[SOLR-16137] prometheus_exporter configuration generates duplicated values for 1 metric

• Type: Bug
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Affects Version/s: 8.11.1
• Component/s: contrib - prometheus-exporter
• Labels: configuration metrics prometheus
• Assignee: Unassigned
• Reporter: César Fuentes
• Created: 01/Apr/22 10:34
• Updated: 04/May/23 17:48

Description

The prometheus-exporter comes with a default configuration in the file `solr_exporter_config.xml`. It seems that the `jq` configuration to parse metrics from Solr to Prometheus has a small bug for one metric:

In the selection done for `solr_metrics_core_requests_total`, the condition assumes that there will be 1 result, but there are actually 3 because there are these paths in the JSON (for a given core):

"QUERY./select.requestTimes"
"QUERY./select.local.requestTimes"
"QUERY./select.distrib.requestTimes"

and the selection is done like:

$jq:core(requests_total, select(.key | endswith(".requestTimes")) | select (.value | type == "object"), count) 

The generated Prometheus metrics have the same name and set of labels, thus they are identical for Prometheus and trigger a "duplicated metric" error further in the processing.

 

A simple solution is to fix the select condition, like:

$jq:core(requests_total, select(.key | endswith(".requestTimes") and (contains(".local.") or contains(".distrib.") | not)) | select (.value | type == "object"), count) 

(assuming that we want the total requestTimes count).