Adding fields to metrics doesnt work, only updating existing one.

[robinpecha]

Hi, I have following config where I need to add some fields to metric.

sources:
   hostmetrics_local:
    type: host_metrics
    scrape_interval_secs: 30

transforms:
  host_metrics_local_remap:
    inputs: [ "hostmetrics_local" ]
    type: "remap"
    source: |
      .namespace = "my_company"
      .maintainer = "maintainer"
      .source_cat = "source_cat"

sinks:
  blackhole:
    type: blackhole
    inputs: 
      - host_metrics_local_remap

And this is output from vector tap, no fields was added, only namespace was updated.

{"name":"load5","namespace":"my_company","tags":{"collector":"load","host":"be7de7baa9db"},"timestamp":"2025-01-07T14:51:11.606623331Z","kind":"absolute","gauge":{"value":0.2490234375}}

Please how to add fields to metrics?
Thank you.

[robinpecha]

Ok, just found this #21994 so I have my answer.
You was pointing to https://vector.dev/docs/about/under-the-hood/architecture/data-model/metric/#tags and there are some labels

in metric event. But no documentation about labels in whole text

So its possible to add some custom values via labels with remap? Or how to do it?

[pront]

Hi @robinpecha, please take a look at https://vector.dev/docs/about/under-the-hood/architecture/data-model/metric/. Unlike logs, metrics are structured events with specific fields. You can add .tags to them for example but you cannot add arbitrary fields like . maintainer.

[robinpecha]

Ok, problem solved:

  host_metrics_local_remap:
    inputs: [ "hostmetrics_local" ]
    type: "remap"
    source: |
      .namespace = "namespace"
      .tags.environment = "environment"
      .tags.datacenter = "datacenter"
      .labels.maintainer = "maintainer"
      .labels.service = "service"

Tags works, Labels not. Tags are enough for now .)

{"name":"network_transmit_packets_drop_total","namespace":"namespace","tags":{"collector":"network","datacenter":"datacenter","device":"eth0","environment":"environment","host":"be7de7baa9db"}, "timestamp":"2025-01-07T15:14:40.902959633Z","kind":"absolute","counter":{"value":0.0}}