[SOLR-14837] prometheus-exporter: different metrics ports publishes mixed metrics

• Type: Improvement
• Status: Patch Available
• Priority: Minor
• Resolution: Unresolved
• Affects Version/s: 8.6.2
• Component/s: contrib - prometheus-exporter
• Assignee: Unassigned
• Reporter: Fadi Mohsen
• Created: 07/Sep/20 11:20
• Updated: 22/Nov/20 21:49

Description

when calling SolrExporter.main "pro-grammatically"/"same JVM" with two different solr masters asking to publish the metrics on two different ports, the metrics are being mixed on both metric endpoints from the two solr masters.

This was tracked down to a static variable called defaultRegistry:
https://github.com/apache/lucene-solr/blob/master/solr/contrib/prometheus-exporter/src/java/org/apache/solr/prometheus/exporter/SolrExporter.java#L86

removing the static keyword fixes the issue.