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1 | /* |
2 | * Licensed to the Apache Software Foundation (ASF) under one | |
3 | * or more contributor license agreements. See the NOTICE file | |
4 | * distributed with this work for additional information | |
5 | * regarding copyright ownership. The ASF licenses this file | |
6 | * to you under the Apache License, Version 2.0 (the | |
7 | * "License"); you may not use this file except in compliance | |
8 | * with the License. You may obtain a copy of the License at | |
9 | * | |
10 | * http://www.apache.org/licenses/LICENSE-2.0 | |
11 | * | |
12 | * Unless required by applicable law or agreed to in writing, | |
13 | * software distributed under the License is distributed on an | |
14 | * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY | |
15 | * KIND, either express or implied. See the License for the | |
16 | * specific language governing permissions and limitations | |
17 | * under the License. | |
18 | */ | |
19 | module thrift.server.taskpool; | |
20 | ||
21 | import core.sync.condition; | |
22 | import core.sync.mutex; | |
23 | import std.exception : enforce; | |
24 | import std.parallelism; | |
25 | import std.variant : Variant; | |
26 | import thrift.base; | |
27 | import thrift.protocol.base; | |
28 | import thrift.protocol.processor; | |
29 | import thrift.server.base; | |
30 | import thrift.server.transport.base; | |
31 | import thrift.transport.base; | |
32 | import thrift.util.cancellation; | |
33 | ||
34 | /** | |
35 | * A server which dispatches client requests to a std.parallelism TaskPool. | |
36 | */ | |
37 | class TTaskPoolServer : TServer { | |
38 | /// | |
39 | this( | |
40 | TProcessor processor, | |
41 | TServerTransport serverTransport, | |
42 | TTransportFactory transportFactory, | |
43 | TProtocolFactory protocolFactory, | |
44 | TaskPool taskPool = null | |
45 | ) { | |
46 | this(processor, serverTransport, transportFactory, transportFactory, | |
47 | protocolFactory, protocolFactory, taskPool); | |
48 | } | |
49 | ||
50 | /// | |
51 | this( | |
52 | TProcessorFactory processorFactory, | |
53 | TServerTransport serverTransport, | |
54 | TTransportFactory transportFactory, | |
55 | TProtocolFactory protocolFactory, | |
56 | TaskPool taskPool = null | |
57 | ) { | |
58 | this(processorFactory, serverTransport, transportFactory, transportFactory, | |
59 | protocolFactory, protocolFactory, taskPool); | |
60 | } | |
61 | ||
62 | /// | |
63 | this( | |
64 | TProcessor processor, | |
65 | TServerTransport serverTransport, | |
66 | TTransportFactory inputTransportFactory, | |
67 | TTransportFactory outputTransportFactory, | |
68 | TProtocolFactory inputProtocolFactory, | |
69 | TProtocolFactory outputProtocolFactory, | |
70 | TaskPool taskPool = null | |
71 | ) { | |
72 | this(new TSingletonProcessorFactory(processor), serverTransport, | |
73 | inputTransportFactory, outputTransportFactory, | |
74 | inputProtocolFactory, outputProtocolFactory); | |
75 | } | |
76 | ||
77 | /// | |
78 | this( | |
79 | TProcessorFactory processorFactory, | |
80 | TServerTransport serverTransport, | |
81 | TTransportFactory inputTransportFactory, | |
82 | TTransportFactory outputTransportFactory, | |
83 | TProtocolFactory inputProtocolFactory, | |
84 | TProtocolFactory outputProtocolFactory, | |
85 | TaskPool taskPool = null | |
86 | ) { | |
87 | super(processorFactory, serverTransport, inputTransportFactory, | |
88 | outputTransportFactory, inputProtocolFactory, outputProtocolFactory); | |
89 | ||
90 | if (taskPool) { | |
91 | this.taskPool = taskPool; | |
92 | } else { | |
93 | auto ptp = std.parallelism.taskPool; | |
94 | if (ptp.size > 0) { | |
95 | taskPool_ = ptp; | |
96 | } else { | |
97 | // If the global task pool is empty (default on a single-core machine), | |
98 | // create a new one with a single worker thread. The rationale for this | |
99 | // is to avoid that an application which worked fine with no task pool | |
100 | // explicitly set on the multi-core developer boxes suddenly fails on a | |
101 | // single-core user machine. | |
102 | taskPool_ = new TaskPool(1); | |
103 | taskPool_.isDaemon = true; | |
104 | } | |
105 | } | |
106 | } | |
107 | ||
108 | override void serve(TCancellation cancellation = null) { | |
109 | serverTransport_.listen(); | |
110 | ||
111 | if (eventHandler) eventHandler.preServe(); | |
112 | ||
113 | auto queueState = QueueState(); | |
114 | ||
115 | while (true) { | |
116 | // Check if we can still handle more connections. | |
117 | if (maxActiveConns) { | |
118 | synchronized (queueState.mutex) { | |
119 | while (queueState.activeConns >= maxActiveConns) { | |
120 | queueState.connClosed.wait(); | |
121 | } | |
122 | } | |
123 | } | |
124 | ||
125 | TTransport client; | |
126 | TTransport inputTransport; | |
127 | TTransport outputTransport; | |
128 | TProtocol inputProtocol; | |
129 | TProtocol outputProtocol; | |
130 | ||
131 | try { | |
132 | client = serverTransport_.accept(cancellation); | |
133 | scope(failure) client.close(); | |
134 | ||
135 | inputTransport = inputTransportFactory_.getTransport(client); | |
136 | scope(failure) inputTransport.close(); | |
137 | ||
138 | outputTransport = outputTransportFactory_.getTransport(client); | |
139 | scope(failure) outputTransport.close(); | |
140 | ||
141 | inputProtocol = inputProtocolFactory_.getProtocol(inputTransport); | |
142 | outputProtocol = outputProtocolFactory_.getProtocol(outputTransport); | |
143 | } catch (TCancelledException tce) { | |
144 | break; | |
145 | } catch (TTransportException ttx) { | |
146 | logError("TServerTransport failed on accept: %s", ttx); | |
147 | continue; | |
148 | } catch (TException tx) { | |
149 | logError("Caught TException on accept: %s", tx); | |
150 | continue; | |
151 | } | |
152 | ||
153 | auto info = TConnectionInfo(inputProtocol, outputProtocol, client); | |
154 | auto processor = processorFactory_.getProcessor(info); | |
155 | ||
156 | synchronized (queueState.mutex) { | |
157 | ++queueState.activeConns; | |
158 | } | |
159 | taskPool_.put(task!worker(queueState, client, inputProtocol, | |
160 | outputProtocol, processor, eventHandler)); | |
161 | } | |
162 | ||
163 | // First, stop accepting new connections. | |
164 | try { | |
165 | serverTransport_.close(); | |
166 | } catch (TServerTransportException e) { | |
167 | logError("Server transport failed to close: %s", e); | |
168 | } | |
169 | ||
170 | // Then, wait until all active connections are finished. | |
171 | synchronized (queueState.mutex) { | |
172 | while (queueState.activeConns > 0) { | |
173 | queueState.connClosed.wait(); | |
174 | } | |
175 | } | |
176 | } | |
177 | ||
178 | /** | |
179 | * Sets the task pool to use. | |
180 | * | |
181 | * By default, the global std.parallelism taskPool instance is used, which | |
182 | * might not be appropriate for many applications, e.g. where tuning the | |
183 | * number of worker threads is desired. (On single-core systems, a private | |
184 | * task pool with a single thread is used by default, since the global | |
185 | * taskPool instance has no worker threads then.) | |
186 | * | |
187 | * Note: TTaskPoolServer expects that tasks are never dropped from the pool, | |
188 | * e.g. by calling TaskPool.close() while there are still tasks in the | |
189 | * queue. If this happens, serve() will never return. | |
190 | */ | |
191 | void taskPool(TaskPool pool) @property { | |
192 | enforce(pool !is null, "Cannot use a null task pool."); | |
193 | enforce(pool.size > 0, "Cannot use a task pool with no worker threads."); | |
194 | taskPool_ = pool; | |
195 | } | |
196 | ||
197 | /** | |
198 | * The maximum number of client connections open at the same time. Zero for | |
199 | * no limit, which is the default. | |
200 | * | |
201 | * If this limit is reached, no clients are accept()ed from the server | |
202 | * transport any longer until another connection has been closed again. | |
203 | */ | |
204 | size_t maxActiveConns; | |
205 | ||
206 | protected: | |
207 | TaskPool taskPool_; | |
208 | } | |
209 | ||
210 | // Cannot be private as worker has to be passed as alias parameter to | |
211 | // another module. | |
212 | // private { | |
213 | /* | |
214 | * The state of the »connection queue«, i.e. used for keeping track of how | |
215 | * many client connections are currently processed. | |
216 | */ | |
217 | struct QueueState { | |
218 | /// Protects the queue state. | |
219 | Mutex mutex; | |
220 | ||
221 | /// The number of active connections (from the time they are accept()ed | |
222 | /// until they are closed when the worked task finishes). | |
223 | size_t activeConns; | |
224 | ||
225 | /// Signals that the number of active connections has been decreased, i.e. | |
226 | /// that a connection has been closed. | |
227 | Condition connClosed; | |
228 | ||
229 | /// Returns an initialized instance. | |
230 | static QueueState opCall() { | |
231 | QueueState q; | |
232 | q.mutex = new Mutex; | |
233 | q.connClosed = new Condition(q.mutex); | |
234 | return q; | |
235 | } | |
236 | } | |
237 | ||
238 | void worker(ref QueueState queueState, TTransport client, | |
239 | TProtocol inputProtocol, TProtocol outputProtocol, | |
240 | TProcessor processor, TServerEventHandler eventHandler) | |
241 | { | |
242 | scope (exit) { | |
243 | synchronized (queueState.mutex) { | |
244 | assert(queueState.activeConns > 0); | |
245 | --queueState.activeConns; | |
246 | queueState.connClosed.notifyAll(); | |
247 | } | |
248 | } | |
249 | ||
250 | Variant connectionContext; | |
251 | if (eventHandler) { | |
252 | connectionContext = | |
253 | eventHandler.createContext(inputProtocol, outputProtocol); | |
254 | } | |
255 | ||
256 | try { | |
257 | while (true) { | |
258 | if (eventHandler) { | |
259 | eventHandler.preProcess(connectionContext, client); | |
260 | } | |
261 | ||
262 | if (!processor.process(inputProtocol, outputProtocol, | |
263 | connectionContext) || !inputProtocol.transport.peek() | |
264 | ) { | |
265 | // Something went fundamentlly wrong or there is nothing more to | |
266 | // process, close the connection. | |
267 | break; | |
268 | } | |
269 | } | |
270 | } catch (TTransportException ttx) { | |
271 | if (ttx.type() != TTransportException.Type.END_OF_FILE) { | |
272 | logError("Client died unexpectedly: %s", ttx); | |
273 | } | |
274 | } catch (Exception e) { | |
275 | logError("Uncaught exception: %s", e); | |
276 | } | |
277 | ||
278 | if (eventHandler) { | |
279 | eventHandler.deleteContext(connectionContext, inputProtocol, | |
280 | outputProtocol); | |
281 | } | |
282 | ||
283 | try { | |
284 | inputProtocol.transport.close(); | |
285 | } catch (TTransportException ttx) { | |
286 | logError("Input close failed: %s", ttx); | |
287 | } | |
288 | try { | |
289 | outputProtocol.transport.close(); | |
290 | } catch (TTransportException ttx) { | |
291 | logError("Output close failed: %s", ttx); | |
292 | } | |
293 | try { | |
294 | client.close(); | |
295 | } catch (TTransportException ttx) { | |
296 | logError("Client close failed: %s", ttx); | |
297 | } | |
298 | } | |
299 | // } | |
300 | ||
301 | unittest { | |
302 | import thrift.internal.test.server; | |
303 | testServeCancel!TTaskPoolServer(); | |
304 | } |