spark-instrumented-optimizer/python/pyspark/streaming/mqtt.py
Josh Rosen 07cb323e7a [SPARK-13848][SPARK-5185] Update to Py4J 0.9.2 in order to fix classloading issue
This patch upgrades Py4J from 0.9.1 to 0.9.2 in order to include a patch which modifies Py4J to use the current thread's ContextClassLoader when performing reflection / class loading. This is necessary in order to fix [SPARK-5185](https://issues.apache.org/jira/browse/SPARK-5185), a longstanding issue affecting the use of `--jars` and `--packages` in PySpark.

In order to demonstrate that the fix works, I removed the workarounds which were added as part of [SPARK-6027](https://issues.apache.org/jira/browse/SPARK-6027) / #4779 and other patches.

Py4J diff: https://github.com/bartdag/py4j/compare/0.9.1...0.9.2

/cc zsxwing tdas davies brkyvz

Author: Josh Rosen <joshrosen@databricks.com>

Closes #11687 from JoshRosen/py4j-0.9.2.
2016-03-14 12:22:02 -07:00

71 lines
2.7 KiB
Python

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from py4j.protocol import Py4JJavaError
from pyspark.storagelevel import StorageLevel
from pyspark.serializers import UTF8Deserializer
from pyspark.streaming import DStream
__all__ = ['MQTTUtils']
class MQTTUtils(object):
@staticmethod
def createStream(ssc, brokerUrl, topic,
storageLevel=StorageLevel.MEMORY_AND_DISK_2):
"""
Create an input stream that pulls messages from a Mqtt Broker.
:param ssc: StreamingContext object
:param brokerUrl: Url of remote mqtt publisher
:param topic: topic name to subscribe to
:param storageLevel: RDD storage level.
:return: A DStream object
"""
try:
helper = ssc._jvm.org.apache.spark.streaming.mqtt.MQTTUtilsPythonHelper()
except TypeError as e:
if str(e) == "'JavaPackage' object is not callable":
MQTTUtils._printErrorMsg(ssc.sparkContext)
raise
jlevel = ssc._sc._getJavaStorageLevel(storageLevel)
jstream = helper.createStream(ssc._jssc, brokerUrl, topic, jlevel)
return DStream(jstream, ssc, UTF8Deserializer())
@staticmethod
def _printErrorMsg(sc):
print("""
________________________________________________________________________________________________
Spark Streaming's MQTT libraries not found in class path. Try one of the following.
1. Include the MQTT library and its dependencies with in the
spark-submit command as
$ bin/spark-submit --packages org.apache.spark:spark-streaming-mqtt:%s ...
2. Download the JAR of the artifact from Maven Central http://search.maven.org/,
Group Id = org.apache.spark, Artifact Id = spark-streaming-mqtt-assembly, Version = %s.
Then, include the jar in the spark-submit command as
$ bin/spark-submit --jars <spark-streaming-mqtt-assembly.jar> ...
________________________________________________________________________________________________
""" % (sc.version, sc.version))