Thanks Guys for quick support.
Regards
Pankaj
From: paho-dev-bounces@xxxxxxxxxxx <paho-dev-bounces@xxxxxxxxxxx>
On Behalf Of Andy Stanford-Clark
Sent: Thursday, October 15, 2020 3:59 PM
To: General development discussions for paho project <paho-dev@xxxxxxxxxxx>
Cc: paho-dev-bounces@xxxxxxxxxxx; Paul, Base V <base_paul@xxxxxxxxxx>
Subject: Re: [paho-dev] [ EXTERNAL ] Re: End-to-end response
MQTT QoS works "hop by hop", so a QoS 2 message will travel at QoS 2 from publisher to broker 1, and then from broker 1 to broker 2, and then from bnroker 2 to the subscriber.
There is no way for the publisher to know, at the protocol level, whether it has successfully moved beyond the broker to which it is connected (broker 1).
The only way to do this is at the application level...
The receiving application would publish an acknowledgement back on a topic on which the original sender is listening.
If you need to know that it's got to the last *broker* but not necessarily received by the final subscriber, you could perhaps run a little application on the broker machine which subscribes to and
acknowledges all messages (at the application level), which would confirm it had got to the broker box, but not yet necessarily delivered to the final destination subscriber.
Andy
Andy Stanford-Clark
IBM CTO - UK and Ireland
Distinguished Engineer, Master Inventor, IBM Quantum Ambassador,
Member IBM Academy of Technology, Fellow BCS
Visiting Professor at Newcastle, Southampton and UEA.
Tel: +44 (0)7801 787096 [internal: 37 277624] twitter: @andysc
From: "Kumar, Pankaj" <pankaj_kumar2@xxxxxxxxxx>
To: General development discussions for paho project <paho-dev@xxxxxxxxxxx>,
"Paul, Base V" <base_paul@xxxxxxxxxx>
Date: 15/10/2020 08:21
Subject: [EXTERNAL] Re: [paho-dev] [ EXTERNAL ] Re: End-to-end response
Sent by: paho-dev-bounces@xxxxxxxxxxx
+ Base Paul. From: Kumar, Pankaj Sent: Thursday, October 15, 2020 12:48 PM To:...
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+ Base Paul.
From: Kumar, Pankaj
Sent: Thursday, October 15, 2020 12:48 PM
To: General development discussions for paho project <paho-dev@xxxxxxxxxxx>
Subject: RE: [ EXTERNAL ] Re: [paho-dev] End-to-end response
Thanks for the quick response.
Let me add some more detail here.
Our ultimate aim is to track the delivery of messages to right most Broker in a reliable way.
My current setup is as following. (No issues here)
Client ---------- Broker ----------- Server
-
Client sends QOS2 message to Broker.
-
Broker sends response(PUBCOMP) back to Client
-
Transaction completes
Note: We don’t care how Broker forwards that message further to Server
Now, we have added another Broker in between as following.
Client ------------ Intermediate Broker ------------ Broker ---------- Server
-
Client sends QOS2 message to Intermediate Broker
-
Intermediate Broker sends response (PUBCOM) back to Client
-
Client can’t mark transaction complete as there is no reliable way to know when message is delivered to right most Broker.
Looking for a solution to help Client track the response from final broker. Again we don’t care how final/right-most broker further forwards that message to Server.
Regards
Pankaj
From:
paho-dev-bounces@xxxxxxxxxxx <paho-dev-bounces@xxxxxxxxxxx>
On Behalf Of Dominik Obermaier
Sent: Thursday, October 15, 2020 12:20 PM
To: General development discussions for paho project <paho-dev@xxxxxxxxxxx>
Subject: [ EXTERNAL ] Re: [paho-dev] End-to-end response
[ EXTERNAL ]
Hi Pankaj,
MQTT 5 has a concept called "Request
/ Response Pattern" that will do exactly what you want.
However, it seems you are bridging MQTT brokers. Depending on the broker you're using this might not work as not all brokers support MQTT 5 for bridging. Last time I checked mosquitto for example
did not yet have MQTT 5 support for bridges.
Best,
Dominik
On 15 Oct 2020, at 7:59, Kumar, Pankaj wrote:
Hello Dev,
Is there a way to get end-to-end response from a server which is two brokers away from client ?
Client ----------- Broker-1 ----------------Broker-2--------------Server
Looking for MQTT level solution without application level topic/messaging. I am using MQTT-5.
Regards
Pankaj
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