Github user tdas commented on a diff in the pull request:
https://github.com/apache/spark/pull/2538#discussion_r18235476
--- Diff:
streaming/src/main/scala/org/apache/spark/streaming/api/python/PythonDStream.scala
---
@@ -0,0 +1,275 @@
+/*
+ * 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.
+ */
+
+package org.apache.spark.streaming.api.python
+
+import java.util.{ArrayList => JArrayList, List => JList}
+import scala.collection.JavaConversions._
+import scala.collection.JavaConverters._
+import scala.collection.mutable
+
+import org.apache.spark.api.java._
+import org.apache.spark.api.python._
+import org.apache.spark.rdd.RDD
+import org.apache.spark.storage.StorageLevel
+import org.apache.spark.streaming.{Interval, Duration, Time}
+import org.apache.spark.streaming.dstream._
+import org.apache.spark.streaming.api.java._
+
+
+/**
+ * Interface for Python callback function with three arguments
+ */
+private[python] trait PythonRDDFunction {
+ // callback in Python
+ def call(time: Long, rdds: JList[_]): JavaRDD[Array[Byte]]
+}
+
+/**
+ * Wrapper for PythonRDDFunction
+ */
+private[python] class RDDFunction(pfunc: PythonRDDFunction)
+ extends function.Function2[JList[JavaRDD[_]], Time,
JavaRDD[Array[Byte]]] with Serializable {
+
+ def apply(rdd: Option[RDD[_]], time: Time): Option[RDD[Array[Byte]]] = {
+ PythonDStream.some(pfunc.call(time.milliseconds,
List(PythonDStream.wrapRDD(rdd)).asJava))
+ }
+
+ def apply(rdd: Option[RDD[_]], rdd2: Option[RDD[_]], time: Time):
Option[RDD[Array[Byte]]] = {
+ val rdds = List(PythonDStream.wrapRDD(rdd),
PythonDStream.wrapRDD(rdd2)).asJava
+ PythonDStream.some(pfunc.call(time.milliseconds, rdds))
+ }
+
+ // for function.Function2
+ def call(rdds: JList[JavaRDD[_]], time: Time): JavaRDD[Array[Byte]] = {
+ pfunc.call(time.milliseconds, rdds)
+ }
+}
+
+
+/**
+ * Base class for PythonDStream with some common methods
+ */
+private[python]
+abstract class PythonDStream(parent: DStream[_], pfunc: PythonRDDFunction)
+ extends DStream[Array[Byte]] (parent.ssc) {
+
+ val func = new RDDFunction(pfunc)
+
+ override def dependencies = List(parent)
+
+ override def slideDuration: Duration = parent.slideDuration
+
+ val asJavaDStream = JavaDStream.fromDStream(this)
+}
+
+/**
+ * Helper functions
+ */
+private[python] object PythonDStream {
+
+ // convert Option[RDD[_]] to JavaRDD, handle null gracefully
+ def wrapRDD(rdd: Option[RDD[_]]): JavaRDD[_] = {
+ if (rdd.isDefined) {
+ JavaRDD.fromRDD(rdd.get)
+ } else {
+ null
+ }
+ }
+
+ // convert JavaRDD to Option[RDD[Array[Byte]]] to , handle null
gracefully
+ def some(jrdd: JavaRDD[Array[Byte]]): Option[RDD[Array[Byte]]] = {
+ if (jrdd != null) {
+ Some(jrdd.rdd)
+ } else {
+ None
+ }
+ }
+
+ // helper function for DStream.foreachRDD(),
+ // cannot be `foreachRDD`, it will confusing py4j
+ def callForeachRDD(jdstream: JavaDStream[Array[Byte]], pfunc:
PythonRDDFunction){
+ val func = new RDDFunction((pfunc))
+ jdstream.dstream.foreachRDD((rdd, time) => func(Some(rdd), time))
+ }
+
+ // helper function for ssc.transform()
+ def callTransform(ssc: JavaStreamingContext, jdsteams:
JList[JavaDStream[_]],
+ pyfunc: PythonRDDFunction)
+ :JavaDStream[Array[Byte]] = {
+ val func = new RDDFunction(pyfunc)
+ ssc.transform(jdsteams, func)
+ }
+
+ // convert list of RDD into queue of RDDs, for ssc.queueStream()
+ def toRDDQueue(rdds: JArrayList[JavaRDD[Array[Byte]]]):
java.util.Queue[JavaRDD[Array[Byte]]] = {
+ val queue = new java.util.LinkedList[JavaRDD[Array[Byte]]]
+ rdds.forall(queue.add(_))
+ queue
+ }
+}
+
+/**
+ * Transformed DStream in Python.
+ *
+ * If `reuse` is true and the result of the `func` is an PythonRDD, then
it will cache it
+ * as an template for future use, this can reduce the Python callbacks.
+ */
+private[python]
+class PythonTransformedDStream (parent: DStream[_], pfunc:
PythonRDDFunction,
+ var reuse: Boolean = false)
+ extends PythonDStream(parent, pfunc) {
+
+ // rdd returned by func
+ var lastResult: PythonRDD = _
+
+ override def compute(validTime: Time): Option[RDD[Array[Byte]]] = {
+ val rdd = parent.getOrCompute(validTime)
+ if (rdd.isEmpty) {
+ return None
+ }
+ if (reuse && lastResult != null) {
+ // use the previous result as the template to generate new RDD
+ Some(lastResult.copyTo(rdd.get))
+ } else {
+ val r = func(rdd, validTime)
+ if (reuse && r.isDefined && lastResult == null) {
+ // try to use the result as a template
+ r.get match {
+ case pyrdd: PythonRDD =>
+ if (pyrdd.parent(0) == rdd) {
+ // only one PythonRDD
+ lastResult = pyrdd
+ } else {
+ // maybe have multiple stages, don't check it anymore
+ reuse = false
+ }
+ }
+ }
+ r
+ }
+ }
+}
+
+/**
+ * Transformed from two DStreams in Python.
+ */
+private[python]
+class PythonTransformed2DStream(parent: DStream[_], parent2: DStream[_],
+ pfunc: PythonRDDFunction)
+ extends DStream[Array[Byte]] (parent.ssc) {
+
+ val func = new RDDFunction(pfunc)
+
+ override def slideDuration: Duration = parent.slideDuration
+
+ override def dependencies = List(parent, parent2)
+
+ override def compute(validTime: Time): Option[RDD[Array[Byte]]] = {
+ func(parent.getOrCompute(validTime), parent2.getOrCompute(validTime),
validTime)
+ }
+
+ val asJavaDStream = JavaDStream.fromDStream(this)
--- End diff --
extra space.
---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at [email protected] or file a JIRA ticket
with INFRA.
---
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
