Micrometer Metrics

<dependency>
    <groupId>io.quarkus</groupId>
    <artifactId>quarkus-micrometer</artifactId>
</dependency>
<dependency>
    <groupId>com.acme</groupId>
    <artifactId>custom-micrometer-registry</artifactId>
    <version>...</version>
</dependency>

implementation("io.quarkus:quarkus-micrometer")
implementation("com.acme:custom-micrometer-registry")

@Produces
@Singleton (1)
public StatsdMeterRegistry createStatsdMeterRegistry(StatsdConfig statsdConfig, Clock clock) { (2)
    // define what to do with lines
    Consumer<String> lineLogger = line -> logger.info(line);

    // inject a configuration object, and then customize the line builder
    return StatsdMeterRegistry.builder(statsdConfig)
          .clock(clock)
          .lineSink(lineLogger)
          .build();
}

package org.acme.micrometer;

import io.micrometer.core.instrument.MeterRegistry;

import jakarta.ws.rs.GET;
import jakarta.ws.rs.Path;
import jakarta.ws.rs.Produces;

@Path("/example")
@Produces("text/plain")
public class ExampleResource {

    private final MeterRegistry registry;

    ExampleResource(MeterRegistry registry) {
        this.registry = registry;
    }
}

    @Inject
    MeterRegistry registry;

    MeterRegistry registry = Metrics.globalRegistry;

List<String> list = registry.gaugeCollectionSize("fantastic.list", (1)
        Tags.of("key", "value") // optional 2
        new ArrayList<>());  (3)

Gauge.builder("jvm.threads.peak", threadBean, ThreadMXBean::getPeakThreadCount) (1)
    .baseUnit(BaseUnits.THREADS) // optional 2
    .description("The peak live thread count...") // optional 3
    .tags("key", "value") // optional 4
    .register(registry); (5)

registry.counter("example.prime.number", "type", "prime"); // <1> 2

Counter.builder("count.me") (1)
    .baseUnit("beans")            // optional 2
    .description("a description") // optional 3
    .tags("region", "test")       // optional 4
    .register(registry);

@Counted(value = "counted.method", extraTags = { "extra", "annotated" }) // <1> 2
void countThisMethod(){
    ...
}

@Singleton
public class CustomConfiguration {

    @ConfigProperty(name = "deployment.env")
    String deploymentEnv;

    /** Define common tags that apply only to a Prometheus Registry */
    @Produces
    @Singleton
    @MeterFilterConstraint(applyTo = PrometheusMeterRegistry.class)
    public MeterFilter configurePrometheusRegistries() {
        return MeterFilter.commonTags(Arrays.asList(
                Tag.of("registry", "prometheus")));
    }

    /** Define common tags that apply globally */
    @Produces
    @Singleton
    public MeterFilter configureAllRegistries() {
        return MeterFilter.commonTags(Arrays.asList(
                Tag.of("env", deploymentEnv)));
    }

    /** Enable histogram buckets for a specific timer */
    @Produces
    @Singleton
    public MeterFilter enableHistogram() {
        return new MeterFilter() {
            @Override
            public DistributionStatisticConfig configure(Meter.Id id, DistributionStatisticConfig config) {
                if(id.getName().startsWith("myservice")) {
                    return DistributionStatisticConfig.builder()
                        .percentiles(0.5, 0.95)     // median and 95th percentile, not aggregable
                        .percentilesHistogram(true) // histogram buckets (e.g. prometheus histogram_quantile)
                        .build()
                        .merge(config);
                }
                return config;
            }
        };
    }
}