Dynamic relabelling only sets one last target_label

[bookwar]

What did you do?
Following example in #2078 I have a Nomad service which is scraped from Consul with
__meta_consul_tags = ,label-env-dev,label-project-myproject,label-team-myteam,

Then the following relabeling rules are applied:

      - source_labels: [__meta_consul_tags]
        regex: '.*,label-([[:alnum:]]+)-([^,]+),.*'
        replacement: '${2}'
        target_label: '${1}'

What did you expect to see?

Labels env=dev, project=myproject and team=myteam

What did you see instead?

Only the last label is applied: team=myteam

Environment

• Prometheus version:
  latest image from docker hub docker.io/prom/prometheus
  version="(version=2.0.0, branch=HEAD, revision=0a74f98628a0463dddc90528220c94de5032d1a0)"

[brian-brazil]

That's how regular expression work. See https://www.robustperception.io/extracting-full-labels-from-consul-tags/

It makes more sense to ask questions like this on the prometheus-users mailing list rather than in a GitHub issue. On the mailing list, more people are available to potentially respond to your question, and the whole community can benefit from the answers provided.

[bookwar]

I misread the #2078 then, and expected different result from it.

Thanks for the link, it works indeed.

- source_labels: [__meta_consul_tags]
        regex: ',(?:[^,]+,){0}label-([[:alnum:]]+)-([^,]+),.*'
        replacement: '${2}'
        target_label: '${1}'
      - source_labels: [__meta_consul_tags]
        regex: ',(?:[^,]+,){1}label-([[:alnum:]]+)-([^,]+),.*'
        replacement: '${2}'
        target_label: '${1}'
      - source_labels: [__meta_consul_tags]
        regex: ',(?:[^,]+,){2}label-([[:alnum:]]+)-([^,]+),.*'
        replacement: '${2}'
        target_label: '${1}'
      - source_labels: [__meta_consul_tags]
        regex: ',(?:^,]+,){3}-(label-[[:alnum:]]+)-([^,]+),.*'
        replacement: '${2}'
        target_label: '${1}'

[lock]

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