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[m6w6/libmemcached] / libmemcached / hosts.cc
1 /* vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
2 *
3 * Libmemcached library
4 *
5 * Copyright (C) 2011 Data Differential, http://datadifferential.com/
6 * Copyright (C) 2006-2010 Brian Aker All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions are
10 * met:
11 *
12 * * Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 *
15 * * Redistributions in binary form must reproduce the above
16 * copyright notice, this list of conditions and the following disclaimer
17 * in the documentation and/or other materials provided with the
18 * distribution.
19 *
20 * * The names of its contributors may not be used to endorse or
21 * promote products derived from this software without specific prior
22 * written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
25 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
26 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
27 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
28 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
29 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
30 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
31 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
32 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
33 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
34 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
35 *
36 */
37
38 #include <libmemcached/common.h>
39
40 #include <cmath>
41 #include <sys/time.h>
42
43 /* Protoypes (static) */
44 static memcached_return_t update_continuum(memcached_st *ptr);
45
46 static int compare_servers(const void *p1, const void *p2)
47 {
48 int return_value;
49 memcached_server_instance_st a= (memcached_server_instance_st)p1;
50 memcached_server_instance_st b= (memcached_server_instance_st)p2;
51
52 return_value= strcmp(a->hostname, b->hostname);
53
54 if (return_value == 0)
55 {
56 return_value= (int) (a->port - b->port);
57 }
58
59 return return_value;
60 }
61
62 static void sort_hosts(memcached_st *ptr)
63 {
64 if (memcached_server_count(ptr))
65 {
66 memcached_server_write_instance_st instance;
67
68 qsort(memcached_server_list(ptr), memcached_server_count(ptr), sizeof(memcached_server_st), compare_servers);
69 instance= memcached_server_instance_fetch(ptr, 0);
70 instance->number_of_hosts= memcached_server_count(ptr);
71 }
72 }
73
74
75 memcached_return_t run_distribution(memcached_st *ptr)
76 {
77 if (ptr->flags.use_sort_hosts)
78 {
79 sort_hosts(ptr);
80 }
81
82 switch (ptr->distribution)
83 {
84 case MEMCACHED_DISTRIBUTION_CONSISTENT:
85 case MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA:
86 case MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA_SPY:
87 case MEMCACHED_DISTRIBUTION_CONSISTENT_WEIGHTED:
88 return update_continuum(ptr);
89
90 case MEMCACHED_DISTRIBUTION_VIRTUAL_BUCKET:
91 case MEMCACHED_DISTRIBUTION_MODULA:
92 break;
93
94 case MEMCACHED_DISTRIBUTION_RANDOM:
95 srandom((uint32_t) time(NULL));
96 break;
97
98 case MEMCACHED_DISTRIBUTION_CONSISTENT_MAX:
99 default:
100 assert_msg(0, "Invalid distribution type passed to run_distribution()");
101 }
102
103 return MEMCACHED_SUCCESS;
104 }
105
106 static uint32_t ketama_server_hash(const char *key, size_t key_length, uint32_t alignment)
107 {
108 unsigned char results[16];
109
110 libhashkit_md5_signature((unsigned char*)key, key_length, results);
111
112 return ((uint32_t) (results[3 + alignment * 4] & 0xFF) << 24)
113 | ((uint32_t) (results[2 + alignment * 4] & 0xFF) << 16)
114 | ((uint32_t) (results[1 + alignment * 4] & 0xFF) << 8)
115 | (results[0 + alignment * 4] & 0xFF);
116 }
117
118 static int continuum_item_cmp(const void *t1, const void *t2)
119 {
120 memcached_continuum_item_st *ct1= (memcached_continuum_item_st *)t1;
121 memcached_continuum_item_st *ct2= (memcached_continuum_item_st *)t2;
122
123 /* Why 153? Hmmm... */
124 WATCHPOINT_ASSERT(ct1->value != 153);
125 if (ct1->value == ct2->value)
126 return 0;
127 else if (ct1->value > ct2->value)
128 return 1;
129 else
130 return -1;
131 }
132
133 static memcached_return_t update_continuum(memcached_st *ptr)
134 {
135 uint32_t continuum_index= 0;
136 memcached_server_st *list;
137 uint32_t pointer_counter= 0;
138 uint32_t pointer_per_server= MEMCACHED_POINTS_PER_SERVER;
139 uint32_t pointer_per_hash= 1;
140 uint32_t live_servers= 0;
141 struct timeval now;
142
143 if (gettimeofday(&now, NULL))
144 {
145 return memcached_set_errno(*ptr, errno, MEMCACHED_AT);
146 }
147
148 list= memcached_server_list(ptr);
149
150 /* count live servers (those without a retry delay set) */
151 bool is_auto_ejecting= _is_auto_eject_host(ptr);
152 if (is_auto_ejecting)
153 {
154 live_servers= 0;
155 ptr->ketama.next_distribution_rebuild= 0;
156 for (uint32_t host_index= 0; host_index < memcached_server_count(ptr); ++host_index)
157 {
158 if (list[host_index].next_retry <= now.tv_sec)
159 {
160 live_servers++;
161 }
162 else
163 {
164 if (ptr->ketama.next_distribution_rebuild == 0 || list[host_index].next_retry < ptr->ketama.next_distribution_rebuild)
165 {
166 ptr->ketama.next_distribution_rebuild= list[host_index].next_retry;
167 }
168 }
169 }
170 }
171 else
172 {
173 live_servers= memcached_server_count(ptr);
174 }
175
176 uint64_t is_ketama_weighted= memcached_behavior_get(ptr, MEMCACHED_BEHAVIOR_KETAMA_WEIGHTED);
177 uint32_t points_per_server= (uint32_t) (is_ketama_weighted ? MEMCACHED_POINTS_PER_SERVER_KETAMA : MEMCACHED_POINTS_PER_SERVER);
178
179 if (not live_servers)
180 {
181 return MEMCACHED_SUCCESS;
182 }
183
184 if (live_servers > ptr->ketama.continuum_count)
185 {
186 memcached_continuum_item_st *new_ptr;
187
188 new_ptr= static_cast<memcached_continuum_item_st*>(libmemcached_realloc(ptr, ptr->ketama.continuum,
189 sizeof(memcached_continuum_item_st) * (live_servers + MEMCACHED_CONTINUUM_ADDITION) * points_per_server));
190
191 if (new_ptr == 0)
192 return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
193
194 ptr->ketama.continuum= new_ptr;
195 ptr->ketama.continuum_count= live_servers + MEMCACHED_CONTINUUM_ADDITION;
196 }
197
198 uint64_t total_weight= 0;
199 if (is_ketama_weighted)
200 {
201 for (uint32_t host_index = 0; host_index < memcached_server_count(ptr); ++host_index)
202 {
203 if (! is_auto_ejecting || list[host_index].next_retry <= now.tv_sec)
204 {
205 total_weight += list[host_index].weight;
206 }
207 }
208 }
209
210 for (uint32_t host_index= 0; host_index < memcached_server_count(ptr); ++host_index)
211 {
212 if (is_auto_ejecting && list[host_index].next_retry > now.tv_sec)
213 continue;
214
215 if (is_ketama_weighted)
216 {
217 float pct = (float)list[host_index].weight / (float)total_weight;
218 pointer_per_server= (uint32_t) ((floorf((float) (pct * MEMCACHED_POINTS_PER_SERVER_KETAMA / 4 * (float)live_servers + 0.0000000001))) * 4);
219 pointer_per_hash= 4;
220 #ifdef DEBUG
221 printf("ketama_weighted:%s|%d|%llu|%u\n",
222 list[host_index].hostname,
223 list[host_index].port,
224 (unsigned long long)list[host_index].weight,
225 pointer_per_server);
226 #endif
227 }
228
229
230 if (ptr->distribution == MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA_SPY)
231 {
232 for (uint32_t pointer_index= 0;
233 pointer_index < pointer_per_server / pointer_per_hash;
234 pointer_index++)
235 {
236 char sort_host[MEMCACHED_MAX_HOST_SORT_LENGTH]= "";
237 int sort_host_length;
238
239 // Spymemcached ketema key format is: hostname/ip:port-index
240 // If hostname is not available then: /ip:port-index
241 sort_host_length= snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH,
242 "/%s:%u-%u",
243 list[host_index].hostname,
244 (uint32_t)list[host_index].port,
245 pointer_index);
246
247 if (sort_host_length >= MEMCACHED_MAX_HOST_SORT_LENGTH || sort_host_length < 0)
248 {
249 return memcached_set_error(*ptr, MEMCACHED_MEMORY_ALLOCATION_FAILURE, MEMCACHED_AT,
250 memcached_literal_param("snprintf(MEMCACHED_DEFAULT_COMMAND_SIZE)"));
251 }
252 #ifdef DEBUG
253 printf("update_continuum: key is %s\n", sort_host);
254 #endif
255 if (is_ketama_weighted)
256 {
257 for (uint32_t x= 0; x < pointer_per_hash; x++)
258 {
259 uint32_t value= ketama_server_hash(sort_host, (size_t)sort_host_length, x);
260 ptr->ketama.continuum[continuum_index].index= host_index;
261 ptr->ketama.continuum[continuum_index++].value= value;
262 }
263 }
264 else
265 {
266 uint32_t value= hashkit_digest(&ptr->hashkit, sort_host, (size_t)sort_host_length);
267 ptr->ketama.continuum[continuum_index].index= host_index;
268 ptr->ketama.continuum[continuum_index++].value= value;
269 }
270 }
271 }
272 else
273 {
274 for (uint32_t pointer_index= 1;
275 pointer_index <= pointer_per_server / pointer_per_hash;
276 pointer_index++)
277 {
278 char sort_host[MEMCACHED_MAX_HOST_SORT_LENGTH]= "";
279 int sort_host_length;
280
281 if (list[host_index].port == MEMCACHED_DEFAULT_PORT)
282 {
283 sort_host_length= snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH,
284 "%s-%u",
285 list[host_index].hostname,
286 pointer_index - 1);
287 }
288 else
289 {
290 sort_host_length= snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH,
291 "%s:%u-%u",
292 list[host_index].hostname,
293 (uint32_t)list[host_index].port,
294 pointer_index - 1);
295 }
296
297 if (sort_host_length >= MEMCACHED_MAX_HOST_SORT_LENGTH || sort_host_length < 0)
298 {
299 return memcached_set_error(*ptr, MEMCACHED_MEMORY_ALLOCATION_FAILURE, MEMCACHED_AT,
300 memcached_literal_param("snprintf(MEMCACHED_DEFAULT_COMMAND_SIZE)"));
301 }
302
303 if (is_ketama_weighted)
304 {
305 for (uint32_t x = 0; x < pointer_per_hash; x++)
306 {
307 uint32_t value= ketama_server_hash(sort_host, (size_t)sort_host_length, x);
308 ptr->ketama.continuum[continuum_index].index= host_index;
309 ptr->ketama.continuum[continuum_index++].value= value;
310 }
311 }
312 else
313 {
314 uint32_t value= hashkit_digest(&ptr->hashkit, sort_host, (size_t)sort_host_length);
315 ptr->ketama.continuum[continuum_index].index= host_index;
316 ptr->ketama.continuum[continuum_index++].value= value;
317 }
318 }
319 }
320
321 pointer_counter+= pointer_per_server;
322 }
323
324 WATCHPOINT_ASSERT(ptr);
325 WATCHPOINT_ASSERT(ptr->ketama.continuum);
326 WATCHPOINT_ASSERT(memcached_server_count(ptr) * MEMCACHED_POINTS_PER_SERVER <= MEMCACHED_CONTINUUM_SIZE);
327 ptr->ketama.continuum_points_counter= pointer_counter;
328 qsort(ptr->ketama.continuum, ptr->ketama.continuum_points_counter, sizeof(memcached_continuum_item_st), continuum_item_cmp);
329
330 #ifdef DEBUG
331 for (uint32_t pointer_index= 0; memcached_server_count(ptr) && pointer_index < ((live_servers * MEMCACHED_POINTS_PER_SERVER) - 1); pointer_index++)
332 {
333 WATCHPOINT_ASSERT(ptr->ketama.continuum[pointer_index].value <= ptr->ketama.continuum[pointer_index + 1].value);
334 }
335 #endif
336
337 return MEMCACHED_SUCCESS;
338 }
339
340 static memcached_return_t server_add(memcached_st *ptr,
341 const memcached_string_t& hostname,
342 in_port_t port,
343 uint32_t weight,
344 memcached_connection_t type)
345 {
346 assert_msg(ptr, "Programmer mistake, somehow server_add() was passed a NULL memcached_st");
347 if ( (ptr->flags.use_udp and type != MEMCACHED_CONNECTION_UDP)
348 or ( (type == MEMCACHED_CONNECTION_UDP) and (not ptr->flags.use_udp) ) )
349 {
350 return memcached_set_error(*ptr, MEMCACHED_INVALID_HOST_PROTOCOL, MEMCACHED_AT);
351 }
352
353 memcached_server_st *new_host_list= static_cast<memcached_server_st*>(libmemcached_realloc(ptr, memcached_server_list(ptr),
354 sizeof(memcached_server_st) * (ptr->number_of_hosts + 1)));
355
356 if (not new_host_list)
357 {
358 return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
359 }
360
361 memcached_server_list_set(ptr, new_host_list);
362
363 /* TODO: Check return type */
364 memcached_server_write_instance_st instance= memcached_server_instance_fetch(ptr, memcached_server_count(ptr));
365
366 if (not __server_create_with(ptr, instance, hostname, port, weight, type))
367 {
368 return memcached_set_error(*ptr, MEMCACHED_MEMORY_ALLOCATION_FAILURE, MEMCACHED_AT);
369 }
370
371 if (weight > 1)
372 {
373 ptr->ketama.weighted= true;
374 }
375
376 ptr->number_of_hosts++;
377
378 // @note we place the count in the bottom of the server list
379 instance= memcached_server_instance_fetch(ptr, 0);
380 memcached_servers_set_count(instance, memcached_server_count(ptr));
381
382 return run_distribution(ptr);
383 }
384
385
386 memcached_return_t memcached_server_push(memcached_st *ptr, const memcached_server_list_st list)
387 {
388 if (not list)
389 {
390 return MEMCACHED_SUCCESS;
391 }
392
393 uint32_t count= memcached_server_list_count(list);
394
395 memcached_server_st *new_host_list;
396 new_host_list= static_cast<memcached_server_st*>(libmemcached_realloc(ptr, memcached_server_list(ptr),
397 sizeof(memcached_server_st) * (count + memcached_server_count(ptr))));
398
399 if (not new_host_list)
400 return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
401
402 memcached_server_list_set(ptr, new_host_list);
403
404 for (uint32_t x= 0; x < count; x++)
405 {
406 memcached_server_write_instance_st instance;
407
408 if ((ptr->flags.use_udp && list[x].type != MEMCACHED_CONNECTION_UDP)
409 or ((list[x].type == MEMCACHED_CONNECTION_UDP) and not (ptr->flags.use_udp)) )
410 {
411 return MEMCACHED_INVALID_HOST_PROTOCOL;
412 }
413
414 WATCHPOINT_ASSERT(list[x].hostname[0] != 0);
415
416 // We have extended the array, and now we will find it, and use it.
417 instance= memcached_server_instance_fetch(ptr, memcached_server_count(ptr));
418 WATCHPOINT_ASSERT(instance);
419
420 memcached_string_t hostname= { memcached_string_make_from_cstr(list[x].hostname) };
421 if (__server_create_with(ptr, instance,
422 hostname,
423 list[x].port, list[x].weight, list[x].type) == NULL)
424 {
425 return memcached_set_error(*ptr, MEMCACHED_MEMORY_ALLOCATION_FAILURE, MEMCACHED_AT);
426 }
427
428 if (list[x].weight > 1)
429 {
430 ptr->ketama.weighted= true;
431 }
432
433 ptr->number_of_hosts++;
434 }
435
436 // Provides backwards compatibility with server list.
437 {
438 memcached_server_write_instance_st instance;
439 instance= memcached_server_instance_fetch(ptr, 0);
440 instance->number_of_hosts= memcached_server_count(ptr);
441 }
442
443 return run_distribution(ptr);
444 }
445
446 memcached_return_t memcached_server_add_unix_socket(memcached_st *ptr,
447 const char *filename)
448 {
449 return memcached_server_add_unix_socket_with_weight(ptr, filename, 0);
450 }
451
452 memcached_return_t memcached_server_add_unix_socket_with_weight(memcached_st *ptr,
453 const char *filename,
454 uint32_t weight)
455 {
456 if (ptr == NULL)
457 {
458 return MEMCACHED_FAILURE;
459 }
460
461 memcached_string_t _filename= { memcached_string_make_from_cstr(filename) };
462 if (memcached_is_valid_servername(_filename) == false)
463 {
464 memcached_set_error(*ptr, MEMCACHED_INVALID_ARGUMENTS, MEMCACHED_AT, memcached_literal_param("Invalid filename for socket provided"));
465 }
466
467 return server_add(ptr, _filename, 0, weight, MEMCACHED_CONNECTION_UNIX_SOCKET);
468 }
469
470 memcached_return_t memcached_server_add_udp(memcached_st *ptr,
471 const char *hostname,
472 in_port_t port)
473 {
474 return memcached_server_add_udp_with_weight(ptr, hostname, port, 0);
475 }
476
477 memcached_return_t memcached_server_add_udp_with_weight(memcached_st *ptr,
478 const char *hostname,
479 in_port_t port,
480 uint32_t weight)
481 {
482 if (ptr == NULL)
483 {
484 return MEMCACHED_INVALID_ARGUMENTS;
485 }
486
487 if (not port)
488 {
489 port= MEMCACHED_DEFAULT_PORT;
490 }
491
492 if (not hostname)
493 {
494 hostname= "localhost";
495 }
496
497 memcached_string_t _hostname= { memcached_string_make_from_cstr(hostname) };
498 if (memcached_is_valid_servername(_hostname) == false)
499 {
500 memcached_set_error(*ptr, MEMCACHED_INVALID_ARGUMENTS, MEMCACHED_AT, memcached_literal_param("Invalid hostname provided"));
501 }
502
503 return server_add(ptr, _hostname, port, weight, MEMCACHED_CONNECTION_UDP);
504 }
505
506 memcached_return_t memcached_server_add(memcached_st *ptr,
507 const char *hostname,
508 in_port_t port)
509 {
510 return memcached_server_add_with_weight(ptr, hostname, port, 0);
511 }
512
513 memcached_return_t memcached_server_add_with_weight(memcached_st *ptr,
514 const char *hostname,
515 in_port_t port,
516 uint32_t weight)
517 {
518 if (ptr == NULL)
519 {
520 return MEMCACHED_INVALID_ARGUMENTS;
521 }
522
523 if (port == 0)
524 {
525 port= MEMCACHED_DEFAULT_PORT;
526 }
527
528 size_t hostname_length= hostname ? strlen(hostname) : 0;
529 if (hostname_length == 0)
530 {
531 hostname= "localhost";
532 hostname_length= sizeof("localhost") -1;
533 }
534
535 memcached_string_t _hostname= { hostname, hostname_length };
536
537 if (memcached_is_valid_servername(_hostname) == false)
538 {
539 return memcached_set_error(*ptr, MEMCACHED_INVALID_ARGUMENTS, MEMCACHED_AT, memcached_literal_param("Invalid hostname provided"));
540 }
541
542 return server_add(ptr, _hostname, port, weight, _hostname.c_str[0] == '/' ? MEMCACHED_CONNECTION_UNIX_SOCKET : MEMCACHED_CONNECTION_TCP);
543 }
544
545 memcached_return_t memcached_server_add_parsed(memcached_st *ptr,
546 const char *hostname,
547 size_t hostname_length,
548 in_port_t port,
549 uint32_t weight)
550 {
551 char buffer[NI_MAXHOST];
552
553 memcpy(buffer, hostname, hostname_length);
554 buffer[hostname_length]= 0;
555
556 memcached_string_t _hostname= { buffer, hostname_length };
557
558 return server_add(ptr, _hostname,
559 port,
560 weight,
561 MEMCACHED_CONNECTION_TCP);
562 }
Resurrection of libmemcached https://launchpad.net/libmemcached