结构化流错误py4j.protocol.Py4JNetworkError:来自Java端的答案为空 [英] Structured Streaming error py4j.protocol.Py4JNetworkError: Answer from Java side is empty

问题描述

我正在尝试使用PySpark和结构化流(Spark 2.3)在两个Kafka Stream之间建立左外部连接.

I'm trying to make a left outer join between two Kafka Stream using PySpark and Structured Streaming (Spark 2.3).

import os
import time

from pyspark.sql.types import *
from pyspark.sql.functions import from_json, col, struct, explode, get_json_object
from ast import literal_eval
from pyspark.sql import SparkSession
from pyspark.sql.functions import expr

os.environ['PYSPARK_SUBMIT_ARGS'] = '--packages org.apache.spark:spark-sql-kafka-0-10_2.11:2.3.0 pyspark-shell'

spark = SparkSession \
    .builder \
    .appName("Spark Kafka Structured Streaming") \
    .getOrCreate()

schema_impressions = StructType() \
    .add("id_req", StringType()) \
    .add("ts_imp_request", TimestampType()) \
    .add("country", StringType()) \
    .add("TS_IMPRESSION", TimestampType()) 

schema_requests = StructType() \
    .add("id_req", StringType()) \
    .add("page", StringType()) \
    .add("conntype", StringType()) \
    .add("TS_REQUEST", TimestampType()) 

impressions = spark.readStream \
  .format("kafka") \
  .option("kafka.bootstrap.servers", "ip-ec2.internal:9092") \
  .option("subscribe", "ssp.datascience_impressions") \
  .load()

requests = spark \
  .readStream \
  .format("kafka") \
  .option("kafka.bootstrap.servers", "ip-ec2.internal:9092") \
  .option("subscribe", "ssp.datascience_requests") \
  .option("startingOffsets", "latest") \
  .load()

query_requests = requests \
        .select(col("timestamp"), col("key").cast("string"), from_json(col("value").cast("string"), schema_requests).alias("parsed")) \
        .select(col("timestamp").alias("timestamp_req"), "parsed.id_req", "parsed.page", "parsed.conntype", "parsed.TS_REQUEST") \
        .withWatermark("timestamp_req", "120 seconds") 

query_impressions = impressions \
        .select(col("timestamp"), col("key").cast("string"), from_json(col("value").cast("string"), schema_impressions).alias("parsed")) \
        .select(col("timestamp").alias("timestamp_imp"), col("parsed.id_req").alias("id_imp"), "parsed.ts_imp_request", "parsed.country", "parsed.TS_IMPRESSION") \
        .withWatermark("timestamp_imp", "120 seconds") 

query_requests.printSchema()        
query_impressions.printSchema()

> root  
|-- timestamp_req: timestamp (nullable = true)  
|-- id_req: string (nullable = true)  
|-- page: string (nullable = true)  
|-- conntype: string (nullable = true)  
|-- TS_REQUEST: timestamp (nullable = true)
> 
> root  |-- timestamp_imp: timestamp (nullable = true)  
|-- id_imp: string (nullable = true)  
|-- ts_imp_request: timestamp (nullable = true)  
|-- country: string (nullable = true)  
|-- TS_IMPRESSION: timestamp (nullable = true)

在简历中，我将从两个Kafka流中获取数据，在接下来的几行中，我将尝试使用ID进行联接.

In resume, I will obtain data from two Kafka Streams, and in the next lines, I will try to make join using the IDs.

rawQuery = query_requests.join(query_impressions,  expr(""" 
    (id_req = id_imp AND 
    timestamp_imp >= timestamp_req AND 
    timestamp_imp <= timestamp_req + interval 5 minutes) 
    """), 
  "leftOuter")

rawQuery = rawQuery \
        .writeStream \
        .format("parquet") \
        .option("checkpointLocation", "/home/jovyan/streaming/applicationHistory") \
        .option("path", "/home/jovyan/streaming").start()
print(rawQuery.status)

{'message':'正在处理新数据'，'isDataAvailable':是，'isTriggerActive':True}发送命令时出现ERROR:root:Exception.追溯(最近一次通话):文件"/opt/conda/lib/python3.6/site-packages/py4j/java_gateway.py"，行1062，在send_command中引发Py4JNetworkError("Java端的答案为空")py4j.protocol.Py4JNetworkError:Java端的答案为空

{'message': 'Processing new data', 'isDataAvailable': True, 'isTriggerActive': True} ERROR:root:Exception while sending command. Traceback (most recent call last): File "/opt/conda/lib/python3.6/site-packages/py4j/java_gateway.py", line 1062, in send_command raise Py4JNetworkError("Answer from Java side is empty") py4j.protocol.Py4JNetworkError: Answer from Java side is empty

在处理上述异常期间，发生了另一个异常:

During handling of the above exception, another exception occurred:

回溯(最近通话最近):文件"/opt/conda/lib/python3.6/site-packages/py4j/java_gateway.py"，行908，在send_command中响应= connection.send_command(命令)文件"/opt/conda/lib/python3.6/site-packages/py4j/java_gateway.py"，行1067，在send_command中py4j.protocol.Py4JNetworkError:接收时出错"，proto.ERROR_ON_RECEIVE)错误:py4j.java_gateway:尝试连接到时发生错误Java服务器(127.0.0.1:33968)追溯(最近一次调用为:):
文件"/opt/conda/lib/python3.6/site-packages/IPython/core/interactiveshell.py"，第2910行，在run_code中exec(code_obj，self.user_global_ns，self.user_ns)文件"，第3行，在打印(rawQuery.status)文件"/opt/conda/lib/python3.6/site-packages/pyspark/sql/streaming.py"，第114行，状态为返回json.loads(self._jsq.status().json())文件"/opt/conda/lib/python3.6/site-packages/py4j/java_gateway.py"，行1160，在致电中答案，self.gateway_client，self.target_id，self.name)文件"/opt/conda/lib/python3.6/site-packages/pyspark/sql/utils.py"，行63，在装饰中返回f(* a，** kw)文件"/opt/conda/lib/python3.6/site-packages/py4j/protocol.py"，第328行，在get_return_value中格式(target_id，."，名称))py4j.protocol.Py4JError:调用o92.status时发生错误

Traceback (most recent call last): File "/opt/conda/lib/python3.6/site-packages/py4j/java_gateway.py", line 908, in send_command response = connection.send_command(command) File "/opt/conda/lib/python3.6/site-packages/py4j/java_gateway.py", line 1067, in send_command "Error while receiving", e, proto.ERROR_ON_RECEIVE) py4j.protocol.Py4JNetworkError: Error while receiving ERROR:py4j.java_gateway:An error occurred while trying to connect to the Java server (127.0.0.1:33968) Traceback (most recent call last):
File "/opt/conda/lib/python3.6/site-packages/IPython/core/interactiveshell.py", line 2910, in run_code exec(code_obj, self.user_global_ns, self.user_ns) File "", line 3, in print(rawQuery.status) File "/opt/conda/lib/python3.6/site-packages/pyspark/sql/streaming.py", line 114, in status return json.loads(self._jsq.status().json()) File "/opt/conda/lib/python3.6/site-packages/py4j/java_gateway.py", line 1160, in call answer, self.gateway_client, self.target_id, self.name) File "/opt/conda/lib/python3.6/site-packages/pyspark/sql/utils.py", line 63, in deco return f(*a, **kw) File "/opt/conda/lib/python3.6/site-packages/py4j/protocol.py", line 328, in get_return_value format(target_id, ".", name)) py4j.protocol.Py4JError: An error occurred while calling o92.status

在处理上述异常期间，发生了另一个异常:

During handling of the above exception, another exception occurred:

回溯(最近通话最近):文件"/opt/conda/lib/python3.6/site-packages/IPython/core/interactiveshell.py"，在showtraceback中的第1828行stb = value._render_traceback_()AttributeError:"Py4JError"对象没有属性"_render_traceback _"

Traceback (most recent call last): File "/opt/conda/lib/python3.6/site-packages/IPython/core/interactiveshell.py", line 1828, in showtraceback stb = value._render_traceback_() AttributeError: 'Py4JError' object has no attribute '_render_traceback_'

在处理上述异常期间，发生了另一个异常:

During handling of the above exception, another exception occurred:

回溯(最近通话最近):文件"/opt/conda/lib/python3.6/site-packages/py4j/java_gateway.py"，行852，在_get_connection中connection = self.deque.pop()IndexError:从一个空的双端队列弹出

Traceback (most recent call last): File "/opt/conda/lib/python3.6/site-packages/py4j/java_gateway.py", line 852, in _get_connection connection = self.deque.pop() IndexError: pop from an empty deque

我正在使用Jupyter Notebook在本地运行Spark.在spark/conf/ spark-defaults.conf 中，我有:

I'm running Spark in local using Jupyter Notebook. In the spark/conf/spark-defaults.conf I have:

# Example:
# spark.master                     spark://master:7077
# spark.eventLog.enabled           true
# spark.eventLog.dir               hdfs://namenode:8021/directory
# spark.serializer                 org.apache.spark.serializer.KryoSerializer
spark.driver.memory             15g
# spark.executor.extraJavaOptions  -XX:+PrintGCDetails -Dkey=value -Dnumbers="one two three"

如果在上一个错误之后尝试使用Spark，我会收到该错误:

If I try to use Spark after the previous error, I received that error:

ERROR:root:Exception发送命令时.追溯(最新最后调用):文件"/opt/conda/lib/python3.6/site-packages/py4j/java_gateway.py"，行1062，在send_command中引发Py4JNetworkError("Java端的答案为空")py4j.protocol.Py4JNetworkError:Java端的答案为空

ERROR:root:Exception while sending command. Traceback (most recent call last): File "/opt/conda/lib/python3.6/site-packages/py4j/java_gateway.py", line 1062, in send_command raise Py4JNetworkError("Answer from Java side is empty") py4j.protocol.Py4JNetworkError: Answer from Java side is empty

在处理上述异常期间，发生了另一个异常:

During handling of the above exception, another exception occurred:

回溯(最近通话最近):文件"/opt/conda/lib/python3.6/site-packages/py4j/java_gateway.py"，行908，在send_command中响应= connection.send_command(命令)文件"/opt/conda/lib/python3.6/site-packages/py4j/java_gateway.py"，行1067，在send_command中py4j.protocol.Py4JNetworkError:接收时出错"，proto.ERROR_ON_RECEIVE)

Traceback (most recent call last): File "/opt/conda/lib/python3.6/site-packages/py4j/java_gateway.py", line 908, in send_command response = connection.send_command(command) File "/opt/conda/lib/python3.6/site-packages/py4j/java_gateway.py", line 1067, in send_command "Error while receiving", e, proto.ERROR_ON_RECEIVE) py4j.protocol.Py4JNetworkError: Error while receiving

推荐答案

我解决了这个问题！基本上，由于某种原因，该问题与Jupyter Notebook有关.我删除了先前代码的下一行:

I resolved the problem! Basically, the problem was related to Jupyter Notebook for some reason. I removed the next line of the previous code:

os.environ['PYSPARK_SUBMIT_ARGS'] = '--packages org.apache.spark:spark-sql-kafka-0-10_2.11:2.3.0 pyspark-shell'

然后我使用控制台运行代码:

And I ran the code using the console:

> spark-submit --packages org.apache.spark:spark-sql-kafka-0-10_2.11:2.3.0 spark_structured.py

这样，我可以毫无问题地运行所有代码.

In that way, I could run all the code without problems.

如果您遇到相同的问题，也可以更改 spark-default.conf ，并增加 spark.driver.memory 和 spark.executor.memory

In case of you have the same problem, you can also change the spark-default.conf and increase the spark.driver.memory and spark.executor.memory

这篇关于结构化流错误py4j.protocol.Py4JNetworkError:来自Java端的答案为空的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！