.Info(db.logger).Log("msg", "publish command to queued topic", "err", err)
}
}
}
}()
return nil
}
Что Меня удивляет, почему в for
l oop есть оператор select
с одним case
. Разве этот код не был бы эквивалентен
for {
event := <-commandEvents
var ev command.Event
...
}
Мне кажется, что код можно упростить, покончив с оператором select
?