[FIXED] Upgrading to springboot 2.6.7 leads to cyclic dependency

Issue

I am upgrading my prooject from springboot 2.4.4 to 2.6.7 but in the newer version I am getting this runtime error due to cyclic dependency:

***************************
APPLICATION FAILED TO START
***************************

Description:

The dependencies of some of the beans in the application context form a cycle:

   webMvcMetricsFilter defined in class path resource [org/springframework/boot/actuate/autoconfigure/metrics/web/servlet/WebMvcMetricsAutoConfiguration.class]
┌─────┐
|  prometheusMeterRegistry defined in class path resource [org/springframework/boot/actuate/autoconfigure/metrics/export/prometheus/PrometheusMetricsExportAutoConfiguration.class]
↑     ↓
|  meterRegistryConfig defined in URL [jar:file:/Users/myname/Documents/repo/myrepo/my-module/bin/my-module.jar!/com/mypackage/app/metrics/MeterRegistryConfig.class]
└─────┘

This is my MeterRegistryConfig class:

import io.micrometer.core.instrument.Meter;
import io.micrometer.core.instrument.MeterRegistry;
import io.micrometer.core.instrument.config.MeterFilter;
import io.micrometer.core.instrument.distribution.DistributionStatisticConfig;
import org.jetbrains.annotations.NotNull;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

@Component
public class MeterRegistryConfig implements MeterFilter {

  @Autowired
  public MeterRegistryConfig(final MeterRegistry registry) {
    registry
        .config()
        .meterFilter(
            new MeterFilter() {
              @Override
              public DistributionStatisticConfig configure(
                  @NotNull final Meter.Id id, @NotNull final DistributionStatisticConfig config) {
                return DistributionStatisticConfig.builder()
                    .percentilesHistogram(true)
                    .percentilePrecision(3)
                    .build()
                    .merge(config);
              }
            });
  }
}

I am not sure why this cyclic dependency is happening with the newer version and not the older one. Can anyone please help me resolving it?

Solution

Spring Boot will automatically add every MeterFilter bean to the auto-configured MeterRegistry so your MeterRegistryConfig in its current form isn't needed. I'd replace it with a @Configuration class that defines a MeterFilter bean. Something like this:

import io.micrometer.core.instrument.Meter;
import io.micrometer.core.instrument.config.MeterFilter;
import io.micrometer.core.instrument.distribution.DistributionStatisticConfig;
import org.jetbrains.annotations.NotNull;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
class MeterRegistryConfig {

    @Bean
    MeterFilter yourMeterFilter() {
        return new MeterFilter() {
            @Override
            public DistributionStatisticConfig configure(
                    @NotNull final Meter.Id id,
                    @NotNull final DistributionStatisticConfig config) {
                return DistributionStatisticConfig.builder()
                    .percentilesHistogram(true)
                    .percentilePrecision(3)
                    .build()
                    .merge(config);
            }
        };
    }

}

Answered By - Andy Wilkinson
Answer Checked By - Dawn Plyler (JavaFixing Volunteer)