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[awesomized/libmemcached] / libmemcached / hosts.c
1 /* LibMemcached
2 * Copyright (C) 2006-2010 Brian Aker
3 * All rights reserved.
4 *
5 * Use and distribution licensed under the BSD license. See
6 * the COPYING file in the parent directory for full text.
7 *
8 * Summary:
9 *
10 */
11
12 #include "common.h"
13 #include <math.h>
14
15 /* Protoypes (static) */
16 static memcached_return_t server_add(memcached_st *ptr, const char *hostname,
17 in_port_t port,
18 uint32_t weight,
19 memcached_connection_t type);
20 static memcached_return_t update_continuum(memcached_st *ptr);
21
22 static int compare_servers(const void *p1, const void *p2)
23 {
24 int return_value;
25 memcached_server_instance_st a= (memcached_server_instance_st)p1;
26 memcached_server_instance_st b= (memcached_server_instance_st)p2;
27
28 return_value= strcmp(a->hostname, b->hostname);
29
30 if (return_value == 0)
31 {
32 return_value= (int) (a->port - b->port);
33 }
34
35 return return_value;
36 }
37
38 static void sort_hosts(memcached_st *ptr)
39 {
40 if (memcached_server_count(ptr))
41 {
42 memcached_server_write_instance_st instance;
43
44 qsort(memcached_server_list(ptr), memcached_server_count(ptr), sizeof(memcached_server_st), compare_servers);
45 instance= memcached_server_instance_fetch(ptr, 0);
46 instance->number_of_hosts= memcached_server_count(ptr);
47 }
48 }
49
50
51 memcached_return_t run_distribution(memcached_st *ptr)
52 {
53 if (ptr->flags.use_sort_hosts)
54 sort_hosts(ptr);
55
56 switch (ptr->distribution)
57 {
58 case MEMCACHED_DISTRIBUTION_CONSISTENT:
59 case MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA:
60 case MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA_SPY:
61 return update_continuum(ptr);
62 case MEMCACHED_DISTRIBUTION_MODULA:
63 break;
64 case MEMCACHED_DISTRIBUTION_RANDOM:
65 srandom((uint32_t) time(NULL));
66 break;
67 case MEMCACHED_DISTRIBUTION_CONSISTENT_MAX:
68 default:
69 WATCHPOINT_ASSERT(0); /* We have added a distribution without extending the logic */
70 }
71
72 return MEMCACHED_SUCCESS;
73 }
74
75 static uint32_t ketama_server_hash(const char *key, size_t key_length, uint32_t alignment)
76 {
77 unsigned char results[16];
78
79 libhashkit_md5_signature((unsigned char*)key, key_length, results);
80
81 return ((uint32_t) (results[3 + alignment * 4] & 0xFF) << 24)
82 | ((uint32_t) (results[2 + alignment * 4] & 0xFF) << 16)
83 | ((uint32_t) (results[1 + alignment * 4] & 0xFF) << 8)
84 | (results[0 + alignment * 4] & 0xFF);
85 }
86
87 static int continuum_item_cmp(const void *t1, const void *t2)
88 {
89 memcached_continuum_item_st *ct1= (memcached_continuum_item_st *)t1;
90 memcached_continuum_item_st *ct2= (memcached_continuum_item_st *)t2;
91
92 /* Why 153? Hmmm... */
93 WATCHPOINT_ASSERT(ct1->value != 153);
94 if (ct1->value == ct2->value)
95 return 0;
96 else if (ct1->value > ct2->value)
97 return 1;
98 else
99 return -1;
100 }
101
102 static memcached_return_t update_continuum(memcached_st *ptr)
103 {
104 uint32_t host_index;
105 uint32_t continuum_index= 0;
106 uint32_t value;
107 memcached_server_st *list;
108 uint32_t pointer_index;
109 uint32_t pointer_counter= 0;
110 uint32_t pointer_per_server= MEMCACHED_POINTS_PER_SERVER;
111 uint32_t pointer_per_hash= 1;
112 uint64_t total_weight= 0;
113 uint64_t is_ketama_weighted= 0;
114 uint64_t is_auto_ejecting= 0;
115 uint32_t points_per_server= 0;
116 uint32_t live_servers= 0;
117 struct timeval now;
118
119 if (gettimeofday(&now, NULL) != 0)
120 {
121 ptr->cached_errno = errno;
122 return MEMCACHED_ERRNO;
123 }
124
125 list = memcached_server_list(ptr);
126
127 /* count live servers (those without a retry delay set) */
128 is_auto_ejecting= _is_auto_eject_host(ptr);
129 if (is_auto_ejecting)
130 {
131 live_servers= 0;
132 ptr->next_distribution_rebuild= 0;
133 for (host_index= 0; host_index < memcached_server_count(ptr); ++host_index)
134 {
135 if (list[host_index].next_retry <= now.tv_sec)
136 live_servers++;
137 else
138 {
139 if (ptr->next_distribution_rebuild == 0 || list[host_index].next_retry < ptr->next_distribution_rebuild)
140 ptr->next_distribution_rebuild= list[host_index].next_retry;
141 }
142 }
143 }
144 else
145 {
146 live_servers= memcached_server_count(ptr);
147 }
148
149 is_ketama_weighted= memcached_behavior_get(ptr, MEMCACHED_BEHAVIOR_KETAMA_WEIGHTED);
150 points_per_server= (uint32_t) (is_ketama_weighted ? MEMCACHED_POINTS_PER_SERVER_KETAMA : MEMCACHED_POINTS_PER_SERVER);
151
152 if (live_servers == 0)
153 return MEMCACHED_SUCCESS;
154
155 if (live_servers > ptr->continuum_count)
156 {
157 memcached_continuum_item_st *new_ptr;
158
159 new_ptr= libmemcached_realloc(ptr, ptr->continuum,
160 sizeof(memcached_continuum_item_st) * (live_servers + MEMCACHED_CONTINUUM_ADDITION) * points_per_server);
161
162 if (new_ptr == 0)
163 return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
164
165 ptr->continuum= new_ptr;
166 ptr->continuum_count= live_servers + MEMCACHED_CONTINUUM_ADDITION;
167 }
168
169 if (is_ketama_weighted)
170 {
171 for (host_index = 0; host_index < memcached_server_count(ptr); ++host_index)
172 {
173 if (list[host_index].weight == 0)
174 {
175 list[host_index].weight = 1;
176 }
177 if (! is_auto_ejecting || list[host_index].next_retry <= now.tv_sec)
178 total_weight += list[host_index].weight;
179 }
180 }
181
182 for (host_index= 0; host_index < memcached_server_count(ptr); ++host_index)
183 {
184 if (is_auto_ejecting && list[host_index].next_retry > now.tv_sec)
185 continue;
186
187 if (is_ketama_weighted)
188 {
189 float pct = (float)list[host_index].weight / (float)total_weight;
190 pointer_per_server= (uint32_t) ((floorf((float) (pct * MEMCACHED_POINTS_PER_SERVER_KETAMA / 4 * (float)live_servers + 0.0000000001))) * 4);
191 pointer_per_hash= 4;
192 #ifdef DEBUG
193 printf("ketama_weighted:%s|%d|%llu|%u\n",
194 list[host_index].hostname,
195 list[host_index].port,
196 (unsigned long long)list[host_index].weight,
197 pointer_per_server);
198 #endif
199 }
200
201
202 if (ptr->distribution == MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA_SPY)
203 {
204 for (pointer_index= 0;
205 pointer_index < pointer_per_server / pointer_per_hash;
206 pointer_index++)
207 {
208 char sort_host[MEMCACHED_MAX_HOST_SORT_LENGTH]= "";
209 size_t sort_host_length;
210
211 // Spymemcached ketema key format is: hostname/ip:port-index
212 // If hostname is not available then: /ip:port-index
213 sort_host_length= (size_t) snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH,
214 "/%s:%u-%u",
215 list[host_index].hostname,
216 (uint32_t)list[host_index].port,
217 pointer_index);
218 #ifdef DEBUG
219 printf("update_continuum: key is %s\n", sort_host);
220 #endif
221
222 WATCHPOINT_ASSERT(sort_host_length);
223
224 if (is_ketama_weighted)
225 {
226 for (uint32_t x= 0; x < pointer_per_hash; x++)
227 {
228 value= ketama_server_hash(sort_host, sort_host_length, x);
229 ptr->continuum[continuum_index].index= host_index;
230 ptr->continuum[continuum_index++].value= value;
231 }
232 }
233 else
234 {
235 value= hashkit_digest(&ptr->distribution_hashkit, sort_host, sort_host_length);
236 ptr->continuum[continuum_index].index= host_index;
237 ptr->continuum[continuum_index++].value= value;
238 }
239 }
240 }
241 else
242 {
243 for (pointer_index= 1;
244 pointer_index <= pointer_per_server / pointer_per_hash;
245 pointer_index++)
246 {
247 char sort_host[MEMCACHED_MAX_HOST_SORT_LENGTH]= "";
248 size_t sort_host_length;
249
250 if (list[host_index].port == MEMCACHED_DEFAULT_PORT)
251 {
252 sort_host_length= (size_t) snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH,
253 "%s-%u",
254 list[host_index].hostname,
255 pointer_index - 1);
256 }
257 else
258 {
259 sort_host_length= (size_t) snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH,
260 "%s:%u-%u",
261 list[host_index].hostname,
262 (uint32_t)list[host_index].port,
263 pointer_index - 1);
264 }
265
266 WATCHPOINT_ASSERT(sort_host_length);
267
268 if (is_ketama_weighted)
269 {
270 for (uint32_t x = 0; x < pointer_per_hash; x++)
271 {
272 value= ketama_server_hash(sort_host, sort_host_length, x);
273 ptr->continuum[continuum_index].index= host_index;
274 ptr->continuum[continuum_index++].value= value;
275 }
276 }
277 else
278 {
279 value= hashkit_digest(&ptr->distribution_hashkit, sort_host, sort_host_length);
280 ptr->continuum[continuum_index].index= host_index;
281 ptr->continuum[continuum_index++].value= value;
282 }
283 }
284 }
285
286 pointer_counter+= pointer_per_server;
287 }
288
289 WATCHPOINT_ASSERT(ptr);
290 WATCHPOINT_ASSERT(ptr->continuum);
291 WATCHPOINT_ASSERT(memcached_server_count(ptr) * MEMCACHED_POINTS_PER_SERVER <= MEMCACHED_CONTINUUM_SIZE);
292 ptr->continuum_points_counter= pointer_counter;
293 qsort(ptr->continuum, ptr->continuum_points_counter, sizeof(memcached_continuum_item_st), continuum_item_cmp);
294
295 #ifdef DEBUG
296 for (pointer_index= 0; memcached_server_count(ptr) && pointer_index < ((live_servers * MEMCACHED_POINTS_PER_SERVER) - 1); pointer_index++)
297 {
298 WATCHPOINT_ASSERT(ptr->continuum[pointer_index].value <= ptr->continuum[pointer_index + 1].value);
299 }
300 #endif
301
302 return MEMCACHED_SUCCESS;
303 }
304
305
306 memcached_return_t memcached_server_push(memcached_st *ptr, const memcached_server_list_st list)
307 {
308 uint32_t count;
309 memcached_server_st *new_host_list;
310
311 if (! list)
312 return MEMCACHED_SUCCESS;
313
314 count= memcached_server_list_count(list);
315 new_host_list= libmemcached_realloc(ptr, memcached_server_list(ptr),
316 sizeof(memcached_server_st) * (count + memcached_server_count(ptr)));
317
318 if (! new_host_list)
319 return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
320
321 memcached_server_list_set(ptr, new_host_list);
322
323 for (uint32_t x= 0; x < count; x++)
324 {
325 memcached_server_write_instance_st instance;
326
327 if ((ptr->flags.use_udp && list[x].type != MEMCACHED_CONNECTION_UDP)
328 || ((list[x].type == MEMCACHED_CONNECTION_UDP)
329 && ! (ptr->flags.use_udp)) )
330 return MEMCACHED_INVALID_HOST_PROTOCOL;
331
332 WATCHPOINT_ASSERT(list[x].hostname[0] != 0);
333
334 instance= memcached_server_instance_fetch(ptr, memcached_server_count(ptr));
335
336 /* TODO check return type */
337 (void)memcached_server_create_with(ptr, instance, list[x].hostname,
338 list[x].port, list[x].weight, list[x].type);
339 ptr->number_of_hosts++;
340 }
341
342 // Provides backwards compatibility with server list.
343 {
344 memcached_server_write_instance_st instance;
345 instance= memcached_server_instance_fetch(ptr, 0);
346 instance->number_of_hosts= memcached_server_count(ptr);
347 }
348
349 return run_distribution(ptr);
350 }
351
352 memcached_return_t memcached_server_add_unix_socket(memcached_st *ptr,
353 const char *filename)
354 {
355 return memcached_server_add_unix_socket_with_weight(ptr, filename, 0);
356 }
357
358 memcached_return_t memcached_server_add_unix_socket_with_weight(memcached_st *ptr,
359 const char *filename,
360 uint32_t weight)
361 {
362 if (! filename)
363 return MEMCACHED_FAILURE;
364
365 return server_add(ptr, filename, 0, weight, MEMCACHED_CONNECTION_UNIX_SOCKET);
366 }
367
368 memcached_return_t memcached_server_add_udp(memcached_st *ptr,
369 const char *hostname,
370 in_port_t port)
371 {
372 return memcached_server_add_udp_with_weight(ptr, hostname, port, 0);
373 }
374
375 memcached_return_t memcached_server_add_udp_with_weight(memcached_st *ptr,
376 const char *hostname,
377 in_port_t port,
378 uint32_t weight)
379 {
380 if (! port)
381 port= MEMCACHED_DEFAULT_PORT;
382
383 if (! hostname)
384 hostname= "localhost";
385
386 return server_add(ptr, hostname, port, weight, MEMCACHED_CONNECTION_UDP);
387 }
388
389 memcached_return_t memcached_server_add(memcached_st *ptr,
390 const char *hostname,
391 in_port_t port)
392 {
393 return memcached_server_add_with_weight(ptr, hostname, port, 0);
394 }
395
396 memcached_return_t memcached_server_add_with_weight(memcached_st *ptr,
397 const char *hostname,
398 in_port_t port,
399 uint32_t weight)
400 {
401 if (! port)
402 port= MEMCACHED_DEFAULT_PORT;
403
404 if (! hostname)
405 hostname= "localhost";
406
407 return server_add(ptr, hostname, port, weight, MEMCACHED_CONNECTION_TCP);
408 }
409
410 static memcached_return_t server_add(memcached_st *ptr, const char *hostname,
411 in_port_t port,
412 uint32_t weight,
413 memcached_connection_t type)
414 {
415 memcached_server_st *new_host_list;
416 memcached_server_write_instance_st instance;
417
418 if ( (ptr->flags.use_udp && type != MEMCACHED_CONNECTION_UDP)
419 || ( (type == MEMCACHED_CONNECTION_UDP) && (! ptr->flags.use_udp) ) )
420 return MEMCACHED_INVALID_HOST_PROTOCOL;
421
422 new_host_list= libmemcached_realloc(ptr, memcached_server_list(ptr),
423 sizeof(memcached_server_st) * (ptr->number_of_hosts + 1));
424
425 if (new_host_list == NULL)
426 return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
427
428 memcached_server_list_set(ptr, new_host_list);
429
430 /* TODO: Check return type */
431 instance= memcached_server_instance_fetch(ptr, memcached_server_count(ptr));
432 (void)memcached_server_create_with(ptr, instance, hostname, port, weight, type);
433 ptr->number_of_hosts++;
434
435 instance= memcached_server_instance_fetch(ptr, 0);
436 memcached_servers_set_count(instance, memcached_server_count(ptr));
437
438 return run_distribution(ptr);
439 }