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From Jakub Scholz <ja...@scholz.cz>
Subject Re: Status monitoring
Date Sun, 14 Jan 2018 14:12:08 GMT
How do you plan to implement this: "Before the shutdown the sensor remove
its entry from the queue."?

If you plan to have large amount of sensors (= a lot of messages in the
StatusOverview queue) which would shutdown often, finding and accepting the
particular message might not be the optimal way to do this. So maybe you
can instead send a message which would contain in the properties or body
the information that the sensor is shutting down. It would overwrite the
previous status and later expire and be removed automatically.

Regards
Jakub

On Sun, Jan 14, 2018 at 2:46 PM, Daniel Gavrila <d.gavrila@icloud.com>
wrote:

>
> These are good news!
> I think I'm able now to translate the use case scenario in "AMQP  language"
>
> Each sensor publish a durable message with TTL=N seconds to the LVQ
> durable queue StatusOverview  every N seconds.
> Each GUI  client read the queue OverviewStatus in browse mode.
> Before the shutdown the sensor remove its entry from the queue.
> If a abnormal exit occurs the queue will remove the entry after maxim N
> seconds
>
> I have one more general question. Which relation is between qpid-config
> and the qpid::messaging API ? Everything that can be done with qpid-config
> can be done also with the API ?
>
> Best regards,
> Daniel
>
>
> > On 13.01.2018, at 17:23, Jakub Scholz <jakub@scholz.cz> wrote:
> >
> > The LVQ queue is able to persist these messages to disk like any other
> > queue. So they can survive restart.
> >
> > Jakub
> >
> > On Sat, Jan 13, 2018 at 4:55 PM, Daniel Gavrila <d.gavrila@icloud.com>
> > wrote:
> >
> >> Hello Andreas,
> >>
> >> Thanks for the suggestion.From what I read from documentation, indeed a
> >> last value queue should cover a signifiant part of use case
> >> scenario.Remains the question if the values from a LVQ could be make
> >> persistent, so that will be recovered after a broker restart?
> >>
> >> Best regards,
> >> Daniel
> >>
> >>
> >>> On 13.01.2018, at 12:55, Andreas Welchlin <andreas@welchlin.de> wrote:
> >>>
> >>> Hello Daniel,
> >>>
> >>> this should work using a last value queue.
> >>>
> >>> Kind Regards,
> >>> Andreas
> >>>
> >>> Am 13. Januar 2018 12:19:57 MEZ schrieb Daniel Gavrila <
> >> d.gavrila@icloud.com>:
> >>>>
> >>>>
> >>>> Hello,
> >>>>
> >>>> My environment is:
> >>>>     C++ Proton v. 0.19
> >>>>     C++ Broker v.1.37 configured with AMQP 1.0
> >>>>
> >>>> I have to implement the following use case scenario. The network
> >> contains N publishers(sensors) . When one sensor starts it publish to
> the
> >> queue OverviewStatus one message that contains some data: sensor
> >> name,type,internal status etc. One GUI program has to display the
> >> information from the queue OverviewStatus. Everytime the sensor changes
> its
> >> internal status he needs to update the status in the queue.Before the
> >> shutdown , the sensor has to remove its entry from the queue.
> >>>> If the sensor exits anormaly the event should be catched and the
> sensor
> >> status modified accordingly. By restarting the broker, all the sensors
> >> status information should be recovered.
> >>>>
> >>>> Is it possibly to implement such use case in the above mentioned
> >> environment? Any suggestions are welcomed !
> >>>>
> >>>> Many thanks,
> >>>> Daniel
> >>
>

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