The metrics endpoint

[khaaliid]

Hello, I would like to thank you for the great effort you are doing for that project.

I used this project in my setup and I was able to connect to the MQTT successfully, also I can see the metrics printed out in the logs when I enabled the debug level logging. But when I tried to access the /metrics endpoint what I get are some internal metrics ( i.e. go_gc_duration_seconds{quantile="0"} 4.5e-05 ) .. the only part I found which can be relevant to the MQTT is below 3 lines and the number at the end of the third line (13) increased whenever new metric added to the Topic. Is that expected or I have missed something in my configuration?

# HELP received_messages received messages per topic and status
# TYPE received_messages counter
received_messages{status="success",topic="mydev/3/test_metrics"} 13

Below is the config file used:

mqtt:
 server: tcp://10.51.209.100:1883
 client_id: testmqqt
 topic_path: mydev/3/test_metrics
 device_id_regex: "mydev/?(?P<deviceid>.*)/.*"
 qos: 0
cache:
 timeout: 24h
json_parsing:
 separator: .
metrics:
 - prom_name: cpu_load
   mqtt_name: cpu_load
   help: test CPU load
   type: gauge
 - prom_name: memory_usage
   mqtt_name: memory_usage
   help: test memory usage
   type: gauge

And below is the mqtt2prometheus logs :

2022-03-11T15:16:30Z info mqttclient/mqttClient.go:21 Will subscribe to topic {"topic": "mydev/3/test_metrics"}
2022-03-11T15:16:31Z debug metrics/ingest.go:42 Got message {"topic": "mydev/3/test_metrics", "payload": "{"cpu_load":95.80 ,"memory_usage":123456789678.60 }\u0000"}

Thanks ..

[khaaliid]

After searching for a while the issue is in the source system as it is giving invalid JSON format which makes the mqtt2prometheus to skip these (as you can see there is \u0000 appended in the Json string ).

[hikhvar]

Hey,
sorry for not answering in time. As you already debugged yourself, the JSON is invalid.

To answer your question on the metric received_messages. This is intended to be increased for every received message. As an operator you can use this to monitor if your monitored devices are sending messages with the expected rate. If the rate drops to low, you might want to check the sending device.