Spring Cloud Stream Kafka Streams函数式配置异常求助

问题现象 #

• IDEA对application.yml中的cloud.stream.function.definition提示未定义
• 应用启动时抛出错误：Invalid topology: Topology has no stream threads and no global threads, must subscribe to at least one source topic or global table

当前配置内容 #

Java配置类 #

@Configuration
@EnableKafka
@EnableKafkaStreams
public class Config {
...

@Bean
Consumer<KStream<String, String>> streamConsumer() {
... }

application.yml配置 #

spring: 
  cloud.stream.function.definition: streamConsumer
  cloud.stream.bindings.streamConsumer-in-0.destination: input-topic
  cloud.stream.bindings.streamConsumer-out-0.destination: output-topic
  cloud.stream.bindings.streamConsumer.group: stream-consumer-group

补充说明 #

怀疑是缺少依赖导致，但无法确认；添加以下组件后应用可正常启动：

@Component
public class WordProcessor {

@Autowired
void buildPipeline(StreamsBuilder streamsBuilder) { ... }

内容的提问来源于stack exchange，提问作者acme-j