Question

我的kafka主题中有流数据。我需要使用pyspark以pyspark数据帧的形式从主题中读取此数据。但是当我调用readStream函数时，我不断收到错误。错误是“py4j.protocol.Py4JJavaError：调用o35.load时发生错误”。我的代码如下： -

os.environ['PYSPARK_SUBMIT_ARGS'] = '--packages org.apache.spark:spark-streaming-kafka-0-8_2.11:2.0.2 pyspark-shell'

if __name__ == '__main__':
    sc = SparkSession.builder.appName('PythonStreamingDirectKafkaWordCount').getOrCreate()

    ssc = StreamingContext(sc, 60)

    df = sc \
        .readStream \
        .format("kafka") \
        .option("kafka.bootstrap.servers", "localhost:9092") \
        .option("subscribe", "near_line") \
        .load() \
        .selectExpr("CAST(key AS STRING)", "CAST(value AS STRING)","CAST(value AS STRING)")

    ssc.start()
    ssc.awaitTermination()

我收到如下错误： -

Traceback (most recent call last):
  File "/home/nayanam/PycharmProjects/recommendation_engine/derivation/kafka_cons**umer_test.py", line 21, in <module>
    .option("subscribe", "near_line") \**
  File "/home/nayanam/anaconda3/lib/python3.5/site-packages/pyspark/sql/streaming.py", line 397, in load
    return self._df(self._jreader.load())
  File "/home/nayanam/anaconda3/lib/python3.5/site-packages/py4j/java_gateway.py", line 1133, in __call__
    answer, self.gateway_client, self.target_id, self.name)
  File "/home/nayanam/anaconda3/lib/python3.5/site-packages/pyspark/sql/utils.py", line 63, in deco
    return f(*a, **kw)
  File "/home/nayanam/anaconda3/lib/python3.5/site-packages/py4j/protocol.py", line 319, in get_return_value
    format(target_id, ".", name), value)
py4j.protocol.Py4JJavaError: An error occurred while calling o35.load.
: java.lang.ClassNotFoundException: Failed to find data source: kafka. Please find packages at http://spark.apache.org/third-party-projects.html
    at org.apache.spark.sql.execution.datasources.DataSource$.lookupDataSource(DataSource.scala:549)
    at org.apache.spark.sql.execution.datasources.DataSource.providingClass$lzycompute(DataSource.scala:86)
    at org.apache.spark.sql.execution.datasources.DataSource.providingClass(DataSource.scala:86)
    at org.apache.spark.sql.execution.datasources.DataSource.sourceSchema(DataSource.scala:195)
    at org.apache.spark.sql.execution.datasources.DataSource.sourceInfo$lzycompute(DataSource.scala:87)
    at org.apache.spark.sql.execution.datasources.DataSource.sourceInfo(DataSource.scala:87)
    at org.apache.spark.sql.execution.streaming.StreamingRelation$.apply(StreamingRelation.scala:30)
    at org.apache.spark.sql.streaming.DataStreamReader.load(DataStreamReader.scala:150)
    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:280)
    at py4j.commands.AbstractCommand.invokeMethod(AbstractCommand.java:132)
    at py4j.commands.CallCommand.execute(CallCommand.java:79)
    at py4j.GatewayConnection.run(GatewayConnection.java:214)
    at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.ClassNotFoundException: kafka.DefaultSource
    at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    at org.apache.spark.sql.execution.datasources.DataSource$$anonfun$21$$anonfun$apply$12.apply(DataSource.scala:533)
    at org.apache.spark.sql.execution.datasources.DataSource$$anonfun$21$$anonfun$apply$12.apply(DataSource.scala:533)
    at scala.util.Try$.apply(Try.scala:192)
    at org.apache.spark.sql.execution.datasources.DataSource$$anonfun$21.apply(DataSource.scala:533)
    at org.apache.spark.sql.execution.datasources.DataSource$$anonfun$21.apply(DataSource.scala:533)
    at scala.util.Try.orElse(Try.scala:84)
    at org.apache.spark.sql.execution.datasources.DataSource$.lookupDataSource(DataSource.scala:533)
    ... 18 more

Answer 1

如果您不想使用jar，请通过此软件包 --packages org.apache.spark：spark-sql-kafka-0-10_2.11：2.3.2，org.apache.spark：spark-streaming-kafka-0-10-assembly_2.11：2.3.2

Answer 2

我遇到了同样的问题。好吧，在spark 2.3中，pyspark接受--jars选项，并且可以正常工作。因此，在此版本中，您只需要2个jar：

我正在使用可从apache.org下载的Spark 2.3.0，Scala 2.11.8和Kafka 0.10

无法使用pyspark从kafka读取数据

2 个答案: