Mosquitto config replace `message_size_limit` with `max_packet_size`

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The open edge framework for lightweight IoT devices

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Mosquitto config replace `message_size_limit` with `max_packet_size` #1491

Closed scharri closed 1 year ago

scharri commented 2 years ago

Describe the bug If you start mosquitto in verbose mode you will get the note about using max_packet_size instead message_size_limit.

To Reproduce Start mosquitto and look at the output: sudo mosquitto -v -c /etc/mosquitto/mosquitto.conf

Expected behavior No information about using an alternative option instead used option.

Screenshots 2022-10-17 12_21_16-Clipboard

Environment (please complete the following information):

OS: Debian GNU/Linux 11 (bullseye)
Hardware: Raspberry Pi 4 Model B Rev 1.4
System-Architecture: Linux raspberrypi 5.15.61-v8+ #1579 SMP PREEMPT Fri Aug 26 11:16:44 BST 2022 aarch64 GNU/Linux
thin-edge.io version: 0.7.5

Additional context

rina23q commented 2 years ago

Hi @scharri, can you tell us your mosquitto version?

scharri commented 2 years ago

Hi @rina23q my mosquitto version is: 2.0.11

reubenmiller commented 2 years ago

From first look the main differences in the docs between the settings are:

max_packet_size applies a limit the whole message (not just payload)
message_size_limit applies a limit to the message's payload size

So it looks like we can make the change (assuming all of the integration tests don't pick up anything unexpected)

reubenmiller commented 2 years ago

We might need to rethink the default value, as Cumulocity default MQTT payload limit is 16384 bytes. There is a semi-related ticket regarding this #1415

Otherwise if we did not want to impose the limit to the local MQTT broker, we could limit the bridge max package size setting via bridge_max_packet_size. But again we need to be careful about mismatches between the local and bridge MQTT brokers so that messages don't get silently swallowed without being propagated to the cloud.

didier-wenzek commented 2 years ago

Apologize: I respond to this question off-line but failed to report the response here.

max_packet_size is meaningful only for MQTT v5 while thin-edge use MQTT v3.1.1.
`message_size_limit is supported by both versions ... but requires a code change since we need then to check for any error code returned attached to the ACK messages.

So this is not a simple fix.

reubenmiller commented 1 year ago

Since we don't have short term plans to support MQTT v5 we will close this issue.