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

   1 #include "common.h"
   2 #include <math.h>
   3
   4 /* Protoypes (static) */
   5 static memcached_return_t server_add(memcached_st *ptr, const char *hostname,
   6                                      in_port_t port,
   7                                      uint32_t weight,
   8                                      memcached_connection_t type);
   9 static memcached_return_t update_continuum(memcached_st *ptr);
  10
  11 static int compare_servers(const void *p1, const void *p2)
  12 {
  13   int return_value;
  14   memcached_server_st *a= (memcached_server_st *)p1;
  15   memcached_server_st *b= (memcached_server_st *)p2;
  16
  17   return_value= strcmp(a->hostname, b->hostname);
  18
  19   if (return_value == 0)
  20   {
  21     return_value= (int) (a->port - b->port);
  22   }
  23
  24   return return_value;
  25 }
  26
  27 static void sort_hosts(memcached_st *ptr)
  28 {
  29   if (memcached_server_count(ptr))
  30   {
  31     qsort(ptr->hosts, memcached_server_count(ptr), sizeof(memcached_server_st), compare_servers);
  32     ptr->hosts[0].number_of_hosts= memcached_server_count(ptr);
  33   }
  34 }
  35
  36
  37 memcached_return_t run_distribution(memcached_st *ptr)
  38 {
  39   if (ptr->flags.use_sort_hosts)
  40     sort_hosts(ptr);
  41
  42   switch (ptr->distribution)
  43   {
  44   case MEMCACHED_DISTRIBUTION_CONSISTENT:
  45   case MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA:
  46   case MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA_SPY:
  47     return update_continuum(ptr);
  48   case MEMCACHED_DISTRIBUTION_MODULA:
  49     break;
  50   case MEMCACHED_DISTRIBUTION_RANDOM:
  51     srandom((uint32_t) time(NULL));
  52     break;
  53   case MEMCACHED_DISTRIBUTION_CONSISTENT_MAX:
  54   default:
  55     WATCHPOINT_ASSERT(0); /* We have added a distribution without extending the logic */
  56   }
  57
  58   ptr->last_disconnected_server = NULL;
  59
  60   return MEMCACHED_SUCCESS;
  61 }
  62
  63 static uint32_t ketama_server_hash(const char *key, unsigned int key_length, int alignment)
  64 {
  65   unsigned char results[16];
  66
  67   md5_signature((unsigned char*)key, key_length, results);
  68   return ((uint32_t) (results[3 + alignment * 4] & 0xFF) << 24)
  69     | ((uint32_t) (results[2 + alignment * 4] & 0xFF) << 16)
  70     | ((uint32_t) (results[1 + alignment * 4] & 0xFF) << 8)
  71     | (results[0 + alignment * 4] & 0xFF);
  72 }
  73
  74 static int continuum_item_cmp(const void *t1, const void *t2)
  75 {
  76   memcached_continuum_item_st *ct1= (memcached_continuum_item_st *)t1;
  77   memcached_continuum_item_st *ct2= (memcached_continuum_item_st *)t2;
  78
  79   /* Why 153? Hmmm... */
  80   WATCHPOINT_ASSERT(ct1->value != 153);
  81   if (ct1->value == ct2->value)
  82     return 0;
  83   else if (ct1->value > ct2->value)
  84     return 1;
  85   else
  86     return -1;
  87 }
  88
  89 static memcached_return_t update_continuum(memcached_st *ptr)
  90 {
  91   uint32_t host_index;
  92   uint32_t continuum_index= 0;
  93   uint32_t value;
  94   memcached_server_st *list;
  95   uint32_t pointer_index;
  96   uint32_t pointer_counter= 0;
  97   uint32_t pointer_per_server= MEMCACHED_POINTS_PER_SERVER;
  98   uint32_t pointer_per_hash= 1;
  99   uint64_t total_weight= 0;
 100   uint64_t is_ketama_weighted= 0;
 101   uint64_t is_auto_ejecting= 0;
 102   uint32_t points_per_server= 0;
 103   uint32_t live_servers= 0;
 104   struct timeval now;
 105
 106   if (gettimeofday(&now, NULL) != 0)
 107   {
 108     ptr->cached_errno = errno;
 109     return MEMCACHED_ERRNO;
 110   }
 111
 112   list = ptr->hosts;
 113
 114   /* count live servers (those without a retry delay set) */
 115   is_auto_ejecting= memcached_behavior_get(ptr, MEMCACHED_BEHAVIOR_AUTO_EJECT_HOSTS);
 116   if (is_auto_ejecting)
 117   {
 118     live_servers= 0;
 119     ptr->next_distribution_rebuild= 0;
 120     for (host_index= 0; host_index < memcached_server_count(ptr); ++host_index)
 121     {
 122       if (list[host_index].next_retry <= now.tv_sec)
 123         live_servers++;
 124       else
 125       {
 126         if (ptr->next_distribution_rebuild == 0 || list[host_index].next_retry < ptr->next_distribution_rebuild)
 127           ptr->next_distribution_rebuild= list[host_index].next_retry;
 128       }
 129     }
 130   }
 131   else
 132     live_servers= memcached_server_count(ptr);
 133
 134   is_ketama_weighted= memcached_behavior_get(ptr, MEMCACHED_BEHAVIOR_KETAMA_WEIGHTED);
 135   points_per_server= (uint32_t) (is_ketama_weighted ? MEMCACHED_POINTS_PER_SERVER_KETAMA : MEMCACHED_POINTS_PER_SERVER);
 136
 137   if (live_servers == 0)
 138     return MEMCACHED_SUCCESS;
 139
 140   if (live_servers > ptr->continuum_count)
 141   {
 142     memcached_continuum_item_st *new_ptr;
 143
 144     new_ptr= ptr->call_realloc(ptr, ptr->continuum,
 145                                sizeof(memcached_continuum_item_st) * (live_servers + MEMCACHED_CONTINUUM_ADDITION) * points_per_server);
 146
 147     if (new_ptr == 0)
 148       return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 149
 150     ptr->continuum= new_ptr;
 151     ptr->continuum_count= live_servers + MEMCACHED_CONTINUUM_ADDITION;
 152   }
 153
 154   if (is_ketama_weighted)
 155   {
 156     for (host_index = 0; host_index < memcached_server_count(ptr); ++host_index)
 157     {
 158       if (list[host_index].weight == 0)
 159       {
 160         list[host_index].weight = 1;
 161       }
 162       if (!is_auto_ejecting || list[host_index].next_retry <= now.tv_sec)
 163         total_weight += list[host_index].weight;
 164     }
 165   }
 166
 167   for (host_index = 0; host_index < memcached_server_count(ptr); ++host_index)
 168   {
 169     if (is_auto_ejecting && list[host_index].next_retry > now.tv_sec)
 170       continue;
 171
 172     if (is_ketama_weighted)
 173     {
 174         float pct = (float)list[host_index].weight / (float)total_weight;
 175         pointer_per_server= (uint32_t) ((floorf((float) (pct * MEMCACHED_POINTS_PER_SERVER_KETAMA / 4 * (float)live_servers + 0.0000000001))) * 4);
 176         pointer_per_hash= 4;
 177 #ifdef DEBUG
 178         printf("ketama_weighted:%s|%d|%llu|%u\n",
 179                list[host_index].hostname,
 180                list[host_index].port,
 181                (unsigned long long)list[host_index].weight,
 182                pointer_per_server);
 183 #endif
 184     }
 185
 186
 187     if (ptr->distribution == MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA_SPY)
 188     {
 189       for (pointer_index= 0;
 190            pointer_index < pointer_per_server / pointer_per_hash;
 191            pointer_index++)
 192       {
 193         char sort_host[MEMCACHED_MAX_HOST_SORT_LENGTH]= "";
 194         size_t sort_host_length;
 195
 196         // Spymemcached ketema key format is: hostname/ip:port-index
 197         // If hostname is not available then: /ip:port-index
 198         sort_host_length= (size_t) snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH,
 199                                             "/%s:%u-%u",
 200                                             list[host_index].hostname,
 201                                             (uint32_t)list[host_index].port,
 202                                             pointer_index);
 203 #ifdef DEBUG
 204         printf("update_continuum: key is %s\n", sort_host);
 205 #endif
 206
 207         WATCHPOINT_ASSERT(sort_host_length);
 208
 209         if (is_ketama_weighted)
 210         {
 211           unsigned int i;
 212           for (i = 0; i < pointer_per_hash; i++)
 213           {
 214              value= ketama_server_hash(sort_host, (uint32_t) sort_host_length, (int) i);
 215              ptr->continuum[continuum_index].index= host_index;
 216              ptr->continuum[continuum_index++].value= value;
 217           }
 218         }
 219         else
 220         {
 221           value= memcached_generate_hash_value(sort_host, sort_host_length, ptr->distribution_hash);
 222           ptr->continuum[continuum_index].index= host_index;
 223           ptr->continuum[continuum_index++].value= value;
 224         }
 225       }
 226     }
 227     else
 228     {
 229       for (pointer_index= 1;
 230            pointer_index <= pointer_per_server / pointer_per_hash;
 231            pointer_index++)
 232       {
 233         char sort_host[MEMCACHED_MAX_HOST_SORT_LENGTH]= "";
 234         size_t sort_host_length;
 235
 236         if (list[host_index].port == MEMCACHED_DEFAULT_PORT)
 237         {
 238           sort_host_length= (size_t) snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH,
 239                                               "%s-%u",
 240                                               list[host_index].hostname,
 241                                               pointer_index - 1);
 242         }
 243         else
 244         {
 245           sort_host_length= (size_t) snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH,
 246                                               "%s:%u-%u",
 247                                               list[host_index].hostname,
 248                                               (uint32_t)list[host_index].port,
 249                                               pointer_index - 1);
 250         }
 251
 252         WATCHPOINT_ASSERT(sort_host_length);
 253
 254         if (is_ketama_weighted)
 255         {
 256           unsigned int i;
 257           for (i = 0; i < pointer_per_hash; i++)
 258           {
 259              value= ketama_server_hash(sort_host, (uint32_t) sort_host_length, (int) i);
 260              ptr->continuum[continuum_index].index= host_index;
 261              ptr->continuum[continuum_index++].value= value;
 262           }
 263         }
 264         else
 265         {
 266           value= memcached_generate_hash_value(sort_host, sort_host_length, ptr->distribution_hash);
 267           ptr->continuum[continuum_index].index= host_index;
 268           ptr->continuum[continuum_index++].value= value;
 269         }
 270       }
 271     }
 272
 273     pointer_counter+= pointer_per_server;
 274   }
 275
 276   WATCHPOINT_ASSERT(ptr);
 277   WATCHPOINT_ASSERT(ptr->continuum);
 278   WATCHPOINT_ASSERT(memcached_server_count(ptr) * MEMCACHED_POINTS_PER_SERVER <= MEMCACHED_CONTINUUM_SIZE);
 279   ptr->continuum_points_counter= pointer_counter;
 280   qsort(ptr->continuum, ptr->continuum_points_counter, sizeof(memcached_continuum_item_st), continuum_item_cmp);
 281
 282 #ifdef DEBUG
 283   for (pointer_index= 0; memcached_server_count(ptr) && pointer_index < ((live_servers * MEMCACHED_POINTS_PER_SERVER) - 1); pointer_index++)
 284   {
 285     WATCHPOINT_ASSERT(ptr->continuum[pointer_index].value <= ptr->continuum[pointer_index + 1].value);
 286   }
 287 #endif
 288
 289   return MEMCACHED_SUCCESS;
 290 }
 291
 292
 293 memcached_return_t memcached_server_push(memcached_st *ptr, memcached_server_st *list)
 294 {
 295   unsigned int x;
 296   uint16_t count;
 297   memcached_server_st *new_host_list;
 298
 299   if (!list)
 300     return MEMCACHED_SUCCESS;
 301
 302   count= memcached_servers_count(list);
 303   new_host_list= ptr->call_realloc(ptr, ptr->hosts,
 304                                    sizeof(memcached_server_st) * (count + memcached_server_count(ptr)));
 305
 306   if (! new_host_list)
 307     return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 308
 309   ptr->hosts= new_host_list;
 310
 311   for (x= 0; x < count; x++)
 312   {
 313     if ((ptr->flags.use_udp && list[x].type != MEMCACHED_CONNECTION_UDP)
 314             || ((list[x].type == MEMCACHED_CONNECTION_UDP)
 315             && ! (ptr->flags.use_udp)) )
 316       return MEMCACHED_INVALID_HOST_PROTOCOL;
 317
 318     WATCHPOINT_ASSERT(list[x].hostname[0] != 0);
 319     memcached_server_create(ptr, &ptr->hosts[memcached_server_count(ptr)]);
 320     /* TODO check return type */
 321     (void)memcached_server_create_with(ptr, &ptr->hosts[memcached_server_count(ptr)], list[x].hostname,
 322                                        list[x].port, list[x].weight, list[x].type);
 323     ptr->number_of_hosts++;
 324   }
 325   ptr->hosts[0].number_of_hosts= memcached_server_count(ptr);
 326
 327   return run_distribution(ptr);
 328 }
 329
 330 memcached_return_t memcached_server_add_unix_socket(memcached_st *ptr,
 331                                                     const char *filename)
 332 {
 333   return memcached_server_add_unix_socket_with_weight(ptr, filename, 0);
 334 }
 335
 336 memcached_return_t memcached_server_add_unix_socket_with_weight(memcached_st *ptr,
 337                                                                 const char *filename,
 338                                                                 uint32_t weight)
 339 {
 340   if (!filename)
 341     return MEMCACHED_FAILURE;
 342
 343   return server_add(ptr, filename, 0, weight, MEMCACHED_CONNECTION_UNIX_SOCKET);
 344 }
 345
 346 memcached_return_t memcached_server_add_udp(memcached_st *ptr,
 347                                             const char *hostname,
 348                                             in_port_t port)
 349 {
 350   return memcached_server_add_udp_with_weight(ptr, hostname, port, 0);
 351 }
 352
 353 memcached_return_t memcached_server_add_udp_with_weight(memcached_st *ptr,
 354                                                         const char *hostname,
 355                                                         in_port_t port,
 356                                                         uint32_t weight)
 357 {
 358   if (!port)
 359     port= MEMCACHED_DEFAULT_PORT;
 360
 361   if (!hostname)
 362     hostname= "localhost";
 363
 364   return server_add(ptr, hostname, port, weight, MEMCACHED_CONNECTION_UDP);
 365 }
 366
 367 memcached_return_t memcached_server_add(memcached_st *ptr,
 368                                         const char *hostname,
 369                                         in_port_t port)
 370 {
 371   return memcached_server_add_with_weight(ptr, hostname, port, 0);
 372 }
 373
 374 memcached_return_t memcached_server_add_with_weight(memcached_st *ptr,
 375                                                     const char *hostname,
 376                                                     in_port_t port,
 377                                                     uint32_t weight)
 378 {
 379   if (!port)
 380     port= MEMCACHED_DEFAULT_PORT;
 381
 382   if (!hostname)
 383     hostname= "localhost";
 384
 385   return server_add(ptr, hostname, port, weight, MEMCACHED_CONNECTION_TCP);
 386 }
 387
 388 static memcached_return_t server_add(memcached_st *ptr, const char *hostname,
 389                                      in_port_t port,
 390                                      uint32_t weight,
 391                                      memcached_connection_t type)
 392 {
 393   memcached_server_st *new_host_list;
 394
 395   if ( (ptr->flags.use_udp && type != MEMCACHED_CONNECTION_UDP)
 396       || ( (type == MEMCACHED_CONNECTION_UDP) && (! ptr->flags.use_udp) ) )
 397     return MEMCACHED_INVALID_HOST_PROTOCOL;
 398
 399   new_host_list= ptr->call_realloc(ptr, ptr->hosts,
 400                                    sizeof(memcached_server_st) * (ptr->number_of_hosts + 1));
 401
 402   if (new_host_list == NULL)
 403     return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 404
 405   ptr->hosts= new_host_list;
 406
 407   /* TODO: Check return type */
 408   (void)memcached_server_create_with(ptr, &ptr->hosts[memcached_server_count(ptr)], hostname, port, weight, type);
 409   ptr->number_of_hosts++;
 410
 411   memcached_servers_set_count(&ptr->hosts[0], memcached_server_count(ptr));
 412
 413   return run_distribution(ptr);
 414 }
 415
 416 memcached_return_t memcached_server_remove(memcached_server_st *st_ptr)
 417 {
 418   uint32_t x, host_index;
 419   memcached_st *ptr= st_ptr->root;
 420   memcached_server_st *list= ptr->hosts;
 421
 422   for (x= 0, host_index= 0; x < memcached_server_count(ptr); x++)
 423   {
 424     if (strncmp(list[x].hostname, st_ptr->hostname, MEMCACHED_MAX_HOST_LENGTH) != 0 || list[x].port != st_ptr->port)
 425     {
 426       if (host_index != x)
 427         memcpy(list+host_index, list+x, sizeof(memcached_server_st));
 428       host_index++;
 429     }
 430   }
 431   ptr->number_of_hosts= host_index;
 432
 433   if (st_ptr->address_info)
 434   {
 435     freeaddrinfo(st_ptr->address_info);
 436     st_ptr->address_info= NULL;
 437   }
 438   run_distribution(ptr);
 439
 440   return MEMCACHED_SUCCESS;
 441 }
 442
 443 memcached_server_st *memcached_server_list_append(memcached_server_st *ptr,
 444                                                   const char *hostname, in_port_t port,
 445                                                   memcached_return_t *error)
 446 {
 447   return memcached_server_list_append_with_weight(ptr, hostname, port, 0, error);
 448 }
 449
 450 memcached_server_st *memcached_server_list_append_with_weight(memcached_server_st *ptr,
 451                                                               const char *hostname, in_port_t port,
 452                                                               uint32_t weight,
 453                                                               memcached_return_t *error)
 454 {
 455   unsigned int count;
 456   memcached_server_st *new_host_list;
 457
 458   if (hostname == NULL || error == NULL)
 459     return NULL;
 460
 461   if (!port)
 462     port= MEMCACHED_DEFAULT_PORT;
 463
 464   /* Increment count for hosts */
 465   count= 1;
 466   if (ptr != NULL)
 467   {
 468     count+= memcached_servers_count(ptr);
 469   }
 470
 471   new_host_list= (memcached_server_st *)realloc(ptr, sizeof(memcached_server_st) * count);
 472   if (!new_host_list)
 473   {
 474     *error= MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 475     return NULL;
 476   }
 477
 478   /* TODO: Check return type */
 479   memcached_server_create_with(NULL, &new_host_list[count-1], hostname, port, weight, MEMCACHED_CONNECTION_TCP);
 480
 481   /* Backwards compatibility hack */
 482   memcached_servers_set_count(new_host_list, count);
 483
 484   *error= MEMCACHED_SUCCESS;
 485   return new_host_list;
 486 }