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1.5.8-0: $SYS Subscription Wildcards [message #1805260]

Wed, 10 April 2019 13:51

Rial Williams

Messages: 2
Registered: April 2019

Junior Member

I have two brokers (both 1.5.8-0) I'm working with. One running on a local Raspberry Pi collecting data and it bridges all data to a remote Linux LAMP server (UbuntuServer). The local mosquitto.conf file has line "topic $SYS/broker/uptime in 0 UbuntuServer/ """ in it which says that the local broker subscribes to the remote bridged broker $SYS/broker/uptime" topic which I use to monitor the local connection to the remote broker (UbuntuServer). At the local broker, if I subscribe to "UbuntuServer/#" I see "UbuntuServer/$SYS/broker/uptime" topic show up regularly with the proper data in it. If I subscribe to "UbuntuServer/$SYS/#" or any more granular topic, nothing shows up. I see this behavior in the program I'm working with and also with a generic MQTT client (MQTT.fx) running on my Windows laptop. I was running mosquitto 1.5.3 until recently and I never noticed this behavior before. Has anyone seen this behavior? Is this something specific to $SYS topics? Thanks so much in advance.

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Re: 1.5.8-0: $SYS Subscription Wildcards [message #1805419 is a reply to message #1805260]

Mon, 15 April 2019 07:21

Roger Light

Messages: 90
Registered: September 2013

Member

What is happening here is that you have the bridge configured to just receive the $SYS/broker/uptime topic. If you want to have more things appear on the local broker then you will need to change the bridge topic subscription to something like "topic $SYS/broker/# ..."

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Re: 1.5.8-0: $SYS Subscription Wildcards [message #1805466 is a reply to message #1805419]

Mon, 15 April 2019 16:06

Rial Williams

Messages: 2
Registered: April 2019

Junior Member

Maybe I wasn't clear. Yes, I know I have only subscribed to a single topic ("$SYS/broker/uptime") coming from the remote broker. In the local broker, "UbuntuServer/" is prepended to it. That's what I want. At the local broker, if I subscribe to "UbuntuServer/#", I see what I'm after, but if I subscribe to "UbuntuServer/$SYS/#" I see nothing. This doesn't seem right.

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