python/pyspark/java

# # Licensed to the Apache Software Foundation (ASF) under one or more # contributor license agreements. See the NOTICE file distributed with # this work for additional information regarding copyright ownership. # The ASF licenses this file to You under the Apache License, Version 2.0 # (the "License"); you may not use this file except in compliance with # the License. You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. # import atexit import os import signal import shlex import shutil import platform import tempfile import time from subprocess import Popen, PIPE from py4j.java_gateway import java_import, JavaGateway, JavaObject, GatewayParameters from py4j.clientserver import ClientServer, JavaParameters, PythonParameters from pyspark.serializers import read_int, UTF8Deserializer from pyspark.find_spark_home import _find_spark_home from pyspark.errors import PySparkRuntimeError # for backward compatibility references. from pyspark.util import local_connect_and_auth # noqa: F401 def launch_gateway(conf=None, popen_kwargs=None): """ launch jvm gateway Parameters ---------- conf : :py:class:`pyspark.SparkConf` spark configuration passed to spark-submit popen_kwargs : dict Dictionary of kwargs to pass to Popen when spawning the py4j JVM. This is a developer feature intended for use in customizing how pyspark interacts with the py4j JVM (e.g., capturing stdout/stderr). Returns ------- ClientServer or JavaGateway """ if "PYSPARK_GATEWAY_PORT" in os.environ: gateway_port = int(os.environ["PYSPARK_GATEWAY_PORT"]) gateway_secret = os.environ["PYSPARK_GATEWAY_SECRET"] # Process already exists proc = None else: SPARK_HOME = _find_spark_home() # Launch the Py4j gateway using Spark's run command so that we pick up the # proper classpath and settings from spark-env.sh on_windows = platform.system() == "Windows" script = "./bin/spark-submit.cmd" if on_windows else "./bin/spark-submit" command = [os.path.join(SPARK_HOME, script)] if conf: for k, v in conf.getAll(): command += ["--conf", "%s=%s" % (k, v)] submit_args = os.environ.get("PYSPARK_SUBMIT_ARGS", "pyspark-shell") if os.environ.get("SPARK_TESTING"): submit_args = " ".join(["--conf spark.ui.enabled=false", submit_args]) command = command + shlex.split(submit_args) # Create a temporary directory where the gateway server should write the connection # information. conn_info_dir = tempfile.mkdtemp() try: fd, conn_info_file = tempfile.mkstemp(dir=conn_info_dir) os.close(fd) os.unlink(conn_info_file) env = dict(os.environ) env["_PYSPARK_DRIVER_CONN_INFO_PATH"] = conn_info_file # Launch the Java gateway. popen_kwargs = {} if popen_kwargs is None else popen_kwargs # We open a pipe to stdin so that the Java gateway can die when the pipe is broken popen_kwargs["stdin"] = PIPE # We always set the necessary environment variables. popen_kwargs["env"] = env if not on_windows: # Don't send ctrl-c / SIGINT to the Java gateway: def preexec_func(): signal.signal(signal.SIGINT, signal.SIG_IGN) popen_kwargs["preexec_fn"] = preexec_func proc = Popen(command, **popen_kwargs) else: # preexec_fn not supported on Windows proc = Popen(command, **popen_kwargs) # Wait for the file to appear, or for the process to exit, whichever happens first. while not proc.poll() and not os.path.isfile(conn_info_file): time.sleep(0.1) if not os.path.isfile(conn_info_file): raise PySparkRuntimeError( errorClass="JAVA_GATEWAY_EXITED", messageParameters={}, ) with open(conn_info_file, "rb") as info: gateway_port = read_int(info) gateway_secret = UTF8Deserializer().loads(info) finally: shutil.rmtree(conn_info_dir) # In Windows, ensure the Java child processes do not linger after Python has exited. # In UNIX-based systems, the child process can kill itself on broken pipe (i.e. when # the parent process' stdin sends an EOF). In Windows, however, this is not possible # because java.lang.Process reads directly from the parent process' stdin, contending # with any opportunity to read an EOF from the parent. Note that this is only best # effort and will not take effect if the python process is violently terminated. if on_windows: # In Windows, the child process here is "spark-submit.cmd", not the JVM itself # (because the UNIX "exec" command is not available). This means we cannot simply # call proc.kill(), which kills only the "spark-submit.cmd" process but not the # JVMs. Instead, we use "taskkill" with the tree-kill option "/t" to terminate all # child processes in the tree (http://technet.microsoft.com/en-us/library/bb491009.aspx) def killChild(): Popen(["cmd", "/c", "taskkill", "/f", "/t", "/pid", str(proc.pid)]) atexit.register(killChild) # Connect to the gateway (or client server to pin the thread between JVM and Python) if os.environ.get("PYSPARK_PIN_THREAD", "true").lower() == "true": gateway = ClientServer( java_parameters=JavaParameters( port=gateway_port, auth_token=gateway_secret, auto_convert=True ), python_parameters=PythonParameters(port=0, eager_load=False), ) else: gateway = JavaGateway( gateway_parameters=GatewayParameters( port=gateway_port, auth_token=gateway_secret, auto_convert=True ) ) # Store a reference to the Popen object for use by the caller (e.g., in reading stdout/stderr) gateway.proc = proc # Import the classes used by PySpark java_import(gateway.jvm, "org.apache.spark.SparkConf") java_import(gateway.jvm, "org.apache.spark.api.java.*") java_import(gateway.jvm, "org.apache.spark.api.python.*") java_import(gateway.jvm, "org.apache.spark.ml.python.*") java_import(gateway.jvm, "org.apache.spark.mllib.api.python.*") java_import(gateway.jvm, "org.apache.spark.resource.*") # TODO(davies): move into sql java_import(gateway.jvm, "org.apache.spark.sql.Encoders") java_import(gateway.jvm, "org.apache.spark.sql.OnSuccessCall") java_import(gateway.jvm, "org.apache.spark.sql.functions") java_import(gateway.jvm, "org.apache.spark.sql.classic.*") java_import(gateway.jvm, "org.apache.spark.sql.api.python.*") java_import(gateway.jvm, "org.apache.spark.sql.hive.*") java_import(gateway.jvm, "scala.Tuple2") return gateway def ensure_callback_server_started(gw): """ Start callback server if not already started. The callback server is needed if the Java driver process needs to callback into the Python driver process to execute Python code. """ # getattr will fallback to JVM, so we cannot test by hasattr() if "_callback_server" not in gw.__dict__ or gw._callback_server is None: gw.callback_server_parameters.eager_load = True gw.callback_server_parameters.daemonize = True gw.callback_server_parameters.daemonize_connections = True gw.callback_server_parameters.port = 0 gw.start_callback_server(gw.callback_server_parameters) cbport = gw._callback_server.server_socket.getsockname()[1] gw._callback_server.port = cbport # gateway with real port gw._python_proxy_port = gw._callback_server.port # get the GatewayServer object in JVM by ID jgws = JavaObject("GATEWAY_SERVER", gw._gateway_client) # update the port of CallbackClient with real port jgws.resetCallbackClient(jgws.getCallbackClient().getAddress(), gw._python_proxy_port)

python/pyspark/java_gateway.py (105 lines of code) (raw):