mqtt plugin: Unknown type:

[ves1820]

• Version of collectd: collectd 5.12.0
• Operating system / distribution: linux / openwrt 22.03.3
• Kernel version (if applicable): -

Expected behavior

read data from mqtt-broker and write data to RRD plugin

(Description of the behavior / output that you expected)
Subscribe is working
data received:

stat/tasmota_9292EF/RESULT {"POWER1":"off"}
stat/tasmota_9292EF/POWER1 off
stat/tasmota_9292EF/RESULT {"POWER1":"on"}
stat/tasmota_9292EF/POWER1 on

Actual behavior

the data where not recognized:

mqtt plugin: Unknown type: "RESULT".
mqtt plugin: Unknown type: "POWER1".

(Description of the behavior / output that you observed)

Steps to reproduce

• install collectd / mqtt plugin
• configure mqtt in /etc/collectd/conf.d/mqtt.conf

<Plugin "mqtt">
   <Subscribe "outdoor">
     Host "127.0.0.1"
     Topic "stat/tasmota_9292EF/#"
     CleanSession true
   </Subscribe>
</Plugin>

[eero-t]

Thanks for reporting this!

PR fixing the issue would be welcome. Otherwise it can take a long time until there's a fix for the issue.

(There are only few active developers, and they primarily look into plugins that they use / can test themselves.)

[viulian]

I would argue that this is not a bug.

The mqtt.c plugin expects to find a data set called RESULT (or POWER1) here:

  ds = plugin_get_ds(vl.type);
  if (ds == NULL) {
    ERROR("mqtt plugin: Unknown type: \"%s\".", vl.type);
    return;
  }

(for a direct link):

collectd/src/mqtt.c

Line 207 in 9369ed7

ERROR("mqtt plugin: Unknown type: \"%s\".", vl.type);

Which, means that collectd expects to find a data set called POWER1 or RESULT into types.db - which, if you just installed collectd, most likely are not defined.