Upgrading to springboot 2.6.7 leads to cyclic dependency

Question

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?

Spring Boot 2.6 prohibits all circular references by default. All `MeterFilter` beans are needed when creating the `MeterRegistry` so injecting the `MeterRegistry` into `MeterRegistry` config when implements `MeterFilter` creates a cycle. Why is your `MeterRegistryConfig` a `MeterFilter`? — Andy Wilkinson, Apr 26 '22 at 11:24
Yeah most likely this issue was always there in my project but it never showed because older spring-boot versions ignored circular dependencies(don't know how can we force it to fail if they exists). I know we can ignore the circular dependency in newer versions by a property but I wanted to solve the issue at its root. My MeterRegistryConfig is not a MeterFilter. We are creating the anonymous inner object and setting it as meterFilter in the config and then creating its bean. How else can I add the meterFilter to the meter registry config? — rishav, Apr 26 '22 at 11:32
I am guessing I need to create a MeterRegistryCustomizer bean? But I am not sure if that is indeed the best way. — rishav, Apr 26 '22 at 11:46

score 3 · Accepted Answer · answered Apr 26 '22 at 11:46

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);
            }
        };
    }

}

Upgrading to springboot 2.6.7 leads to cyclic dependency

1 Answers1