java.lang.IllegalStateException:这不应该发生,因为 headers() 应该只在处理记录时调用 [英] java.lang.IllegalStateException: This should not happen as headers() should only be called while a record is processed
问题描述
启动 Stream 应用程序(使用 Kafka Streams)失败并显示java.lang.IllegalStateException:这不应该发生,因为 headers() 应该只在处理记录时调用"
Starting up a Stream application (using Kafka Streams) fails with the "java.lang.IllegalStateException: This should not happen as headers() should only be called while a record is processed"
如果主题中已有数据,这似乎只会在我启动应用程序时发生.如果主题为空并且我开始向其推送数据,则一切正常.
This seems to only happen when I start up the application if there is already data in the topic. If the topic is empty and I start pushing data to it, all is fine.
有人知道为什么会这样吗?
Would someone know why this would happen?
谢谢
This should not happen as headers() should only be called while a record is processed
java.lang.IllegalStateException: This should not happen as headers() should only be called while a record is processed
at org.apache.kafka.streams.processor.internals.AbstractProcessorContext.headers(AbstractProcessorContext.java:149)
at org.apache.kafka.streams.state.internals.CachingKeyValueStore.putInternal(CachingKeyValueStore.java:235)
at org.apache.kafka.streams.state.internals.CachingKeyValueStore.put(CachingKeyValueStore.java:222)
at org.apache.kafka.streams.state.internals.CachingKeyValueStore.put(CachingKeyValueStore.java:37)
at org.apache.kafka.streams.state.internals.MeteredKeyValueStore.put(MeteredKeyValueStore.java:153)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl$KeyValueStoreReadWriteDecorator.put(ProcessorContextImpl.java:446)
at fr.mediametrie.GeoIPEnrichmentProcessor.transform(GeoIPEnrichmentProcessor.java:97)
at fr.mediametrie.GeoIPEnrichmentProcessor.transform(GeoIPEnrichmentProcessor.java:1)
at org.apache.kafka.streams.kstream.internals.TransformerSupplierAdapter$1.transform(TransformerSupplierAdapter.java:47)
at org.apache.kafka.streams.kstream.internals.TransformerSupplierAdapter$1.transform(TransformerSupplierAdapter.java:36)
at org.apache.kafka.streams.kstream.internals.KStreamFlatTransform$KStreamFlatTransformProcessor.process(KStreamFlatTransform.java:56)
at org.apache.kafka.streams.processor.internals.ProcessorNode.process(ProcessorNode.java:117)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:183)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:162)
at org.apache.kafka.streams.processor.internals.ProcessorContextImpl.forward(ProcessorContextImpl.java:122)
at org.apache.kafka.streams.processor.internals.SourceNode.process(SourceNode.java:87)
at org.apache.kafka.streams.processor.internals.StreamTask.process(StreamTask.java:364)
at org.apache.kafka.streams.processor.internals.AssignedStreamsTasks.process(AssignedStreamsTasks.java:199)
at org.apache.kafka.streams.processor.internals.TaskManager.process(TaskManager.java:420)
at org.apache.kafka.streams.processor.internals.StreamThread.runOnce(StreamThread.java:890)
at org.apache.kafka.streams.processor.internals.StreamThread.runLoop(StreamThread.java:805)
at org.apache.kafka.streams.processor.internals.StreamThread.run(StreamThread.java:774)
推荐答案
基于 Matthias 共享的信息,这里有一个实际示例:
Building on the information Matthias shared, here's a practical example:
- 返回相同的转换器对象(也适用于 Processor 和 ValueTransformer)会导致
IllegalStateException
:
var transformer = new Transformer();
inputStream
.transformValues(() -> transformer)
// further operations...
- 每次返回一个新实例可以防止异常:
inputStream
.transformValues(() -> new Transformer())
// further operations...
ps:我知道文档很清楚,但希望这可以节省一些滚动时间.
p.s: I am aware that the documentation is quite clear, but hope this saves some scrolling.
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