39 lines
1.4 KiB
Python
39 lines
1.4 KiB
Python
import os
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import sys
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from subprocess import Popen, PIPE
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from threading import Thread
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from py4j.java_gateway import java_import, JavaGateway, GatewayClient
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SPARK_HOME = os.environ["SPARK_HOME"]
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def launch_gateway():
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# Launch the Py4j gateway using Spark's run command so that we pick up the
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# proper classpath and SPARK_MEM settings from spark-env.sh
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command = [os.path.join(SPARK_HOME, "run"), "py4j.GatewayServer",
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"--die-on-broken-pipe", "0"]
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proc = Popen(command, stdout=PIPE, stdin=PIPE)
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# Determine which ephemeral port the server started on:
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port = int(proc.stdout.readline())
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# Create a thread to echo output from the GatewayServer, which is required
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# for Java log output to show up:
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class EchoOutputThread(Thread):
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def __init__(self, stream):
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Thread.__init__(self)
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self.daemon = True
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self.stream = stream
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def run(self):
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while True:
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line = self.stream.readline()
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sys.stderr.write(line)
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EchoOutputThread(proc.stdout).start()
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# Connect to the gateway
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gateway = JavaGateway(GatewayClient(port=port), auto_convert=False)
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# Import the classes used by PySpark
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java_import(gateway.jvm, "spark.api.java.*")
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java_import(gateway.jvm, "spark.api.python.*")
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java_import(gateway.jvm, "scala.Tuple2")
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return gateway
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