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1 | <?php |
2 | /* | |
3 | * Licensed to the Apache Software Foundation (ASF) under one | |
4 | * or more contributor license agreements. See the NOTICE file | |
5 | * distributed with this work for additional information | |
6 | * regarding copyright ownership. The ASF licenses this file | |
7 | * to you under the Apache License, Version 2.0 (the | |
8 | * "License"); you may not use this file except in compliance | |
9 | * with the License. You may obtain a copy of the License at | |
10 | * | |
11 | * http://www.apache.org/licenses/LICENSE-2.0 | |
12 | * | |
13 | * Unless required by applicable law or agreed to in writing, | |
14 | * software distributed under the License is distributed on an | |
15 | * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY | |
16 | * KIND, either express or implied. See the License for the | |
17 | * specific language governing permissions and limitations | |
18 | * under the License. | |
19 | * | |
20 | * @package thrift.transport | |
21 | */ | |
22 | ||
23 | namespace Thrift\Transport; | |
24 | ||
25 | use Thrift\Exception\TException; | |
26 | ||
27 | /** | |
28 | * This library makes use of APC cache to make hosts as down in a web | |
29 | * environment. If you are running from the CLI or on a system without APC | |
30 | * installed, then these null functions will step in and act like cache | |
31 | * misses. | |
32 | */ | |
33 | if (!function_exists('apc_fetch')) { | |
34 | function apc_fetch($key) | |
35 | { | |
36 | return false; | |
37 | } | |
38 | ||
39 | function apc_store($key, $var, $ttl = 0) | |
40 | { | |
41 | return false; | |
42 | } | |
43 | } | |
44 | ||
45 | /** | |
46 | * Sockets implementation of the TTransport interface that allows connection | |
47 | * to a pool of servers. | |
48 | * | |
49 | * @package thrift.transport | |
50 | */ | |
51 | class TSocketPool extends TSocket | |
52 | { | |
53 | /** | |
54 | * Remote servers. Array of associative arrays with 'host' and 'port' keys | |
55 | */ | |
56 | private $servers_ = array(); | |
57 | ||
58 | /** | |
59 | * How many times to retry each host in connect | |
60 | * | |
61 | * @var int | |
62 | */ | |
63 | private $numRetries_ = 1; | |
64 | ||
65 | /** | |
66 | * Retry interval in seconds, how long to not try a host if it has been | |
67 | * marked as down. | |
68 | * | |
69 | * @var int | |
70 | */ | |
71 | private $retryInterval_ = 60; | |
72 | ||
73 | /** | |
74 | * Max consecutive failures before marking a host down. | |
75 | * | |
76 | * @var int | |
77 | */ | |
78 | private $maxConsecutiveFailures_ = 1; | |
79 | ||
80 | /** | |
81 | * Try hosts in order? or Randomized? | |
82 | * | |
83 | * @var bool | |
84 | */ | |
85 | private $randomize_ = true; | |
86 | ||
87 | /** | |
88 | * Always try last host, even if marked down? | |
89 | * | |
90 | * @var bool | |
91 | */ | |
92 | private $alwaysTryLast_ = true; | |
93 | ||
94 | /** | |
95 | * Socket pool constructor | |
96 | * | |
97 | * @param array $hosts List of remote hostnames | |
98 | * @param mixed $ports Array of remote ports, or a single common port | |
99 | * @param bool $persist Whether to use a persistent socket | |
100 | * @param mixed $debugHandler Function for error logging | |
101 | */ | |
102 | public function __construct( | |
103 | $hosts = array('localhost'), | |
104 | $ports = array(9090), | |
105 | $persist = false, | |
106 | $debugHandler = null | |
107 | ) { | |
108 | parent::__construct(null, 0, $persist, $debugHandler); | |
109 | ||
110 | if (!is_array($ports)) { | |
111 | $port = $ports; | |
112 | $ports = array(); | |
113 | foreach ($hosts as $key => $val) { | |
114 | $ports[$key] = $port; | |
115 | } | |
116 | } | |
117 | ||
118 | foreach ($hosts as $key => $host) { | |
119 | $this->servers_ [] = array('host' => $host, | |
120 | 'port' => $ports[$key]); | |
121 | } | |
122 | } | |
123 | ||
124 | /** | |
125 | * Add a server to the pool | |
126 | * | |
127 | * This function does not prevent you from adding a duplicate server entry. | |
128 | * | |
129 | * @param string $host hostname or IP | |
130 | * @param int $port port | |
131 | */ | |
132 | public function addServer($host, $port) | |
133 | { | |
134 | $this->servers_[] = array('host' => $host, 'port' => $port); | |
135 | } | |
136 | ||
137 | /** | |
138 | * Sets how many time to keep retrying a host in the connect function. | |
139 | * | |
140 | * @param int $numRetries | |
141 | */ | |
142 | public function setNumRetries($numRetries) | |
143 | { | |
144 | $this->numRetries_ = $numRetries; | |
145 | } | |
146 | ||
147 | /** | |
148 | * Sets how long to wait until retrying a host if it was marked down | |
149 | * | |
150 | * @param int $numRetries | |
151 | */ | |
152 | public function setRetryInterval($retryInterval) | |
153 | { | |
154 | $this->retryInterval_ = $retryInterval; | |
155 | } | |
156 | ||
157 | /** | |
158 | * Sets how many time to keep retrying a host before marking it as down. | |
159 | * | |
160 | * @param int $numRetries | |
161 | */ | |
162 | public function setMaxConsecutiveFailures($maxConsecutiveFailures) | |
163 | { | |
164 | $this->maxConsecutiveFailures_ = $maxConsecutiveFailures; | |
165 | } | |
166 | ||
167 | /** | |
168 | * Turns randomization in connect order on or off. | |
169 | * | |
170 | * @param bool $randomize | |
171 | */ | |
172 | public function setRandomize($randomize) | |
173 | { | |
174 | $this->randomize_ = $randomize; | |
175 | } | |
176 | ||
177 | /** | |
178 | * Whether to always try the last server. | |
179 | * | |
180 | * @param bool $alwaysTryLast | |
181 | */ | |
182 | public function setAlwaysTryLast($alwaysTryLast) | |
183 | { | |
184 | $this->alwaysTryLast_ = $alwaysTryLast; | |
185 | } | |
186 | ||
187 | /** | |
188 | * Connects the socket by iterating through all the servers in the pool | |
189 | * and trying to find one that works. | |
190 | */ | |
191 | public function open() | |
192 | { | |
193 | // Check if we want order randomization | |
194 | if ($this->randomize_) { | |
195 | shuffle($this->servers_); | |
196 | } | |
197 | ||
198 | // Count servers to identify the "last" one | |
199 | $numServers = count($this->servers_); | |
200 | ||
201 | for ($i = 0; $i < $numServers; ++$i) { | |
202 | // This extracts the $host and $port variables | |
203 | extract($this->servers_[$i]); | |
204 | ||
205 | // Check APC cache for a record of this server being down | |
206 | $failtimeKey = 'thrift_failtime:' . $host . ':' . $port . '~'; | |
207 | ||
208 | // Cache miss? Assume it's OK | |
209 | $lastFailtime = apc_fetch($failtimeKey); | |
210 | if ($lastFailtime === false) { | |
211 | $lastFailtime = 0; | |
212 | } | |
213 | ||
214 | $retryIntervalPassed = false; | |
215 | ||
216 | // Cache hit...make sure enough the retry interval has elapsed | |
217 | if ($lastFailtime > 0) { | |
218 | $elapsed = time() - $lastFailtime; | |
219 | if ($elapsed > $this->retryInterval_) { | |
220 | $retryIntervalPassed = true; | |
221 | if ($this->debug_) { | |
222 | call_user_func( | |
223 | $this->debugHandler_, | |
224 | 'TSocketPool: retryInterval ' . | |
225 | '(' . $this->retryInterval_ . ') ' . | |
226 | 'has passed for host ' . $host . ':' . $port | |
227 | ); | |
228 | } | |
229 | } | |
230 | } | |
231 | ||
232 | // Only connect if not in the middle of a fail interval, OR if this | |
233 | // is the LAST server we are trying, just hammer away on it | |
234 | $isLastServer = false; | |
235 | if ($this->alwaysTryLast_) { | |
236 | $isLastServer = ($i == ($numServers - 1)); | |
237 | } | |
238 | ||
239 | if (($lastFailtime === 0) || | |
240 | ($isLastServer) || | |
241 | ($lastFailtime > 0 && $retryIntervalPassed)) { | |
242 | // Set underlying TSocket params to this one | |
243 | $this->host_ = $host; | |
244 | $this->port_ = $port; | |
245 | ||
246 | // Try up to numRetries_ connections per server | |
247 | for ($attempt = 0; $attempt < $this->numRetries_; $attempt++) { | |
248 | try { | |
249 | // Use the underlying TSocket open function | |
250 | parent::open(); | |
251 | ||
252 | // Only clear the failure counts if required to do so | |
253 | if ($lastFailtime > 0) { | |
254 | apc_store($failtimeKey, 0); | |
255 | } | |
256 | ||
257 | // Successful connection, return now | |
258 | return; | |
259 | } catch (TException $tx) { | |
260 | // Connection failed | |
261 | } | |
262 | } | |
263 | ||
264 | // Mark failure of this host in the cache | |
265 | $consecfailsKey = 'thrift_consecfails:' . $host . ':' . $port . '~'; | |
266 | ||
267 | // Ignore cache misses | |
268 | $consecfails = apc_fetch($consecfailsKey); | |
269 | if ($consecfails === false) { | |
270 | $consecfails = 0; | |
271 | } | |
272 | ||
273 | // Increment by one | |
274 | $consecfails++; | |
275 | ||
276 | // Log and cache this failure | |
277 | if ($consecfails >= $this->maxConsecutiveFailures_) { | |
278 | if ($this->debug_) { | |
279 | call_user_func( | |
280 | $this->debugHandler_, | |
281 | 'TSocketPool: marking ' . $host . ':' . $port . | |
282 | ' as down for ' . $this->retryInterval_ . ' secs ' . | |
283 | 'after ' . $consecfails . ' failed attempts.' | |
284 | ); | |
285 | } | |
286 | // Store the failure time | |
287 | apc_store($failtimeKey, time()); | |
288 | ||
289 | // Clear the count of consecutive failures | |
290 | apc_store($consecfailsKey, 0); | |
291 | } else { | |
292 | apc_store($consecfailsKey, $consecfails); | |
293 | } | |
294 | } | |
295 | } | |
296 | ||
297 | // Oh no; we failed them all. The system is totally ill! | |
298 | $error = 'TSocketPool: All hosts in pool are down. '; | |
299 | $hosts = array(); | |
300 | foreach ($this->servers_ as $server) { | |
301 | $hosts [] = $server['host'] . ':' . $server['port']; | |
302 | } | |
303 | $hostlist = implode(',', $hosts); | |
304 | $error .= '(' . $hostlist . ')'; | |
305 | if ($this->debug_) { | |
306 | call_user_func($this->debugHandler_, $error); | |
307 | } | |
308 | throw new TException($error); | |
309 | } | |
310 | } |