How to add a label to a target in Prometheus using Spring boot? - spring

Question

I'm trying to add a label to a target in Prometheus modifying files in SpringBoot.
I tried adding a Prometheus label in Springboot the way below (modifying application.yml in SpringBoot), but it didn't work.
management:
metrics:
tags:
application: ${spring.application.name}
threadLimitInPrometheus: 40 # This tag didn't work
Could you let me know any way to add a Prometheus label in SpringBoot?
I know there is a way to add a new label to a target modifying prometheus.yml the way below
- target_label: "foo"
replacement: "bar"
However, I'd like to find ways in SpringBoot, not Prometheus.
Thank you.

Answer 1

There are several ways to define tags.
Common tags could be defined in application.yml
management:
metrics:
tags:
key2: value2
In case it doesn't work make sure that configuration is applied. You can run your service locally and use http://localhost:<port>/actuator/prometheus to check exposed metrics.
As an alternative you can
use MeterRegistryCustomizer
#Configuration
public class MeterRegistryConfiguration {
#Bean
public MeterRegistryCustomizer<MeterRegistry> metricsCommonTags() {
return (registry) -> registry.config().commonTags("key2", "value2");
}
}
If you need to define tags for specific metrics only, use MeterFilter
#Bean
public MeterFilter customMeterFilter() {
return new MeterFilter() {
#Override
public Meter.Id map(Meter.Id id) {
if (id.getName().contains("name")) {
return id.withTag(Tag.of("key3", "value3"));
}
return id;
}
};
}