Micronaut Micrometer Prometheus common tag configuration is not applying to all metrics

Question

Spring Boot allows the declarative configuration of common tags:

Commons tags are applied to all meters and can be configured, as the following example shows:

management.metrics.tags.region=us-east-1

Thus, in Spring Boot, with management.metrics.tags.application=myapp in place, all metrics include that tag, e.g.:

jvm_memory_max_bytes{application="myapp",area="heap",id="G1 Survivor Space"} -1.0
system_cpu_count{application="myapp"} 16.0

I want to achieve the same in a Micronaut application. There doesn't seem to be a declarative way to do it and instead, we need to programatically customize it using a MeterRegistryConfigurer.

I created the following:

@Singleton
@RequiresMetrics
class PrometheusMeterRegistryConfigurer: MeterRegistryConfigurer<MeterRegistry> {

    override fun configure(meterRegistry: MeterRegistry) {
        meterRegistry.config().commonTags("application", "myapp")
    }

    override fun getType(): Class<MeterRegistry> {
        return MeterRegistry::class.java
    }
}

The problem is it isn't applying it to all metrics, some metrics are tagged (http_server_requests_seconds_max) while other aren't (jvm_memory_max_bytes, system_cpu_count, etc.):

http_server_requests_seconds_max{application="myapp",exception="none",method="GET",status="200",uri="/actuator/prometheus",} 0.131942121
jvm_memory_max_bytes{area="nonheap",id="CodeHeap 'profiled nmethods'",} 1.22023936E8
system_cpu_count 16.0

How can I make the tag apply to all micrometer-prometheus metrics?

Answer 1

Solved adding two different MeterRegistryConfigurers:

@Singleton
@RequiresMetrics
class PrometheusMeterRegistryConfigurer: MeterRegistryConfigurer<PrometheusMeterRegistry> {

    override fun configure(meterRegistry: PrometheusMeterRegistry) {
        meterRegistry.config().commonTags("application", "myapp")
    }

    override fun getType(): Class<PrometheusMeterRegistry> {
        return PrometheusMeterRegistry::class.java
    }

}

@Singleton
@RequiresMetrics
class CompositeMeterRegistryConfigurer: MeterRegistryConfigurer<CompositeMeterRegistry> {

    override fun configure(meterRegistry: CompositeMeterRegistry) {
        meterRegistry.config().commonTags("application", "myapp")
    }

    override fun getType(): Class<CompositeMeterRegistry> {
        return CompositeMeterRegistry::class.java
    }
}