Skip to main content

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [List Home]
Re: [mosquitto-dev] libmosquitto outgoing queue request for comment

My quick reaction is that this is jumping to a very complicated approach
and skipping over intermediate ones that are likely to be sufficient for
most cases.

I'm really unclear on when people decide to use qos 0/1/2 and why,
because there are dreadfully few protocol specs published (at least that
I have seen) that define the actual protocol used for communication over

Overall, I would lean to having queuing be optional, with configurable

  limit on # of queued messages (default 128?)

  configurable if a publish on a topic will replace the previous
  stored-and-not-yet-sent message on that same topic

Here, the big question is if there's a desire for every message to be
delivered, perhaps because it has json with a time and a value, or if
only the latest is useful, because it's just a value.   That then leads
to questions about choice of qos and persisting mesages to stable
storage so that they can survive not only broker disconnect but also
local reboot or power loss, and by the time you are done then perhaps
you should instead construct a reliable transfer protocol that uses MQTT
like UDP.

So to evaluate your proposal I'd like pointers to protocol specs of
"send this data via MQTT".  (It is both a plus and a minus of MQTT that
you can sort of get away with not defining that.)


Attachment: signature.asc
Description: PGP signature

Back to the top