Python ReadFromKafka抛出值错误：不支持的信号：2

目前，我试图与ApacheKafka一起掌握ApacheBeam的诀窍

Kafka服务正在（本地）运行，我使用Kafka控制台生成器编写了一些测试消息

首先，我编写了这个Java代码片段，用我熟悉的语言测试ApacheBeam。它的工作原理与预期一致

public class Main {

  public static void main(String[] args) {

    Pipeline pipeline = Pipeline.create();

    Read<Long, String> kafkaReader = KafkaIO.<Long, String>read()
        .withBootstrapServers("localhost:9092")
        .withTopic("beam-test")
        .withKeyDeserializer(LongDeserializer.class)
        .withValueDeserializer(StringDeserializer.class);

    kafkaReader.withoutMetadata();

    pipeline
        .apply("Kafka", kafkaReader
        ).apply(
          "Extract words", ParDo.of(new DoFn<KafkaRecord<Long, String>, String>() {
            @ProcessElement
          public void processElement(ProcessContext c){
              System.out.println("Key:" + c.element().getKV().getKey() + " | Value: " + c.element().getKV().getValue());
            }
        })
    );

    pipeline.run();
  }
}

现在来谈谈问题。当我尝试运行python代码时，出现以下错误：

(app) λ python ArghKafkaExample.py 
Traceback (most recent call last):
  File "ArghKafkaExample.py", line 22, in <module>
    run_pipe()
  File "ArghKafkaExample.py", line 10, in run_pipe
    (p
  File "C:\Users\gamef\git\BeamMeScotty\app\lib\site-packages\apache_beam\transforms\ptransform.py", line 1028, in __ror__
    return self.transform.__ror__(pvalueish, self.label)
  File "C:\Users\gamef\git\BeamMeScotty\app\lib\site-packages\apache_beam\transforms\ptransform.py", line 572, in __ror__
    result = p.apply(self, pvalueish, label)
  File "C:\Users\gamef\git\BeamMeScotty\app\lib\site-packages\apache_beam\pipeline.py", line 648, in apply
    return self.apply(transform, pvalueish)
  File "C:\Users\gamef\git\BeamMeScotty\app\lib\site-packages\apache_beam\pipeline.py", line 691, in apply
    pvalueish_result = self.runner.apply(transform, pvalueish, self._options)
  File "C:\Users\gamef\git\BeamMeScotty\app\lib\site-packages\apache_beam\runners\runner.py", line 198, in apply
    return m(transform, input, options)
  File "C:\Users\gamef\git\BeamMeScotty\app\lib\site-packages\apache_beam\runners\runner.py", line 228, in apply_PTransform
    return transform.expand(input)
  File "C:\Users\gamef\git\BeamMeScotty\app\lib\site-packages\apache_beam\transforms\external.py", line 322, in expand
    self._expanded_components = self._resolve_artifacts(
  File "C:\Users\gamef\AppData\Local\Programs\Python\Python38\lib\contextlib.py", line 120, in __exit__
    next(self.gen)
  File "C:\Users\gamef\git\BeamMeScotty\app\lib\site-packages\apache_beam\transforms\external.py", line 372, in _service
    yield stub
  File "C:\Users\gamef\git\BeamMeScotty\app\lib\site-packages\apache_beam\transforms\external.py", line 523, in __exit__
    self._service_provider.__exit__(*args)
  File "C:\Users\gamef\git\BeamMeScotty\app\lib\site-packages\apache_beam\utils\subprocess_server.py", line 74, in __exit__
    self.stop()
  File "C:\Users\gamef\git\BeamMeScotty\app\lib\site-packages\apache_beam\utils\subprocess_server.py", line 133, in stop
    self.stop_process()
  File "C:\Users\gamef\git\BeamMeScotty\app\lib\site-packages\apache_beam\utils\subprocess_server.py", line 179, in stop_process
    return super(JavaJarServer, self).stop_process()
  File "C:\Users\gamef\git\BeamMeScotty\app\lib\site-packages\apache_beam\utils\subprocess_server.py", line 143, in stop_process
    self._process.send_signal(signal.SIGINT)
  File "C:\Users\gamef\AppData\Local\Programs\Python\Python38\lib\subprocess.py", line 1434, in send_signal
    raise ValueError("Unsupported signal: {}".format(sig))
ValueError: Unsupported signal: 2

（app）λpython ArghKafkaExample.py
回溯（最近一次呼叫最后一次）：
文件“arghkafakaexample.py”，第22行，在
管道
管路中第10行的文件“ArghKafkaExample.py”
（p
文件“C:\Users\gamef\git\beamescotty\app\lib\site packages\apache\u beam\transforms\pttransform.py”，第1028行，错误__
返回self.transform.\uuuuror\uuuuuuu（pValue，self.label）
文件“C:\Users\gamef\git\beamescotty\app\lib\site packages\apache\u beam\transforms\pttransform.py”，第572行，错误__
结果=p.apply（self、pvaluelish、label）
文件“C:\Users\gamef\git\beamescotty\app\lib\site packages\apache\u beam\pipeline.py”，第648行，在apply中
返回self.apply（transform，pvalueish）
文件“C:\Users\gamef\git\beamescotty\app\lib\site packages\apache\u beam\pipeline.py”，第691行，在apply中
pvalueish_结果=self.runner.apply（转换、pvalueish、self._选项）
文件“C:\Users\gamef\git\beamescotty\app\lib\site packages\apache\u beam\runners\runner.py”，第198行，在apply中
返回m（变换、输入、选项）
文件“C:\Users\gamef\git\beamescotty\app\lib\site packages\apache\u beam\runners\runner.py”，第228行，在apply\u PTransform中
返回transform.expand（输入）
文件“C:\Users\gamef\git\beamescotty\app\lib\site packages\apache\u beam\transforms\external.py”，第322行，展开
self.\u扩展的\u组件=self.\u解析\u工件(
文件“C:\Users\gamef\AppData\Local\Programs\Python\Python38\lib\contextlib.py”，第120行，在退出时__
下一个（self.gen）
文件“C:\Users\gamef\git\beamescotty\app\lib\site packages\apache\u beam\transforms\external.py”，第372行，在\u服务中
产量存根
文件“C:\Users\gamef\git\beamescotty\app\lib\site packages\apache\u beam\transforms\external.py”，第523行，在\uuuu出口处__
自助服务提供商退出（*args）
文件“C:\Users\gamef\git\beamescotty\app\lib\site packages\apache\u beam\utils\subprocess\u server.py”，第74行，在退出中__
self.stop（）
文件“C:\Users\gamef\git\beamescotty\app\lib\site packages\apache\u beam\utils\subprocess\u server.py”，第133行，在stop中
self.stop_进程（）
文件“C:\Users\gamef\git\beamescotty\app\lib\site packages\apache\u beam\utils\subprocess\u server.py”，第179行，在stop\u进程中
返回super（JavaJarServer，self）.stop_进程（）
文件“C:\Users\gamef\git\beamescotty\app\lib\site packages\apache\u beam\utils\subprocess\u server.py”，第143行，在stop\u进程中
自处理发送信号（signal.SIGINT）
文件“C:\Users\gamef\AppData\Local\Programs\Python\Python38\lib\subprocess.py”，第1434行，在发送信号中
raise VALUERROR（“不支持的信号：{}”。格式（sig））
ValueError:不支持的信号：2

通过谷歌搜索我发现，这与程序退出代码（如Strg+C）有关，但总体而言，我完全不知道问题出在哪里

任何建议都会有帮助

---

您好Pascal

您的管道代码在这里似乎是正确的。此问题是由于Python SDK中Kafka IO的要求造成的。来自：

这些转换目前由Beam便携式runner（例如，便携式Flink和Spark）以及Dataflow runner支持

本模块中提供的转换是在Beam Java SDK中实现的跨语言转换。在管道构建过程中，Python SDK将连接到Java扩展服务以扩展这些转换。为方便起见，在Beam Python管道中使用这些转换之前，需要进行少量设置

Kafka IO在Python中作为Java中的跨语言转换实现，而您的管道正在失败，因为您尚未设置执行跨语言转换的环境。用外行的话说，解释什么是跨语言转换：这意味着Kafka转换实际上是在Java SDK而不是Python SDK上执行的，因此它可以利用Java上现有的Kafka代码

有两个障碍阻止管道工作。更容易修复的障碍是，只有我上面引用的运行程序支持跨语言转换，因此，如果您使用直接运行程序运行管道，它将无法工作，您需要在本地模式下切换到Flink或Spark运行程序

更棘手的障碍是，您需要启动扩展服务才能将外部转换添加到管道中。由于Beam试图扩展转换，但无法连接到扩展服务，并且扩展失败，因此发生了stacktrace

---

尽管有额外的设置，如果您仍想尝试使用跨语言运行此功能，我链接的文档包含运行扩展服务的说明。在我编写此答案时，此功能仍然是新功能，文档中可能存在盲点。如果您遇到问题，我鼓励您在t上提问he.

嗨，Daniel，将默认扩展服务添加为……扩展服务="localhost:8097出现以下错误：grpc.\u channel.\u inactioverpcerror:如果没有任何其他上下文，这很可能是端口问题。请确保您尝试使用的所有端口都是打开的。但是如果您需要更详细的帮助，我建议创建一个关于该错误的新堆栈溢出问题，并提供更多上下文，或者询问邮件列表/sl正如我上面建议的那样，确认频道。嗨，丹尼尔，

(app) λ python ArghKafkaExample.py 
Traceback (most recent call last):
  File "ArghKafkaExample.py", line 22, in <module>
    run_pipe()
  File "ArghKafkaExample.py", line 10, in run_pipe
    (p
  File "C:\Users\gamef\git\BeamMeScotty\app\lib\site-packages\apache_beam\transforms\ptransform.py", line 1028, in __ror__
    return self.transform.__ror__(pvalueish, self.label)
  File "C:\Users\gamef\git\BeamMeScotty\app\lib\site-packages\apache_beam\transforms\ptransform.py", line 572, in __ror__
    result = p.apply(self, pvalueish, label)
  File "C:\Users\gamef\git\BeamMeScotty\app\lib\site-packages\apache_beam\pipeline.py", line 648, in apply
    return self.apply(transform, pvalueish)
  File "C:\Users\gamef\git\BeamMeScotty\app\lib\site-packages\apache_beam\pipeline.py", line 691, in apply
    pvalueish_result = self.runner.apply(transform, pvalueish, self._options)
  File "C:\Users\gamef\git\BeamMeScotty\app\lib\site-packages\apache_beam\runners\runner.py", line 198, in apply
    return m(transform, input, options)
  File "C:\Users\gamef\git\BeamMeScotty\app\lib\site-packages\apache_beam\runners\runner.py", line 228, in apply_PTransform
    return transform.expand(input)
  File "C:\Users\gamef\git\BeamMeScotty\app\lib\site-packages\apache_beam\transforms\external.py", line 322, in expand
    self._expanded_components = self._resolve_artifacts(
  File "C:\Users\gamef\AppData\Local\Programs\Python\Python38\lib\contextlib.py", line 120, in __exit__
    next(self.gen)
  File "C:\Users\gamef\git\BeamMeScotty\app\lib\site-packages\apache_beam\transforms\external.py", line 372, in _service
    yield stub
  File "C:\Users\gamef\git\BeamMeScotty\app\lib\site-packages\apache_beam\transforms\external.py", line 523, in __exit__
    self._service_provider.__exit__(*args)
  File "C:\Users\gamef\git\BeamMeScotty\app\lib\site-packages\apache_beam\utils\subprocess_server.py", line 74, in __exit__
    self.stop()
  File "C:\Users\gamef\git\BeamMeScotty\app\lib\site-packages\apache_beam\utils\subprocess_server.py", line 133, in stop
    self.stop_process()
  File "C:\Users\gamef\git\BeamMeScotty\app\lib\site-packages\apache_beam\utils\subprocess_server.py", line 179, in stop_process
    return super(JavaJarServer, self).stop_process()
  File "C:\Users\gamef\git\BeamMeScotty\app\lib\site-packages\apache_beam\utils\subprocess_server.py", line 143, in stop_process
    self._process.send_signal(signal.SIGINT)
  File "C:\Users\gamef\AppData\Local\Programs\Python\Python38\lib\subprocess.py", line 1434, in send_signal
    raise ValueError("Unsupported signal: {}".format(sig))
ValueError: Unsupported signal: 2