git.m6w6.name Git - m6w6/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_instance_st *a= (memcached_server_instance_st *)p1;
  15   memcached_server_instance_st *b= (memcached_server_instance_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     memcached_server_instance_st *instance;
  32
  33     qsort(memcached_server_list(ptr), memcached_server_count(ptr), sizeof(memcached_server_instance_st), compare_servers);
  34     instance= memcached_server_instance_fetch(ptr, 0);
  35     instance->number_of_hosts= memcached_server_count(ptr);
  36   }
  37 }
  38
  39
  40 memcached_return_t run_distribution(memcached_st *ptr)
  41 {
  42   if (ptr->flags.use_sort_hosts)
  43     sort_hosts(ptr);
  44
  45   switch (ptr->distribution)
  46   {
  47   case MEMCACHED_DISTRIBUTION_CONSISTENT:
  48   case MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA:
  49   case MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA_SPY:
  50     return update_continuum(ptr);
  51   case MEMCACHED_DISTRIBUTION_MODULA:
  52     break;
  53   case MEMCACHED_DISTRIBUTION_RANDOM:
  54     srandom((uint32_t) time(NULL));
  55     break;
  56   case MEMCACHED_DISTRIBUTION_CONSISTENT_MAX:
  57   default:
  58     WATCHPOINT_ASSERT(0); /* We have added a distribution without extending the logic */
  59   }
  60
  61   ptr->last_disconnected_server = NULL;
  62
  63   return MEMCACHED_SUCCESS;
  64 }
  65
  66 static uint32_t ketama_server_hash(const char *key, unsigned int key_length, int alignment)
  67 {
  68   unsigned char results[16];
  69
  70   md5_signature((unsigned char*)key, key_length, results);
  71   return ((uint32_t) (results[3 + alignment * 4] & 0xFF) << 24)
  72     | ((uint32_t) (results[2 + alignment * 4] & 0xFF) << 16)
  73     | ((uint32_t) (results[1 + alignment * 4] & 0xFF) << 8)
  74     | (results[0 + alignment * 4] & 0xFF);
  75 }
  76
  77 static int continuum_item_cmp(const void *t1, const void *t2)
  78 {
  79   memcached_continuum_item_st *ct1= (memcached_continuum_item_st *)t1;
  80   memcached_continuum_item_st *ct2= (memcached_continuum_item_st *)t2;
  81
  82   /* Why 153? Hmmm... */
  83   WATCHPOINT_ASSERT(ct1->value != 153);
  84   if (ct1->value == ct2->value)
  85     return 0;
  86   else if (ct1->value > ct2->value)
  87     return 1;
  88   else
  89     return -1;
  90 }
  91
  92 static memcached_return_t update_continuum(memcached_st *ptr)
  93 {
  94   uint32_t host_index;
  95   uint32_t continuum_index= 0;
  96   uint32_t value;
  97   memcached_server_instance_st *list;
  98   uint32_t pointer_index;
  99   uint32_t pointer_counter= 0;
 100   uint32_t pointer_per_server= MEMCACHED_POINTS_PER_SERVER;
 101   uint32_t pointer_per_hash= 1;
 102   uint64_t total_weight= 0;
 103   uint64_t is_ketama_weighted= 0;
 104   uint64_t is_auto_ejecting= 0;
 105   uint32_t points_per_server= 0;
 106   uint32_t live_servers= 0;
 107   struct timeval now;
 108
 109   if (gettimeofday(&now, NULL) != 0)
 110   {
 111     ptr->cached_errno = errno;
 112     return MEMCACHED_ERRNO;
 113   }
 114
 115   list = memcached_server_list(ptr);
 116
 117   /* count live servers (those without a retry delay set) */
 118   is_auto_ejecting= memcached_behavior_get(ptr, MEMCACHED_BEHAVIOR_AUTO_EJECT_HOSTS);
 119   if (is_auto_ejecting)
 120   {
 121     live_servers= 0;
 122     ptr->next_distribution_rebuild= 0;
 123     for (host_index= 0; host_index < memcached_server_count(ptr); ++host_index)
 124     {
 125       if (list[host_index].next_retry <= now.tv_sec)
 126         live_servers++;
 127       else
 128       {
 129         if (ptr->next_distribution_rebuild == 0 || list[host_index].next_retry < ptr->next_distribution_rebuild)
 130           ptr->next_distribution_rebuild= list[host_index].next_retry;
 131       }
 132     }
 133   }
 134   else
 135   {
 136     live_servers= memcached_server_count(ptr);
 137   }
 138
 139   is_ketama_weighted= memcached_behavior_get(ptr, MEMCACHED_BEHAVIOR_KETAMA_WEIGHTED);
 140   points_per_server= (uint32_t) (is_ketama_weighted ? MEMCACHED_POINTS_PER_SERVER_KETAMA : MEMCACHED_POINTS_PER_SERVER);
 141
 142   if (live_servers == 0)
 143     return MEMCACHED_SUCCESS;
 144
 145   if (live_servers > ptr->continuum_count)
 146   {
 147     memcached_continuum_item_st *new_ptr;
 148
 149     new_ptr= libmemcached_realloc(ptr, ptr->continuum,
 150                                   sizeof(memcached_continuum_item_st) * (live_servers + MEMCACHED_CONTINUUM_ADDITION) * points_per_server);
 151
 152     if (new_ptr == 0)
 153       return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 154
 155     ptr->continuum= new_ptr;
 156     ptr->continuum_count= live_servers + MEMCACHED_CONTINUUM_ADDITION;
 157   }
 158
 159   if (is_ketama_weighted)
 160   {
 161     for (host_index = 0; host_index < memcached_server_count(ptr); ++host_index)
 162     {
 163       if (list[host_index].weight == 0)
 164       {
 165         list[host_index].weight = 1;
 166       }
 167       if (!is_auto_ejecting || list[host_index].next_retry <= now.tv_sec)
 168         total_weight += list[host_index].weight;
 169     }
 170   }
 171
 172   for (host_index = 0; host_index < memcached_server_count(ptr); ++host_index)
 173   {
 174     if (is_auto_ejecting && list[host_index].next_retry > now.tv_sec)
 175       continue;
 176
 177     if (is_ketama_weighted)
 178     {
 179         float pct = (float)list[host_index].weight / (float)total_weight;
 180         pointer_per_server= (uint32_t) ((floorf((float) (pct * MEMCACHED_POINTS_PER_SERVER_KETAMA / 4 * (float)live_servers + 0.0000000001))) * 4);
 181         pointer_per_hash= 4;
 182 #ifdef DEBUG
 183         printf("ketama_weighted:%s|%d|%llu|%u\n",
 184                list[host_index].hostname,
 185                list[host_index].port,
 186                (unsigned long long)list[host_index].weight,
 187                pointer_per_server);
 188 #endif
 189     }
 190
 191
 192     if (ptr->distribution == MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA_SPY)
 193     {
 194       for (pointer_index= 0;
 195            pointer_index < pointer_per_server / pointer_per_hash;
 196            pointer_index++)
 197       {
 198         char sort_host[MEMCACHED_MAX_HOST_SORT_LENGTH]= "";
 199         size_t sort_host_length;
 200
 201         // Spymemcached ketema key format is: hostname/ip:port-index
 202         // If hostname is not available then: /ip:port-index
 203         sort_host_length= (size_t) snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH,
 204                                             "/%s:%u-%u",
 205                                             list[host_index].hostname,
 206                                             (uint32_t)list[host_index].port,
 207                                             pointer_index);
 208 #ifdef DEBUG
 209         printf("update_continuum: key is %s\n", sort_host);
 210 #endif
 211
 212         WATCHPOINT_ASSERT(sort_host_length);
 213
 214         if (is_ketama_weighted)
 215         {
 216           unsigned int i;
 217           for (i = 0; i < pointer_per_hash; i++)
 218           {
 219              value= ketama_server_hash(sort_host, (uint32_t) sort_host_length, (int) i);
 220              ptr->continuum[continuum_index].index= host_index;
 221              ptr->continuum[continuum_index++].value= value;
 222           }
 223         }
 224         else
 225         {
 226           value= memcached_generate_hash_value(sort_host, sort_host_length, ptr->distribution_hash);
 227           ptr->continuum[continuum_index].index= host_index;
 228           ptr->continuum[continuum_index++].value= value;
 229         }
 230       }
 231     }
 232     else
 233     {
 234       for (pointer_index= 1;
 235            pointer_index <= pointer_per_server / pointer_per_hash;
 236            pointer_index++)
 237       {
 238         char sort_host[MEMCACHED_MAX_HOST_SORT_LENGTH]= "";
 239         size_t sort_host_length;
 240
 241         if (list[host_index].port == MEMCACHED_DEFAULT_PORT)
 242         {
 243           sort_host_length= (size_t) snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH,
 244                                               "%s-%u",
 245                                               list[host_index].hostname,
 246                                               pointer_index - 1);
 247         }
 248         else
 249         {
 250           sort_host_length= (size_t) snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH,
 251                                               "%s:%u-%u",
 252                                               list[host_index].hostname,
 253                                               (uint32_t)list[host_index].port,
 254                                               pointer_index - 1);
 255         }
 256
 257         WATCHPOINT_ASSERT(sort_host_length);
 258
 259         if (is_ketama_weighted)
 260         {
 261           unsigned int i;
 262           for (i = 0; i < pointer_per_hash; i++)
 263           {
 264              value= ketama_server_hash(sort_host, (uint32_t) sort_host_length, (int) i);
 265              ptr->continuum[continuum_index].index= host_index;
 266              ptr->continuum[continuum_index++].value= value;
 267           }
 268         }
 269         else
 270         {
 271           value= memcached_generate_hash_value(sort_host, sort_host_length, ptr->distribution_hash);
 272           ptr->continuum[continuum_index].index= host_index;
 273           ptr->continuum[continuum_index++].value= value;
 274         }
 275       }
 276     }
 277
 278     pointer_counter+= pointer_per_server;
 279   }
 280
 281   WATCHPOINT_ASSERT(ptr);
 282   WATCHPOINT_ASSERT(ptr->continuum);
 283   WATCHPOINT_ASSERT(memcached_server_count(ptr) * MEMCACHED_POINTS_PER_SERVER <= MEMCACHED_CONTINUUM_SIZE);
 284   ptr->continuum_points_counter= pointer_counter;
 285   qsort(ptr->continuum, ptr->continuum_points_counter, sizeof(memcached_continuum_item_st), continuum_item_cmp);
 286
 287 #ifdef DEBUG
 288   for (pointer_index= 0; memcached_server_count(ptr) && pointer_index < ((live_servers * MEMCACHED_POINTS_PER_SERVER) - 1); pointer_index++)
 289   {
 290     WATCHPOINT_ASSERT(ptr->continuum[pointer_index].value <= ptr->continuum[pointer_index + 1].value);
 291   }
 292 #endif
 293
 294   return MEMCACHED_SUCCESS;
 295 }
 296
 297
 298 memcached_return_t memcached_server_push(memcached_st *ptr, memcached_server_st *list)
 299 {
 300   uint32_t count;
 301   memcached_server_st *new_host_list;
 302
 303   if (! list)
 304     return MEMCACHED_SUCCESS;
 305
 306   count= memcached_servers_count(list);
 307   new_host_list= libmemcached_realloc(ptr, memcached_server_list(ptr),
 308                                       sizeof(memcached_server_instance_st) * (count + memcached_server_count(ptr)));
 309
 310   if (! new_host_list)
 311     return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 312
 313   memcached_server_list_set(ptr, new_host_list);
 314
 315   for (uint32_t x= 0; x < count; x++)
 316   {
 317     memcached_server_instance_st *instance;
 318
 319     if ((ptr->flags.use_udp && list[x].type != MEMCACHED_CONNECTION_UDP)
 320             || ((list[x].type == MEMCACHED_CONNECTION_UDP)
 321             && ! (ptr->flags.use_udp)) )
 322       return MEMCACHED_INVALID_HOST_PROTOCOL;
 323
 324     WATCHPOINT_ASSERT(list[x].hostname[0] != 0);
 325
 326     instance= memcached_server_instance_fetch(ptr, memcached_server_count(ptr));
 327
 328     /* TODO check return type */
 329     (void)memcached_server_create_with(ptr, instance, list[x].hostname,
 330                                        list[x].port, list[x].weight, list[x].type);
 331     ptr->number_of_hosts++;
 332   }
 333
 334   // Provides backwards compatibility with server list.
 335   {
 336     memcached_server_instance_st *instance;
 337     instance= memcached_server_instance_fetch(ptr, 0);
 338     instance->number_of_hosts= memcached_server_count(ptr);
 339   }
 340
 341   return run_distribution(ptr);
 342 }
 343
 344 memcached_return_t memcached_server_add_unix_socket(memcached_st *ptr,
 345                                                     const char *filename)
 346 {
 347   return memcached_server_add_unix_socket_with_weight(ptr, filename, 0);
 348 }
 349
 350 memcached_return_t memcached_server_add_unix_socket_with_weight(memcached_st *ptr,
 351                                                                 const char *filename,
 352                                                                 uint32_t weight)
 353 {
 354   if (! filename)
 355     return MEMCACHED_FAILURE;
 356
 357   return server_add(ptr, filename, 0, weight, MEMCACHED_CONNECTION_UNIX_SOCKET);
 358 }
 359
 360 memcached_return_t memcached_server_add_udp(memcached_st *ptr,
 361                                             const char *hostname,
 362                                             in_port_t port)
 363 {
 364   return memcached_server_add_udp_with_weight(ptr, hostname, port, 0);
 365 }
 366
 367 memcached_return_t memcached_server_add_udp_with_weight(memcached_st *ptr,
 368                                                         const char *hostname,
 369                                                         in_port_t port,
 370                                                         uint32_t weight)
 371 {
 372   if (! port)
 373     port= MEMCACHED_DEFAULT_PORT;
 374
 375   if (! hostname)
 376     hostname= "localhost";
 377
 378   return server_add(ptr, hostname, port, weight, MEMCACHED_CONNECTION_UDP);
 379 }
 380
 381 memcached_return_t memcached_server_add(memcached_st *ptr,
 382                                         const char *hostname,
 383                                         in_port_t port)
 384 {
 385   return memcached_server_add_with_weight(ptr, hostname, port, 0);
 386 }
 387
 388 memcached_return_t memcached_server_add_with_weight(memcached_st *ptr,
 389                                                     const char *hostname,
 390                                                     in_port_t port,
 391                                                     uint32_t weight)
 392 {
 393   if (! port)
 394     port= MEMCACHED_DEFAULT_PORT;
 395
 396   if (! hostname)
 397     hostname= "localhost";
 398
 399   return server_add(ptr, hostname, port, weight, MEMCACHED_CONNECTION_TCP);
 400 }
 401
 402 static memcached_return_t server_add(memcached_st *ptr, const char *hostname,
 403                                      in_port_t port,
 404                                      uint32_t weight,
 405                                      memcached_connection_t type)
 406 {
 407   memcached_server_instance_st *new_host_list;
 408   memcached_server_instance_st *instance;
 409
 410   if ( (ptr->flags.use_udp && type != MEMCACHED_CONNECTION_UDP)
 411       || ( (type == MEMCACHED_CONNECTION_UDP) && (! ptr->flags.use_udp) ) )
 412     return MEMCACHED_INVALID_HOST_PROTOCOL;
 413
 414   new_host_list= libmemcached_realloc(ptr, memcached_server_list(ptr),
 415                                       sizeof(memcached_server_instance_st) * (ptr->number_of_hosts + 1));
 416
 417   if (new_host_list == NULL)
 418     return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 419
 420   memcached_server_list_set(ptr, new_host_list);
 421
 422   /* TODO: Check return type */
 423   instance= memcached_server_instance_fetch(ptr, memcached_server_count(ptr));
 424   (void)memcached_server_create_with(ptr, instance, hostname, port, weight, type);
 425   ptr->number_of_hosts++;
 426
 427   instance= memcached_server_instance_fetch(ptr, 0);
 428   memcached_servers_set_count(instance, memcached_server_count(ptr));
 429
 430   return run_distribution(ptr);
 431 }
 432
 433 /**
 434   @todo allow lists to query themselves even if they lack a root
 435 */
 436 memcached_return_t memcached_server_remove(memcached_server_st *st_ptr)
 437 {
 438   uint32_t x, host_index;
 439   memcached_st *root= (memcached_st *)st_ptr->root;
 440   memcached_server_st *list;
 441
 442   if (root == NULL)
 443     return MEMCACHED_FAILURE;
 444
 445   list= memcached_server_list(root);
 446
 447   for (x= 0, host_index= 0; x < memcached_server_count(root); x++)
 448   {
 449     if (strncmp(list[x].hostname, st_ptr->hostname, MEMCACHED_MAX_HOST_LENGTH) != 0 || list[x].port != st_ptr->port)
 450     {
 451       if (host_index != x)
 452         memcpy(list+host_index, list+x, sizeof(memcached_server_st));
 453       host_index++;
 454     }
 455   }
 456   root->number_of_hosts= host_index;
 457
 458   if (st_ptr->address_info)
 459   {
 460     freeaddrinfo(st_ptr->address_info);
 461     st_ptr->address_info= NULL;
 462   }
 463   run_distribution(root);
 464
 465   return MEMCACHED_SUCCESS;
 466 }
 467
 468 memcached_server_st *memcached_server_list_append(memcached_server_st *ptr,
 469                                                   const char *hostname, in_port_t port,
 470                                                   memcached_return_t *error)
 471 {
 472   return memcached_server_list_append_with_weight(ptr, hostname, port, 0, error);
 473 }
 474
 475 memcached_server_st *memcached_server_list_append_with_weight(memcached_server_st *ptr,
 476                                                               const char *hostname, in_port_t port,
 477                                                               uint32_t weight,
 478                                                               memcached_return_t *error)
 479 {
 480   unsigned int count;
 481   memcached_server_instance_st *new_host_list;
 482
 483   if (hostname == NULL || error == NULL)
 484     return NULL;
 485
 486   if (! port)
 487     port= MEMCACHED_DEFAULT_PORT;
 488
 489   /* Increment count for hosts */
 490   count= 1;
 491   if (ptr != NULL)
 492   {
 493     count+= memcached_servers_count(ptr);
 494   }
 495
 496   new_host_list= (memcached_server_instance_st *)realloc(ptr, sizeof(memcached_server_instance_st) * count);
 497   if (!new_host_list)
 498   {
 499     *error= MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 500     return NULL;
 501   }
 502
 503   /* TODO: Check return type */
 504   memcached_server_create_with(NULL, &new_host_list[count-1], hostname, port, weight, MEMCACHED_CONNECTION_TCP);
 505
 506   /* Backwards compatibility hack */
 507   memcached_servers_set_count(new_host_list, count);
 508
 509   *error= MEMCACHED_SUCCESS;
 510   return new_host_list;
 511 }