Matching outputs to inputs

Telegraf
1

I intend to have multiple [[inputs.mqtt_consumer]]'s & [[outputs.influxdb_v2]]'s, and need to ensure that each output, only processes a single matching input.
So in the example below, only topics mybridge/data/sensors will be sent to the temperature bucket.
And the same applies to other inputs & outputs.

# # output configuration for incoming mqtt msgs
 [[outputs.influxdb_v2]]
   urls = ["https://my-server:8999/"]
   token = "XYtzjexhtbFmsbk4hgGfhg34gyg34h434jggzptRQ1xBFkU4jtessb7BEbPYMQSl3uFK81o3VwJvZNQ=="
   organization = "my server"
   bucket = "temperature"

# # Read metrics from MQTT topic(s)
 [[inputs.mqtt_consumer]]
   servers = ["tcp://localhost:1883"]
   topics = ["mybridge/data/sensors",]
   topic_tag = ""
   qos = 0
   username = "zen"
   password = "mypassword"
   data_format = "json"

I’ve read other posts and the docs, but can’t get my head around namepass and how its is used, if indeed that is the correct approach…

2

You will want to use either a namepass or tagpass on the outputs, see the selectors docs

If you have two metrics for example:

metric,tag=sensor1 value=42
other,tag=sensor2 value=21

Using namepass:

# only for metrics called "metric"
[[outputs.influxdb_v2]]
  namepass = ["metric"]

# only for metrics called "other"
[[outputs.influxdb_v2]]
  namepass = ["other"]

Is that more clear? I think showing what your metrics actually look like would help if you wanted more examples.

Or using tagpass:

# only for sensor1 tagged metrics
[[outputs.influxdb_v2]]
  tagpass = {"tag" = ["sensor1"]}

# only for sensor2 tagged metrics
[[outputs.influxdb_v2]]
  tagpass = {"tag" = ["sensor2"]}
3

@jpowers - my mqtt message is an array of json objects like this;

[
  [
    {
      "temperature": 19.9,
      "humidity": 60,
      "battery": 2.9,
      "rssi": -50,
      "time": 1681312968333
    },
    {
      "tag1": "node23",
      "tag2": "sensor"
    }
  ]
]

…and have numerous similar messages using "tag2": "sensor", but the tag1 varies, such as node25, node26 etc.
All of the "tag2": "sensor" messages should be processed by the same output, but which should disregard others, such as;
{
“tag1”: “voltage”,
“tag2”: “diverter”
}

4

What is your goal? Have any tag2 = sensor to go to one output, but not others?

5

Yes. All "tag2": "sensor" to go to the one output, and eventually to the same bucket.

6

Then I would do the following:

# only metrics with tag2 == sensor go to this output
[[outputs.influxdb_v2]]
  tagpass = {"tag2" = ["sensor"]}

# everything not matching tag2 == sensor go to this output
[[outputs.influxdb_v2]]
  tagdrop = {"tag2" = ["sensor2"]}
1 Like
7

Thanks Josh, that’s clear now, and it works exactly how I hoped.
After the reading I did earlier, I think I was expecting it to be much more complicated than that, but it’s pretty straightforward really.

I appreciate your help.

1 Like