Unable to extract labels from loki sink in vector

[surekha3]

Trying to collect kafka logs using vector latest version and sending to loki. But unable to extract any labels from loglines. when given under labels i.e.,
labels:
env: "{{ env }}"
It's stating function env not found error though it's present within logline. Please help asap

[surekha3]

any help please

[surekha3]

Below is the sink config I used

 transforms:
    extract_transform:
      type: remap
      inputs:
        - kafka_logs
      source: |
              .topic = to_string!(.topic)
              . = parse_json!(.message)
              .host = .parsed.tags.host
  sinks:
    loki_sink:
      type: loki
      inputs:
        - extract_transform
      endpoint: http://loki-nob-gateway
      encoding:
        codec: "json"
      compression: none
      healthcheck: false
      labels:
        job: "kafka"
        topic: "{{ topic }}"
        host: "{{ host }}"

With this giving error function topic not defined and function host not defined though they're appearing in loglines when printed to console. Logs source is kafka

[pront]

Please take a look at our debugging guide: https://vector.dev/guides/developer/debugging/debugging/

This will you help gain confidence in the events and their format as they go through the pipeline. Are the events conforming to what loki expects?

[surekha3]

@pront Thanks for responding. I already able to fix this. But strange thing is no where defined in vector documents about labels exposure for loki sink. Found in grafana labs community
Below should be the way in exposing labels in loki sink
sinks:
loki_sink:
type: loki
inputs:
- extract_transform
endpoint: http://loki-nob-gateway
encoding:
codec: json
labels:
topic: "{{{{topic}}}}"
region: "{{{{region}}}}"
job: "{{{{job}}}}"