Federation does not pass empty labels

[pieterdejaeghere]

On a local prometheus server, if a metric exists with an empty label it shows up like this:

metricxyz{empty_label="", other_label="xyz"}

if another prometheus server pulls in this metric via federation, the result becomes:

metricxyz{other_label="xyz"}

I'd expect the result to be identical, being:
metricxyz{empty_label="", other_label="xyz"}

Environment

• System information:

Redhat7 Linux 3.10.0-514.10.2.el7.x86_64 x86_64

• Prometheus version:

prometheus, version 2.0.0 (branch: HEAD, revision: 0a74f98)
build user: root@615b82cb36b6
build date: 20171108-07:11:59
go version: go1.9.2

• Prometheus configuration file:

  • job_name: federation
    scheme: http
    metrics_path: /federate
    scrape_interval: 300s
    scrape_timeout: 120s
    honor_labels: true
    params:
    'match[]':
    - '{job="xyz"}'
    static_configs:
    • targets:
      • 'other-server:9090'

[brian-brazil]

An empty label is the same thing as no label.

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.

[lock]

This thread has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.