Using RedisTemplate in a MeterBinder causes a circular dependency

[Kurok1]

Spring Boot Version

2.6.0+

How to Reproduce

Implments MeterBinder and inject RedisTemplate

@Service
public class InMemoryUserRegistrationService implements UserRegistrationService, MeterBinder {


    @Autowired
    private RedisTemplate redisTemplate;
    
    @Override
    public void bindTo(MeterRegistry registry) {

    }
}

Then I just launch the application, and Circular-References are created

Errors Output

***************************
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]
↑     ↓
|  userRegistrationService (field private org.springframework.data.redis.core.RedisTemplate com.xxx.biz.web.service.InMemoryUserRegistrationService.redisTemplate)
↑     ↓
|  redisTemplate defined in class path resource [org/springframework/boot/autoconfigure/data/redis/RedisAutoConfiguration.class]
↑     ↓
|  redisConnectionFactory defined in class path resource [org/springframework/boot/autoconfigure/data/redis/LettuceConnectionConfiguration.class]
↑     ↓
|  lettuceClientResources defined in class path resource [org/springframework/boot/autoconfigure/data/redis/LettuceConnectionConfiguration.class]
↑     ↓
|  lettuceMetrics defined in class path resource [org/springframework/boot/actuate/autoconfigure/metrics/redis/LettuceMetricsAutoConfiguration.class]
└─────┘


Action:

Relying upon circular references is discouraged and they are prohibited by default. Update your application to remove the dependency cycle between beans. As a last resort, it may be possible to break the cycle automatically by setting spring.main.allow-circular-references to true.

I ended up having RedisTemplate injected into my business code using @Lazy

[mhalbritter]

Your issue is titled RestTemplate but your code uses RedisTemplate. I assume you mean RedisTemplate in the title too?

[Kurok1]

I've changed the title

[mhalbritter]

I can't reproduce this. If you'd like us to spend some time investigating, please take the time to provide a complete minimal sample (something that we can unzip or git clone, build, and deploy) that reproduces the problem.

[Kurok1]

I have create a complete minimal sample) on GitHub. You can direct run DemoApplication and error will be occurred.

[mhalbritter]

Your example uses Spring Boot 2.6.9, which is no longer supported.

But this problem still persists in 2.7.6. It's working with Spring Boot 3.0.0

[Kurok1]

thanks

[philwebb]

I suspect #30636 is the reason this works in 3.0 but I'm not sure we can backport that fix to 2.x

[Kurok1]

Well, I have noticed that in version 3.0 MeterRegistryPostProcessor implementation of change.
But I think most people will not upgrade to the new version quickly, so we have to use ObjectProvider or @Lazy to solve this kind of problem

[ClaudenirFreitas]

Approach to fix this incident:

# application.properties file
spring.main.allow-circular-references=true

See Spring Boot 2.6 Release Notes - Circular References Prohibited by Default.

[philwebb]

I'm going to mark this one as a duplicate of #30636 but unfortunately we don't think we can safely backport the fix for that. Users on Spring Boot 2.x should use the workaround documented above.