pyspark MQTT与Apache Bahir结构化流

Question

我正在使用spark 2.4，并且已经像这样运行pyspark：

./bin/pyspark --packages org.apache.bahir:spark-sql-streaming-mqtt_2.11:2.3.2

pyspark成功运行。 （但是当我运行spark-sql-streaming-mqtt_2.11：2.4.0-SNAPSHOT时，出现错误）

我正在尝试使用结构化流从MQTT代理获取数据。 所以，我已经运行了

>>> from pyspark.sql import SparkSession
>>> from pyspark.sql.functions import explode
>>> from pyspark.sql.functions import split
>>> spark = SparkSession \
...     .builder \
...     .appName("Test") \
...     .getOrCreate()
>>> lines = spark.readStream\
...     .format("org.apache.bahir.sql.streaming.mqtt.MQTTStreamSourceProvider")\
...     .option("topic", "/sensor")\
...     .option("brokerUrl", "tcp://localhost:1883")\
...     .load()

显示的错误：

2019-03-22 01:24:43 WARN  MQTTUtils:51 - If `clientId` is not set, a random value is picked up.
Recovering from failure is not supported in such a case.
Traceback (most recent call last):
  File "<stdin>", line 4, in <module>
  File "/opt/spark/python/pyspark/sql/streaming.py", line 400, in load
    return self._df(self._jreader.load())
  File "/opt/spark/python/lib/py4j-0.10.7-src.zip/py4j/java_gateway.py", line 1257, in __call__
  File "/opt/spark/python/pyspark/sql/utils.py", line 63, in deco
    return f(*a, **kw)
  File "/opt/spark/python/lib/py4j-0.10.7-src.zip/py4j/protocol.py", line 328, in get_return_value
py4j.protocol.Py4JJavaError: An error occurred while calling o43.load.
: MqttException (0)
    at org.eclipse.paho.client.mqttv3.persist.MqttDefaultFilePersistence.checkIsOpen(MqttDefaultFilePersistence.java:130)
    at org.eclipse.paho.client.mqttv3.persist.MqttDefaultFilePersistence.getFiles(MqttDefaultFilePersistence.java:247)
    at org.eclipse.paho.client.mqttv3.persist.MqttDefaultFilePersistence.close(MqttDefaultFilePersistence.java:142)
    at org.apache.bahir.sql.streaming.mqtt.MQTTStreamSource.stop(MQTTStreamSource.scala:228)
    at org.apache.spark.sql.streaming.DataStreamReader.load(DataStreamReader.scala:190)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at py4j.reflection.MethodInvoker.invoke(MethodInvoker.java:244)
    at py4j.reflection.ReflectionEngine.invoke(ReflectionEngine.java:357)
    at py4j.Gateway.invoke(Gateway.java:282)
    at py4j.commands.AbstractCommand.invokeMethod(AbstractCommand.java:132)
    at py4j.commands.CallCommand.execute(CallCommand.java:79)
    at py4j.GatewayConnection.run(GatewayConnection.java:238)
    at java.lang.Thread.run(Thread.java:748)

我尝试流式传输MQTT数据一周。 但是我不认为有办法解决它，而且确实很拼命。 我没有办法解决吗？ 谢谢。

Answer 1

尝试设置persistence选项。

范例：

   val lines = spark.readStream.format("datasource.mqtt.MQTTStreamSourceProvider")
  .option("topic", topic)
  .option("persistence","memory")
  .option("brokerUrl",broker)
  .option("cleanSession", "true")
  .load()