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/*
* 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.dstream
import java.io._
import java.net.{ConnectException, Socket}
import java.nio.charset.StandardCharsets
import scala.reflect.ClassTag
import scala.util.control.NonFatal
import org.apache.spark.internal.Logging
import org.apache.spark.storage.StorageLevel
import org.apache.spark.streaming.StreamingContext
import org.apache.spark.streaming.receiver.Receiver
import org.apache.spark.util.NextIterator
private[streaming]
class SocketInputDStream[T: ClassTag](
_ssc: StreamingContext,
host: String,
port: Int,
bytesToObjects: InputStream => Iterator[T],
storageLevel: StorageLevel
) extends ReceiverInputDStream[T](_ssc) {
def getReceiver(): Receiver[T] = {
new SocketReceiver(host, port, bytesToObjects, storageLevel)
}
}
private[streaming]
class SocketReceiver[T: ClassTag](
host: String,
port: Int,
bytesToObjects: InputStream => Iterator[T],
storageLevel: StorageLevel
) extends Receiver[T](storageLevel) with Logging {
private var socket: Socket = _
def onStart(): Unit = {
logInfo(s"Connecting to $host:$port")
try {
socket = new Socket(host, port)
} catch {
case e: ConnectException =>
restart(s"Error connecting to $host:$port", e)
return
}
logInfo(s"Connected to $host:$port")
// Start the thread that receives data over a connection
new Thread("Socket Receiver") {
setDaemon(true)
override def run(): Unit = { receive() }
}.start()
}
def onStop(): Unit = {
// in case restart thread close it twice
synchronized {
if (socket != null) {
socket.close()
socket = null
logInfo(s"Closed socket to $host:$port")
}
}
}
/** Create a socket connection and receive data until receiver is stopped */
def receive(): Unit = {
try {
val iterator = bytesToObjects(socket.getInputStream())
while(!isStopped && iterator.hasNext) {
store(iterator.next())
}
if (!isStopped()) {
restart("Socket data stream had no more data")
} else {
logInfo("Stopped receiving")
}
} catch {
case NonFatal(e) =>
logWarning("Error receiving data", e)
restart("Error receiving data", e)
} finally {
onStop()
}
}
}
private[streaming]
object SocketReceiver {
/**
* This methods translates the data from an inputstream (say, from a socket)
* to '\n' delimited strings and returns an iterator to access the strings.
*/
def bytesToLines(inputStream: InputStream): Iterator[String] = {
val dataInputStream = new BufferedReader(
new InputStreamReader(inputStream, StandardCharsets.UTF_8))
new NextIterator[String] {
protected override def getNext() = {
val nextValue = dataInputStream.readLine()
if (nextValue == null) {
finished = true
}
nextValue
}
protected override def close(): Unit = {
dataInputStream.close()
}
}
}
}
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