Robert Munteanu created SLING-12013: ---------------------------------------
Summary: Commons Threads export invalid 'Pid' attribute as gauge Key: SLING-12013 URL: https://issues.apache.org/jira/browse/SLING-12013 Project: Sling Issue Type: Bug Components: Commons Reporter: Robert Munteanu Assignee: Robert Munteanu Fix For: Commons Threads 3.3.0 The commons.thread bundle exports its JMX attributes as Gauges via the [ThreadPoolMetricGauges class](https://github.com/apache/sling-org-apache-sling-commons-threads/blob/master/src/main/java/org/apache/sling/commons/threads/impl/ThreadPoolMetricsGauges.java). In particular, it also exports the 'Pid' attribute. This attribute does not make sense as a Gauge value ( it's a static, non-numeric, value ) and when exported ends up null. When used with the [prometheus bundle from the whiteboard](https://github.com/apache/sling-whiteboard/tree/master/metrics-prometheus) it breaks the Prometheus metric servlet, causing no metrics to be returned. Note that this is the code provided by the Prometheus SimpleClient bundle, we can't influence how it behaves. I tried. {noformat} 29.08.2023 17:42:16.461 *ERROR* [FelixLogListener] LogService.org.apache.felix.http.jetty Exception while processing request to /metrics (java.lang.NullPointerException: Cannot invoke "Object.getClass()" because "obj" is null) java.lang.NullPointerException: Cannot invoke "Object.getClass()" because "obj" is null at io.prometheus.client.dropwizard.DropwizardExports.fromGauge(DropwizardExports.java:55) [io.prometheus.simpleclient_dropwizard:0.0.23] at io.prometheus.client.dropwizard.DropwizardExports.collect(DropwizardExports.java:133) [io.prometheus.simpleclient_dropwizard:0.0.23] at io.prometheus.client.CollectorRegistry$MetricFamilySamplesEnumeration.findNextElement(CollectorRegistry.java:180) [io.prometheus.simpleclient:0.0.23] at io.prometheus.client.CollectorRegistry$MetricFamilySamplesEnumeration.<init>(CollectorRegistry.java:144) [io.prometheus.simpleclient:0.0.23] at io.prometheus.client.CollectorRegistry.filteredMetricFamilySamples(CollectorRegistry.java:131) [io.prometheus.simpleclient:0.0.23] at io.prometheus.client.exporter.MetricsServlet.doGet(MetricsServlet.java:43) [io.prometheus.simpleclient_servlet:0.0.23] at javax.servlet.http.HttpServlet.service(HttpServlet.java:655) [org.apache.felix.http.servlet-api:1.2.0] at javax.servlet.http.HttpServlet.service(HttpServlet.java:764) [org.apache.felix.http.servlet-api:1.2.0] {noformat} -- This message was sent by Atlassian Jira (v8.20.10#820010)