git.m6w6.name Git - awesomized/libmemcached/blob - libmemcached/hosts.cc

   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
  21 static memcached_return_t update_continuum(memcached_st *ptr);
  22
  23 static int compare_servers(const void *p1, const void *p2)
  24 {
  25   int return_value;
  26   memcached_server_instance_st a= (memcached_server_instance_st)p1;
  27   memcached_server_instance_st b= (memcached_server_instance_st)p2;
  28
  29   return_value= strcmp(a->hostname, b->hostname);
  30
  31   if (return_value == 0)
  32   {
  33     return_value= (int) (a->port - b->port);
  34   }
  35
  36   return return_value;
  37 }
  38
  39 static void sort_hosts(memcached_st *ptr)
  40 {
  41   if (memcached_server_count(ptr))
  42   {
  43     memcached_server_write_instance_st instance;
  44
  45     qsort(memcached_server_list(ptr), memcached_server_count(ptr), sizeof(memcached_server_st), compare_servers);
  46     instance= memcached_server_instance_fetch(ptr, 0);
  47     instance->number_of_hosts= memcached_server_count(ptr);
  48   }
  49 }
  50
  51
  52 memcached_return_t run_distribution(memcached_st *ptr)
  53 {
  54   if (ptr->flags.use_sort_hosts)
  55     sort_hosts(ptr);
  56
  57   switch (ptr->distribution)
  58   {
  59   case MEMCACHED_DISTRIBUTION_CONSISTENT:
  60   case MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA:
  61   case MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA_SPY:
  62   case MEMCACHED_DISTRIBUTION_CONSISTENT_WEIGHTED:
  63     return update_continuum(ptr);
  64   case MEMCACHED_DISTRIBUTION_VIRTUAL_BUCKET:
  65   case MEMCACHED_DISTRIBUTION_MODULA:
  66     break;
  67   case MEMCACHED_DISTRIBUTION_RANDOM:
  68     srandom((uint32_t) time(NULL));
  69     break;
  70   case MEMCACHED_DISTRIBUTION_CONSISTENT_MAX:
  71   default:
  72     WATCHPOINT_ASSERT(0); /* We have added a distribution without extending the logic */
  73   }
  74
  75   return MEMCACHED_SUCCESS;
  76 }
  77
  78 static uint32_t ketama_server_hash(const char *key, size_t key_length, uint32_t alignment)
  79 {
  80   unsigned char results[16];
  81
  82   libhashkit_md5_signature((unsigned char*)key, key_length, results);
  83
  84   return ((uint32_t) (results[3 + alignment * 4] & 0xFF) << 24)
  85     | ((uint32_t) (results[2 + alignment * 4] & 0xFF) << 16)
  86     | ((uint32_t) (results[1 + alignment * 4] & 0xFF) << 8)
  87     | (results[0 + alignment * 4] & 0xFF);
  88 }
  89
  90 static int continuum_item_cmp(const void *t1, const void *t2)
  91 {
  92   memcached_continuum_item_st *ct1= (memcached_continuum_item_st *)t1;
  93   memcached_continuum_item_st *ct2= (memcached_continuum_item_st *)t2;
  94
  95   /* Why 153? Hmmm... */
  96   WATCHPOINT_ASSERT(ct1->value != 153);
  97   if (ct1->value == ct2->value)
  98     return 0;
  99   else if (ct1->value > ct2->value)
 100     return 1;
 101   else
 102     return -1;
 103 }
 104
 105 static memcached_return_t update_continuum(memcached_st *ptr)
 106 {
 107   uint32_t continuum_index= 0;
 108   memcached_server_st *list;
 109   uint32_t pointer_counter= 0;
 110   uint32_t pointer_per_server= MEMCACHED_POINTS_PER_SERVER;
 111   uint32_t pointer_per_hash= 1;
 112   uint32_t live_servers= 0;
 113   struct timeval now;
 114
 115   if (gettimeofday(&now, NULL) != 0)
 116   {
 117     memcached_set_errno(ptr, errno, NULL);
 118     return MEMCACHED_ERRNO;
 119   }
 120
 121   list= memcached_server_list(ptr);
 122
 123   /* count live servers (those without a retry delay set) */
 124   bool is_auto_ejecting= _is_auto_eject_host(ptr);
 125   if (is_auto_ejecting)
 126   {
 127     live_servers= 0;
 128     ptr->ketama.next_distribution_rebuild= 0;
 129     for (uint32_t host_index= 0; host_index < memcached_server_count(ptr); ++host_index)
 130     {
 131       if (list[host_index].next_retry <= now.tv_sec)
 132         live_servers++;
 133       else
 134       {
 135         if (ptr->ketama.next_distribution_rebuild == 0 || list[host_index].next_retry < ptr->ketama.next_distribution_rebuild)
 136           ptr->ketama.next_distribution_rebuild= list[host_index].next_retry;
 137       }
 138     }
 139   }
 140   else
 141   {
 142     live_servers= memcached_server_count(ptr);
 143   }
 144
 145   uint64_t is_ketama_weighted= memcached_behavior_get(ptr, MEMCACHED_BEHAVIOR_KETAMA_WEIGHTED);
 146   uint32_t points_per_server= (uint32_t) (is_ketama_weighted ? MEMCACHED_POINTS_PER_SERVER_KETAMA : MEMCACHED_POINTS_PER_SERVER);
 147
 148   if (live_servers == 0)
 149     return MEMCACHED_SUCCESS;
 150
 151   if (live_servers > ptr->ketama.continuum_count)
 152   {
 153     memcached_continuum_item_st *new_ptr;
 154
 155     new_ptr= static_cast<memcached_continuum_item_st*>(libmemcached_realloc(ptr, ptr->ketama.continuum,
 156                                                                             sizeof(memcached_continuum_item_st) * (live_servers + MEMCACHED_CONTINUUM_ADDITION) * points_per_server));
 157
 158     if (new_ptr == 0)
 159       return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 160
 161     ptr->ketama.continuum= new_ptr;
 162     ptr->ketama.continuum_count= live_servers + MEMCACHED_CONTINUUM_ADDITION;
 163   }
 164
 165   uint64_t total_weight= 0;
 166   if (is_ketama_weighted)
 167   {
 168     for (uint32_t host_index = 0; host_index < memcached_server_count(ptr); ++host_index)
 169     {
 170       if (! is_auto_ejecting || list[host_index].next_retry <= now.tv_sec)
 171       {
 172         total_weight += list[host_index].weight;
 173       }
 174     }
 175   }
 176
 177   for (uint32_t host_index= 0; host_index < memcached_server_count(ptr); ++host_index)
 178   {
 179     if (is_auto_ejecting && list[host_index].next_retry > now.tv_sec)
 180       continue;
 181
 182     if (is_ketama_weighted)
 183     {
 184         float pct = (float)list[host_index].weight / (float)total_weight;
 185         pointer_per_server= (uint32_t) ((floorf((float) (pct * MEMCACHED_POINTS_PER_SERVER_KETAMA / 4 * (float)live_servers + 0.0000000001))) * 4);
 186         pointer_per_hash= 4;
 187 #ifdef DEBUG
 188         printf("ketama_weighted:%s|%d|%llu|%u\n",
 189                list[host_index].hostname,
 190                list[host_index].port,
 191                (unsigned long long)list[host_index].weight,
 192                pointer_per_server);
 193 #endif
 194     }
 195
 196
 197     if (ptr->distribution == MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA_SPY)
 198     {
 199       for (uint32_t pointer_index= 0;
 200            pointer_index < pointer_per_server / pointer_per_hash;
 201            pointer_index++)
 202       {
 203         char sort_host[MEMCACHED_MAX_HOST_SORT_LENGTH]= "";
 204         int sort_host_length;
 205
 206         // Spymemcached ketema key format is: hostname/ip:port-index
 207         // If hostname is not available then: /ip:port-index
 208         sort_host_length= snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH,
 209                                    "/%s:%u-%u",
 210                                    list[host_index].hostname,
 211                                    (uint32_t)list[host_index].port,
 212                                    pointer_index);
 213
 214         if (sort_host_length >= MEMCACHED_MAX_HOST_SORT_LENGTH || sort_host_length < 0)
 215         {
 216           return MEMCACHED_FAILURE;
 217         }
 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             uint32_t value= ketama_server_hash(sort_host, (size_t)sort_host_length, x);
 229              ptr->ketama.continuum[continuum_index].index= host_index;
 230              ptr->ketama.continuum[continuum_index++].value= value;
 231           }
 232         }
 233         else
 234         {
 235           uint32_t value= hashkit_digest(&ptr->distribution_hashkit, sort_host, (size_t)sort_host_length);
 236           ptr->ketama.continuum[continuum_index].index= host_index;
 237           ptr->ketama.continuum[continuum_index++].value= value;
 238         }
 239       }
 240     }
 241     else
 242     {
 243       for (uint32_t 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         int sort_host_length;
 249
 250         if (list[host_index].port == MEMCACHED_DEFAULT_PORT)
 251         {
 252           sort_host_length= 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= 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         if (sort_host_length >= MEMCACHED_MAX_HOST_SORT_LENGTH || sort_host_length < 0)
 267         {
 268           return MEMCACHED_FAILURE;
 269         }
 270
 271         WATCHPOINT_ASSERT(sort_host_length);
 272
 273         if (is_ketama_weighted)
 274         {
 275           for (uint32_t x = 0; x < pointer_per_hash; x++)
 276           {
 277              uint32_t value= ketama_server_hash(sort_host, (size_t)sort_host_length, x);
 278              ptr->ketama.continuum[continuum_index].index= host_index;
 279              ptr->ketama.continuum[continuum_index++].value= value;
 280           }
 281         }
 282         else
 283         {
 284           uint32_t value= hashkit_digest(&ptr->distribution_hashkit, sort_host, (size_t)sort_host_length);
 285           ptr->ketama.continuum[continuum_index].index= host_index;
 286           ptr->ketama.continuum[continuum_index++].value= value;
 287         }
 288       }
 289     }
 290
 291     pointer_counter+= pointer_per_server;
 292   }
 293
 294   WATCHPOINT_ASSERT(ptr);
 295   WATCHPOINT_ASSERT(ptr->continuum);
 296   WATCHPOINT_ASSERT(memcached_server_count(ptr) * MEMCACHED_POINTS_PER_SERVER <= MEMCACHED_CONTINUUM_SIZE);
 297   ptr->ketama.continuum_points_counter= pointer_counter;
 298   qsort(ptr->ketama.continuum, ptr->ketama.continuum_points_counter, sizeof(memcached_continuum_item_st), continuum_item_cmp);
 299
 300 #ifdef DEBUG
 301   for (uint32_t pointer_index= 0; memcached_server_count(ptr) && pointer_index < ((live_servers * MEMCACHED_POINTS_PER_SERVER) - 1); pointer_index++)
 302   {
 303     WATCHPOINT_ASSERT(ptr->continuum[pointer_index].value <= ptr->continuum[pointer_index + 1].value);
 304   }
 305 #endif
 306
 307   return MEMCACHED_SUCCESS;
 308 }
 309
 310
 311 memcached_return_t memcached_server_push(memcached_st *ptr, const memcached_server_list_st list)
 312 {
 313   if (not list)
 314     return MEMCACHED_SUCCESS;
 315
 316   uint32_t count= memcached_server_list_count(list);
 317
 318   memcached_server_st *new_host_list;
 319   new_host_list= static_cast<memcached_server_st*>(libmemcached_realloc(ptr, memcached_server_list(ptr),
 320                                                                         sizeof(memcached_server_st) * (count + memcached_server_count(ptr))));
 321
 322   if (not new_host_list)
 323     return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 324
 325   memcached_server_list_set(ptr, new_host_list);
 326
 327   for (uint32_t x= 0; x < count; x++)
 328   {
 329     memcached_server_write_instance_st instance;
 330
 331     if ((ptr->flags.use_udp && list[x].type != MEMCACHED_CONNECTION_UDP)
 332             || ((list[x].type == MEMCACHED_CONNECTION_UDP)
 333             && ! (ptr->flags.use_udp)) )
 334     {
 335       return MEMCACHED_INVALID_HOST_PROTOCOL;
 336     }
 337
 338     WATCHPOINT_ASSERT(list[x].hostname[0] != 0);
 339
 340     instance= memcached_server_instance_fetch(ptr, memcached_server_count(ptr));
 341     WATCHPOINT_ASSERT(instance);
 342
 343     /* TODO check return type */
 344     instance= memcached_server_create_with(ptr, instance, list[x].hostname,
 345                                            list[x].port, list[x].weight, list[x].type);
 346     if (! instance)
 347     {
 348       return memcached_set_error(ptr, MEMCACHED_MEMORY_ALLOCATION_FAILURE, NULL);
 349     }
 350     ptr->number_of_hosts++;
 351   }
 352
 353   // Provides backwards compatibility with server list.
 354   {
 355     memcached_server_write_instance_st instance;
 356     instance= memcached_server_instance_fetch(ptr, 0);
 357     instance->number_of_hosts= memcached_server_count(ptr);
 358   }
 359
 360   return run_distribution(ptr);
 361 }
 362
 363 memcached_return_t memcached_server_add_unix_socket(memcached_st *ptr,
 364                                                     const char *filename)
 365 {
 366   return memcached_server_add_unix_socket_with_weight(ptr, filename, 0);
 367 }
 368
 369 memcached_return_t memcached_server_add_unix_socket_with_weight(memcached_st *ptr,
 370                                                                 const char *filename,
 371                                                                 uint32_t weight)
 372 {
 373   if (! filename)
 374     return MEMCACHED_FAILURE;
 375
 376   return server_add(ptr, filename, 0, weight, MEMCACHED_CONNECTION_UNIX_SOCKET);
 377 }
 378
 379 memcached_return_t memcached_server_add_udp(memcached_st *ptr,
 380                                             const char *hostname,
 381                                             in_port_t port)
 382 {
 383   return memcached_server_add_udp_with_weight(ptr, hostname, port, 0);
 384 }
 385
 386 memcached_return_t memcached_server_add_udp_with_weight(memcached_st *ptr,
 387                                                         const char *hostname,
 388                                                         in_port_t port,
 389                                                         uint32_t weight)
 390 {
 391   if (! port)
 392     port= MEMCACHED_DEFAULT_PORT;
 393
 394   if (! hostname)
 395     hostname= "localhost";
 396
 397   return server_add(ptr, hostname, port, weight, MEMCACHED_CONNECTION_UDP);
 398 }
 399
 400 memcached_return_t memcached_server_add(memcached_st *ptr,
 401                                         const char *hostname,
 402                                         in_port_t port)
 403 {
 404   return memcached_server_add_with_weight(ptr, hostname, port, 0);
 405 }
 406
 407 memcached_return_t memcached_server_add_with_weight(memcached_st *ptr,
 408                                                     const char *hostname,
 409                                                     in_port_t port,
 410                                                     uint32_t weight)
 411 {
 412   if (! port)
 413     port= MEMCACHED_DEFAULT_PORT;
 414
 415   if (! hostname)
 416     hostname= "localhost";
 417
 418   return server_add(ptr, hostname, port, weight, MEMCACHED_CONNECTION_TCP);
 419 }
 420
 421 static memcached_return_t server_add(memcached_st *ptr, const char *hostname,
 422                                      in_port_t port,
 423                                      uint32_t weight,
 424                                      memcached_connection_t type)
 425 {
 426   memcached_server_st *new_host_list;
 427   memcached_server_write_instance_st instance;
 428
 429   if ( (ptr->flags.use_udp && type != MEMCACHED_CONNECTION_UDP)
 430       || ( (type == MEMCACHED_CONNECTION_UDP) && (! ptr->flags.use_udp) ) )
 431     return MEMCACHED_INVALID_HOST_PROTOCOL;
 432
 433   new_host_list= static_cast<memcached_server_st*>(libmemcached_realloc(ptr, memcached_server_list(ptr),
 434                                                                         sizeof(memcached_server_st) * (ptr->number_of_hosts + 1)));
 435
 436   if (new_host_list == NULL)
 437     return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 438
 439   memcached_server_list_set(ptr, new_host_list);
 440
 441   /* TODO: Check return type */
 442   instance= memcached_server_instance_fetch(ptr, memcached_server_count(ptr));
 443   (void)memcached_server_create_with(ptr, instance, hostname, port, weight, type);
 444   ptr->number_of_hosts++;
 445
 446   instance= memcached_server_instance_fetch(ptr, 0);
 447   memcached_servers_set_count(instance, memcached_server_count(ptr));
 448
 449   return run_distribution(ptr);
 450 }