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
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
|
/*
* 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.network.client;
import java.io.Closeable;
import java.io.IOException;
import java.util.UUID;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.TimeUnit;
import com.google.common.base.Objects;
import com.google.common.base.Preconditions;
import com.google.common.base.Throwables;
import com.google.common.util.concurrent.SettableFuture;
import io.netty.channel.Channel;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.spark.network.protocol.ChunkFetchRequest;
import org.apache.spark.network.protocol.RpcRequest;
import org.apache.spark.network.protocol.StreamChunkId;
import org.apache.spark.network.util.NettyUtils;
/**
* Client for fetching consecutive chunks of a pre-negotiated stream. This API is intended to allow
* efficient transfer of a large amount of data, broken up into chunks with size ranging from
* hundreds of KB to a few MB.
*
* Note that while this client deals with the fetching of chunks from a stream (i.e., data plane),
* the actual setup of the streams is done outside the scope of the transport layer. The convenience
* method "sendRPC" is provided to enable control plane communication between the client and server
* to perform this setup.
*
* For example, a typical workflow might be:
* client.sendRPC(new OpenFile("/foo")) --> returns StreamId = 100
* client.fetchChunk(streamId = 100, chunkIndex = 0, callback)
* client.fetchChunk(streamId = 100, chunkIndex = 1, callback)
* ...
* client.sendRPC(new CloseStream(100))
*
* Construct an instance of TransportClient using {@link TransportClientFactory}. A single
* TransportClient may be used for multiple streams, but any given stream must be restricted to a
* single client, in order to avoid out-of-order responses.
*
* NB: This class is used to make requests to the server, while {@link TransportResponseHandler} is
* responsible for handling responses from the server.
*
* Concurrency: thread safe and can be called from multiple threads.
*/
public class TransportClient implements Closeable {
private final Logger logger = LoggerFactory.getLogger(TransportClient.class);
private final Channel channel;
private final TransportResponseHandler handler;
public TransportClient(Channel channel, TransportResponseHandler handler) {
this.channel = Preconditions.checkNotNull(channel);
this.handler = Preconditions.checkNotNull(handler);
}
public boolean isActive() {
return channel.isOpen() || channel.isActive();
}
/**
* Requests a single chunk from the remote side, from the pre-negotiated streamId.
*
* Chunk indices go from 0 onwards. It is valid to request the same chunk multiple times, though
* some streams may not support this.
*
* Multiple fetchChunk requests may be outstanding simultaneously, and the chunks are guaranteed
* to be returned in the same order that they were requested, assuming only a single
* TransportClient is used to fetch the chunks.
*
* @param streamId Identifier that refers to a stream in the remote StreamManager. This should
* be agreed upon by client and server beforehand.
* @param chunkIndex 0-based index of the chunk to fetch
* @param callback Callback invoked upon successful receipt of chunk, or upon any failure.
*/
public void fetchChunk(
long streamId,
final int chunkIndex,
final ChunkReceivedCallback callback) {
final String serverAddr = NettyUtils.getRemoteAddress(channel);
final long startTime = System.currentTimeMillis();
logger.debug("Sending fetch chunk request {} to {}", chunkIndex, serverAddr);
final StreamChunkId streamChunkId = new StreamChunkId(streamId, chunkIndex);
handler.addFetchRequest(streamChunkId, callback);
channel.writeAndFlush(new ChunkFetchRequest(streamChunkId)).addListener(
new ChannelFutureListener() {
@Override
public void operationComplete(ChannelFuture future) throws Exception {
if (future.isSuccess()) {
long timeTaken = System.currentTimeMillis() - startTime;
logger.trace("Sending request {} to {} took {} ms", streamChunkId, serverAddr,
timeTaken);
} else {
String errorMsg = String.format("Failed to send request %s to %s: %s", streamChunkId,
serverAddr, future.cause());
logger.error(errorMsg, future.cause());
handler.removeFetchRequest(streamChunkId);
channel.close();
try {
callback.onFailure(chunkIndex, new IOException(errorMsg, future.cause()));
} catch (Exception e) {
logger.error("Uncaught exception in RPC response callback handler!", e);
}
}
}
});
}
/**
* Sends an opaque message to the RpcHandler on the server-side. The callback will be invoked
* with the server's response or upon any failure.
*/
public void sendRpc(byte[] message, final RpcResponseCallback callback) {
final String serverAddr = NettyUtils.getRemoteAddress(channel);
final long startTime = System.currentTimeMillis();
logger.trace("Sending RPC to {}", serverAddr);
final long requestId = Math.abs(UUID.randomUUID().getLeastSignificantBits());
handler.addRpcRequest(requestId, callback);
channel.writeAndFlush(new RpcRequest(requestId, message)).addListener(
new ChannelFutureListener() {
@Override
public void operationComplete(ChannelFuture future) throws Exception {
if (future.isSuccess()) {
long timeTaken = System.currentTimeMillis() - startTime;
logger.trace("Sending request {} to {} took {} ms", requestId, serverAddr, timeTaken);
} else {
String errorMsg = String.format("Failed to send RPC %s to %s: %s", requestId,
serverAddr, future.cause());
logger.error(errorMsg, future.cause());
handler.removeRpcRequest(requestId);
channel.close();
try {
callback.onFailure(new IOException(errorMsg, future.cause()));
} catch (Exception e) {
logger.error("Uncaught exception in RPC response callback handler!", e);
}
}
}
});
}
/**
* Synchronously sends an opaque message to the RpcHandler on the server-side, waiting for up to
* a specified timeout for a response.
*/
public byte[] sendRpcSync(byte[] message, long timeoutMs) {
final SettableFuture<byte[]> result = SettableFuture.create();
sendRpc(message, new RpcResponseCallback() {
@Override
public void onSuccess(byte[] response) {
result.set(response);
}
@Override
public void onFailure(Throwable e) {
result.setException(e);
}
});
try {
return result.get(timeoutMs, TimeUnit.MILLISECONDS);
} catch (ExecutionException e) {
throw Throwables.propagate(e.getCause());
} catch (Exception e) {
throw Throwables.propagate(e);
}
}
@Override
public void close() {
// close is a local operation and should finish with milliseconds; timeout just to be safe
channel.close().awaitUninterruptibly(10, TimeUnit.SECONDS);
}
@Override
public String toString() {
return Objects.toStringHelper(this)
.add("remoteAdress", channel.remoteAddress())
.add("isActive", isActive())
.toString();
}
}
|
