1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
|
/*
* 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.api.r
import java.io.{DataOutputStream, File, FileOutputStream, IOException}
import java.net.{InetAddress, InetSocketAddress, ServerSocket}
import java.util.concurrent.TimeUnit
import io.netty.bootstrap.ServerBootstrap
import io.netty.channel.{ChannelFuture, ChannelInitializer, ChannelOption, EventLoopGroup}
import io.netty.channel.nio.NioEventLoopGroup
import io.netty.channel.socket.SocketChannel
import io.netty.channel.socket.nio.NioServerSocketChannel
import io.netty.handler.codec.LengthFieldBasedFrameDecoder
import io.netty.handler.codec.bytes.{ByteArrayDecoder, ByteArrayEncoder}
import io.netty.handler.timeout.ReadTimeoutHandler
import org.apache.spark.SparkConf
import org.apache.spark.internal.Logging
/**
* Netty-based backend server that is used to communicate between R and Java.
*/
private[spark] class RBackend {
private[this] var channelFuture: ChannelFuture = null
private[this] var bootstrap: ServerBootstrap = null
private[this] var bossGroup: EventLoopGroup = null
def init(): Int = {
val conf = new SparkConf()
val backendConnectionTimeout = conf.getInt(
"spark.r.backendConnectionTimeout", SparkRDefaults.DEFAULT_CONNECTION_TIMEOUT)
bossGroup = new NioEventLoopGroup(
conf.getInt("spark.r.numRBackendThreads", SparkRDefaults.DEFAULT_NUM_RBACKEND_THREADS))
val workerGroup = bossGroup
val handler = new RBackendHandler(this)
bootstrap = new ServerBootstrap()
.group(bossGroup, workerGroup)
.channel(classOf[NioServerSocketChannel])
bootstrap.childHandler(new ChannelInitializer[SocketChannel]() {
def initChannel(ch: SocketChannel): Unit = {
ch.pipeline()
.addLast("encoder", new ByteArrayEncoder())
.addLast("frameDecoder",
// maxFrameLength = 2G
// lengthFieldOffset = 0
// lengthFieldLength = 4
// lengthAdjustment = 0
// initialBytesToStrip = 4, i.e. strip out the length field itself
new LengthFieldBasedFrameDecoder(Integer.MAX_VALUE, 0, 4, 0, 4))
.addLast("decoder", new ByteArrayDecoder())
.addLast("readTimeoutHandler", new ReadTimeoutHandler(backendConnectionTimeout))
.addLast("handler", handler)
}
})
channelFuture = bootstrap.bind(new InetSocketAddress("localhost", 0))
channelFuture.syncUninterruptibly()
channelFuture.channel().localAddress().asInstanceOf[InetSocketAddress].getPort()
}
def run(): Unit = {
channelFuture.channel.closeFuture().syncUninterruptibly()
}
def close(): Unit = {
if (channelFuture != null) {
// close is a local operation and should finish within milliseconds; timeout just to be safe
channelFuture.channel().close().awaitUninterruptibly(10, TimeUnit.SECONDS)
channelFuture = null
}
if (bootstrap != null && bootstrap.group() != null) {
bootstrap.group().shutdownGracefully()
}
if (bootstrap != null && bootstrap.childGroup() != null) {
bootstrap.childGroup().shutdownGracefully()
}
bootstrap = null
}
}
private[spark] object RBackend extends Logging {
initializeLogIfNecessary(true)
def main(args: Array[String]): Unit = {
if (args.length < 1) {
// scalastyle:off println
System.err.println("Usage: RBackend <tempFilePath>")
// scalastyle:on println
System.exit(-1)
}
val sparkRBackend = new RBackend()
try {
// bind to random port
val boundPort = sparkRBackend.init()
val serverSocket = new ServerSocket(0, 1, InetAddress.getByName("localhost"))
val listenPort = serverSocket.getLocalPort()
// Connection timeout is set by socket client. To make it configurable we will pass the
// timeout value to client inside the temp file
val conf = new SparkConf()
val backendConnectionTimeout = conf.getInt(
"spark.r.backendConnectionTimeout", SparkRDefaults.DEFAULT_CONNECTION_TIMEOUT)
// tell the R process via temporary file
val path = args(0)
val f = new File(path + ".tmp")
val dos = new DataOutputStream(new FileOutputStream(f))
dos.writeInt(boundPort)
dos.writeInt(listenPort)
SerDe.writeString(dos, RUtils.rPackages.getOrElse(""))
dos.writeInt(backendConnectionTimeout)
dos.close()
f.renameTo(new File(path))
// wait for the end of stdin, then exit
new Thread("wait for socket to close") {
setDaemon(true)
override def run(): Unit = {
// any un-catched exception will also shutdown JVM
val buf = new Array[Byte](1024)
// shutdown JVM if R does not connect back in 10 seconds
serverSocket.setSoTimeout(10000)
try {
val inSocket = serverSocket.accept()
serverSocket.close()
// wait for the end of socket, closed if R process die
inSocket.getInputStream().read(buf)
} finally {
sparkRBackend.close()
System.exit(0)
}
}
}.start()
sparkRBackend.run()
} catch {
case e: IOException =>
logError("Server shutting down: failed with exception ", e)
sparkRBackend.close()
System.exit(1)
}
System.exit(0)
}
}
|