Buffering messages with connection lost on thin-edge.io

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Hi all,
how thin-edge framework is handling lost of connection? Is there any plugin to persist MEAs and send them to cloud as connectivity is up, or which would be the right way to do that?

thanks

Mauro

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Hi Mauro,

thin-edge.io uses a local MQTT broker with a bridged connection to the Cumulocity IoT MQTT endpoint. MQTT has the QoS functionality which is used for buffering messages:
0 - at most once (fire and forget - no buffering on client side)
1 - at least once (make sure it is received at least once - buffering until ack is received from at least on recipient)
2 - exactly once (make sure it is only received once - buffering until exactly one recipient acknowledges)

You should use QoS 1 or QoS 2 when you want to make sure the messages are cached. QoS 1 is preferred over QoS 2 due to high performance cost of 2.
So when using the pre-defined c8y topics with correlated QoS thin-edge will take care of buffering.

Also when having a high message throughput with repeatable non-critical values like measurements maybe QoS 0 is sufficient.

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