spring-cloud-stream - 使用 'zipkin2.reporter.Sender' 时缺少 bean `@AutoConfigureAfter(TraceAutoConfiguration.class)`

Question

总而言之:

• 此处复制项目:https://github.com/snussbaumer/zipkin-app-wont-start-repo
• 我想使用 Zipkin Kafka Sender
• 我还需要一段 AutoConfiguration 在 Sleuth 的 TraceAutoConfiguration 之后运行
• 如果我使用 @AutoConfigureAfter，应用程序不会启动并失败并显示消息 No qualifying bean of type 'zipkin2.reporter.Sender' available

---

更多详情:

我正在尝试创建一个自定义 Sleuth 检测服务，该服务在没有可用跟踪时也能正常工作。这是服务接口(interface)的真正简化版本:

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

然后我创建一个自动配置(因为这段代码在一个单独的模块中，被许多项目使用):

@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]";
        }
    }
}

这个想法实际上是在没有 Tracer 可用时提供一种 Noop 版本的服务。

然后我像往常一样在 spring.factories 文件中声明 AutoConfiguration。

这是我要运行的应用程序:

@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);
    }

}

对于所有这些，我想使用 Zipkin 和 KafkaSpanReporter。所以我的 application.properties 看起来像这样:

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

和我的(截断的)pom.xml 是这样的:

<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>

当我尝试运行此代码时出现错误:

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

如果我查看配置报告，我会看到:

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

这很奇怪，因为 KafkaAutoConfiguration 上有一个 @EnableConfigurationProperties(KafkaProperties.class) 并且配置报告清楚地显示:

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

更奇怪的是，如果我在我的 AutoConfiguration 中删除 @AutoConfigureAfter(name = "org.springframework.cloud.sleuth.autoconfig.TraceAutoConfiguration")，服务将正常启动 =>但是我得到了我的 bean 的 NoTracedConfiguration 风格，所以 Tracer 可能还没有配置。

我该怎么做才能解决这个问题？

Answer 1

终于开始使用 @AutoConfigureAfter、@ConditionalOnBean 和 @ConditionalOnMissingBean，改用 @ConditionalOnClass , @ConditionalOnMissingClass 并从 TraceAutoConfiguration 复制其他 @Conditionals。不是很好，但至少可以工作。