example percentiles - spring boot

AppConfig.java

package org.eclipse.jkube.maven.sample.spring.boot;

import io.prometheus.client.CollectorRegistry;
import io.prometheus.client.Histogram;
import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Lazy;

@Configuration
@ConditionalOnProperty(value = "custom-metric.enabled", havingValue = "true")
public class AppConfig {

    @Bean
    @Lazy
    public Histogram requestDurationHistogram(CollectorRegistry collectorRegistry) {
        return Histogram.build()
                .name("request_duration")
                .help("Latency for HTTP request.")
                .linearBuckets(0.1,0.1, 40)
                .labelNames()
                .register(collectorRegistry);
    }
}

CollectRequestDuration.java

package org.eclipse.jkube.maven.sample.spring.boot;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface CollectRequestDuration {
}

RecordRequestDurationMetric.java

package org.eclipse.jkube.maven.sample.spring.boot;

import io.prometheus.client.Histogram;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
import org.springframework.stereotype.Component;

@Aspect
@Component
@ConditionalOnBean(AppConfig.class)
public class RecordRequestDurationMetric {

    private Histogram requestDurationHistogram;

    public RecordRequestDurationMetric(Histogram requestDurationHistogram) {
        this.requestDurationHistogram = requestDurationHistogram;
    }

    @Around("@annotation(CollectRequestDuration)")
    public Object recordRequestDuration(ProceedingJoinPoint pjp) throws Throwable {

        Histogram.Timer timer = requestDurationHistogram.startTimer();
        Object result;
        try {
            result = pjp.proceed();
        } finally {
            timer.observeDuration();
        }
        return result;
    }

}