Missing bean 'zipkin2.reporter.Sender' when using `@AutoConfigureAfter(TraceAutoConfiguration.class)`

Question

TLDR :

• Repro project here : https://github.com/snussbaumer/zipkin-app-wont-start-repo
• I want to use a Zipkin Kafka Sender
• I also need a piece of AutoConfiguration to run after TraceAutoConfiguration from Sleuth
• If I use @AutoConfigureAfter the application does not start and fails with message No qualifying bean of type 'zipkin2.reporter.Sender' available

---

More details :

I'm trying to create a custom Sleuth instrumenting service that can also work when no tracing is available. Here is a really simplified version of the service interface :

public interface SomeService {
    String decorate(String value);
}

I then create an AutoConfiguration (as this code is in a separate module, used by many projects) :

@Configuration
@AutoConfigureAfter(name = "org.springframework.cloud.sleuth.autoconfig.TraceAutoConfiguration")
@Slf4j
public class TestAutoConfiguration {

    @ConditionalOnBean(type = "brave.Tracer")
    @Configuration
    public static class TracedConfiguration {

        @Bean
        public SomeService someService(Tracer tracer) {
            log.info("Create traced SomeService");
            return value -> value + " [" + tracer.currentSpan().toString() + "]";
        }
    }

    @ConditionalOnMissingBean(type = "brave.Tracer")
    @Configuration
    public static class NoTracedConfiguration {

        @Bean
        public SomeService someService() {
            log.info("Create not traced SomeService");
            return value -> value + " [not-traced]";
        }
    }
}

The idea is really to have a kind of Noop version of the service when no Tracer is available.

I then declare the the AutoConfiguration in a spring.factories file as usual.

This is the application I want to run :

@SpringBootApplication
@RestController
@Slf4j
public class ReproApplication {

    @Autowired
    private SomeService someService;

    @GetMapping("/test")
    public String test() {
        log.info("Test Endpoint called, check TraceId/SpanId/ParentSpanId in log");
        return someService.decorate("hello world") + "\n";
    }

    public static void main(String[] args) {
        SpringApplication.run(ReproApplication.class, args);
    }

}

For all of this I want to use Zipkin, with a KafkaSpanReporter. So my application.properties look like this :

spring.application.name=repro
server.port=8080
spring.kafka.bootstrapServers=kafka:9092
spring.sleuth.sampler.probability=1.0
spring.zipkin.sender.type=kafka
logging.level.org.springframework.boot.autoconfigure=DEBUG

and my (truncated) pom.xml like this :

<dependencies>
  <dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter</artifactId>
  </dependency>
  <dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
  </dependency>
  <dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-stream</artifactId>
  </dependency>
  <dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-stream-kafka</artifactId>
  </dependency>
  <dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-zipkin</artifactId>
  </dependency>
  <dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <version>1.16.20</version>
  </dependency>
</dependencies>

When I try to run this code I get an error :

No qualifying bean of type 'zipkin2.reporter.Sender' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {}

If I look at the configuration report I see :

Parameter 2 of method reporter in org.springframework.cloud.sleuth.zipkin2.ZipkinAutoConfiguration required a bean of type 'zipkin2.reporter.Sender' that could not be found.
    - Bean method 'kafkaSender' not loaded because @ConditionalOnBean (types: org.springframework.boot.autoconfigure.kafka.KafkaProperties; SearchStrategy: all) did not find any beans of type org.springframework.boot.autoconfigure.kafka.KafkaProperties

This is weird, because there is a @EnableConfigurationProperties(KafkaProperties.class) on KafkaAutoConfiguration and the configuration report clearly shows :

KafkaAutoConfiguration matched:
  - @ConditionalOnClass found required class 'org.springframework.kafka.core.KafkaTemplate'; @ConditionalOnMissingClass did not find unwanted class (OnClassCondition)

What is even weirder is that if I remove the @AutoConfigureAfter(name = "org.springframework.cloud.sleuth.autoconfig.TraceAutoConfiguration") in my AutoConfiguration, the service starts all right => but I get the NoTracedConfiguration flavour of my bean, so Tracer is probably not configured yet.

What can I do to fix this problem ?

Answer 1

Finally got it to work removing @AutoConfigureAfter, @ConditionalOnBean and @ConditionalOnMissingBean, using instead @ConditionalOnClass, @ConditionalOnMissingClass and reproducing other @Conditionals from TraceAutoConfiguration. Not great, but at least working.