pyspark MQTT structured streaming with apache bahir - apache-spark

Question

I'm using spark 2.4 and I've run pyspark like this:
./bin/pyspark --packages org.apache.bahir:spark-sql-streaming-mqtt_2.11:2.3.2
pyspark runs successfully.
(But when I run spark-sql-streaming-mqtt_2.11:2.4.0-SNAPSHOT, got an error)
I'm trying to get data from a MQTT broker using structured streaming.
so, I've run this
>>> 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()
the error shown:
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)
I tried to stream MQTT data for a week. But I don't think there is a way to solve it and it is really desperate. Is there no way I can solve it?
Thank you.

Answer 1

Try to set the persistence option.
Example :
val lines = spark.readStream.format("datasource.mqtt.MQTTStreamSourceProvider")
.option("topic", topic)
.option("persistence","memory")
.option("brokerUrl",broker)
.option("cleanSession", "true")
.load()