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, uint32_t alignment)
  67 {
  68   unsigned char results[16];
  69
  70   libhashkit_md5_signature((unsigned char*)key, key_length, results);
  71
  72   return ((uint32_t) (results[3 + alignment * 4] & 0xFF) << 24)
  73     | ((uint32_t) (results[2 + alignment * 4] & 0xFF) << 16)
  74     | ((uint32_t) (results[1 + alignment * 4] & 0xFF) << 8)
  75     | (results[0 + alignment * 4] & 0xFF);
  76 }
  77
  78 static int continuum_item_cmp(const void *t1, const void *t2)
  79 {
  80   memcached_continuum_item_st *ct1= (memcached_continuum_item_st *)t1;
  81   memcached_continuum_item_st *ct2= (memcached_continuum_item_st *)t2;
  82
  83   /* Why 153? Hmmm... */
  84   WATCHPOINT_ASSERT(ct1->value != 153);
  85   if (ct1->value == ct2->value)
  86     return 0;
  87   else if (ct1->value > ct2->value)
  88     return 1;
  89   else
  90     return -1;
  91 }
  92
  93 static memcached_return_t update_continuum(memcached_st *ptr)
  94 {
  95   uint32_t host_index;
  96   uint32_t continuum_index= 0;
  97   uint32_t value;
  98   memcached_server_instance_st *list;
  99   uint32_t pointer_index;
 100   uint32_t pointer_counter= 0;
 101   uint32_t pointer_per_server= MEMCACHED_POINTS_PER_SERVER;
 102   uint32_t pointer_per_hash= 1;
 103   uint64_t total_weight= 0;
 104   uint64_t is_ketama_weighted= 0;
 105   uint64_t is_auto_ejecting= 0;
 106   uint32_t points_per_server= 0;
 107   uint32_t live_servers= 0;
 108   struct timeval now;
 109
 110   if (gettimeofday(&now, NULL) != 0)
 111   {
 112     ptr->cached_errno = errno;
 113     return MEMCACHED_ERRNO;
 114   }
 115
 116   list = memcached_server_list(ptr);
 117
 118   /* count live servers (those without a retry delay set) */
 119   is_auto_ejecting= memcached_behavior_get(ptr, MEMCACHED_BEHAVIOR_AUTO_EJECT_HOSTS);
 120   if (is_auto_ejecting)
 121   {
 122     live_servers= 0;
 123     ptr->next_distribution_rebuild= 0;
 124     for (host_index= 0; host_index < memcached_server_count(ptr); ++host_index)
 125     {
 126       if (list[host_index].next_retry <= now.tv_sec)
 127         live_servers++;
 128       else
 129       {
 130         if (ptr->next_distribution_rebuild == 0 || list[host_index].next_retry < ptr->next_distribution_rebuild)
 131           ptr->next_distribution_rebuild= list[host_index].next_retry;
 132       }
 133     }
 134   }
 135   else
 136   {
 137     live_servers= memcached_server_count(ptr);
 138   }
 139
 140   is_ketama_weighted= memcached_behavior_get(ptr, MEMCACHED_BEHAVIOR_KETAMA_WEIGHTED);
 141   points_per_server= (uint32_t) (is_ketama_weighted ? MEMCACHED_POINTS_PER_SERVER_KETAMA : MEMCACHED_POINTS_PER_SERVER);
 142
 143   if (live_servers == 0)
 144     return MEMCACHED_SUCCESS;
 145
 146   if (live_servers > ptr->continuum_count)
 147   {
 148     memcached_continuum_item_st *new_ptr;
 149
 150     new_ptr= libmemcached_realloc(ptr, ptr->continuum,
 151                                   sizeof(memcached_continuum_item_st) * (live_servers + MEMCACHED_CONTINUUM_ADDITION) * points_per_server);
 152
 153     if (new_ptr == 0)
 154       return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 155
 156     ptr->continuum= new_ptr;
 157     ptr->continuum_count= live_servers + MEMCACHED_CONTINUUM_ADDITION;
 158   }
 159
 160   if (is_ketama_weighted)
 161   {
 162     for (host_index = 0; host_index < memcached_server_count(ptr); ++host_index)
 163     {
 164       if (list[host_index].weight == 0)
 165       {
 166         list[host_index].weight = 1;
 167       }
 168       if (!is_auto_ejecting || list[host_index].next_retry <= now.tv_sec)
 169         total_weight += list[host_index].weight;
 170     }
 171   }
 172
 173   for (host_index = 0; host_index < memcached_server_count(ptr); ++host_index)
 174   {
 175     if (is_auto_ejecting && list[host_index].next_retry > now.tv_sec)
 176       continue;
 177
 178     if (is_ketama_weighted)
 179     {
 180         float pct = (float)list[host_index].weight / (float)total_weight;
 181         pointer_per_server= (uint32_t) ((floorf((float) (pct * MEMCACHED_POINTS_PER_SERVER_KETAMA / 4 * (float)live_servers + 0.0000000001))) * 4);
 182         pointer_per_hash= 4;
 183 #ifdef DEBUG
 184         printf("ketama_weighted:%s|%d|%llu|%u\n",
 185                list[host_index].hostname,
 186                list[host_index].port,
 187                (unsigned long long)list[host_index].weight,
 188                pointer_per_server);
 189 #endif
 190     }
 191
 192
 193     if (ptr->distribution == MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA_SPY)
 194     {
 195       for (pointer_index= 0;
 196            pointer_index < pointer_per_server / pointer_per_hash;
 197            pointer_index++)
 198       {
 199         char sort_host[MEMCACHED_MAX_HOST_SORT_LENGTH]= "";
 200         size_t sort_host_length;
 201
 202         // Spymemcached ketema key format is: hostname/ip:port-index
 203         // If hostname is not available then: /ip:port-index
 204         sort_host_length= (size_t) snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH,
 205                                             "/%s:%u-%u",
 206                                             list[host_index].hostname,
 207                                             (uint32_t)list[host_index].port,
 208                                             pointer_index);
 209 #ifdef DEBUG
 210         printf("update_continuum: key is %s\n", sort_host);
 211 #endif
 212
 213         WATCHPOINT_ASSERT(sort_host_length);
 214
 215         if (is_ketama_weighted)
 216         {
 217           for (uint32_t x = 0; x < pointer_per_hash; x++)
 218           {
 219              value= ketama_server_hash(sort_host, (uint32_t) sort_host_length, x);
 220              ptr->continuum[continuum_index].index= host_index;
 221              ptr->continuum[continuum_index++].value= value;
 222           }
 223         }
 224         else
 225         {
 226           value= hashkit_digest(&ptr->distribution_hashkit, sort_host, sort_host_length);
 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           for (uint32_t x = 0; x < pointer_per_hash; x++)
 262           {
 263              value= ketama_server_hash(sort_host, (uint32_t) sort_host_length, (int) x);
 264              ptr->continuum[continuum_index].index= host_index;
 265              ptr->continuum[continuum_index++].value= value;
 266           }
 267         }
 268         else
 269         {
 270           value= hashkit_digest(&ptr->distribution_hashkit, sort_host, sort_host_length);
 271           ptr->continuum[continuum_index].index= host_index;
 272           ptr->continuum[continuum_index++].value= value;
 273         }
 274       }
 275     }
 276
 277     pointer_counter+= pointer_per_server;
 278   }
 279
 280   WATCHPOINT_ASSERT(ptr);
 281   WATCHPOINT_ASSERT(ptr->continuum);
 282   WATCHPOINT_ASSERT(memcached_server_count(ptr) * MEMCACHED_POINTS_PER_SERVER <= MEMCACHED_CONTINUUM_SIZE);
 283   ptr->continuum_points_counter= pointer_counter;
 284   qsort(ptr->continuum, ptr->continuum_points_counter, sizeof(memcached_continuum_item_st), continuum_item_cmp);
 285
 286 #ifdef DEBUG
 287   for (pointer_index= 0; memcached_server_count(ptr) && pointer_index < ((live_servers * MEMCACHED_POINTS_PER_SERVER) - 1); pointer_index++)
 288   {
 289     WATCHPOINT_ASSERT(ptr->continuum[pointer_index].value <= ptr->continuum[pointer_index + 1].value);
 290   }
 291 #endif
 292
 293   return MEMCACHED_SUCCESS;
 294 }
 295
 296
 297 memcached_return_t memcached_server_push(memcached_st *ptr, memcached_server_st *list)
 298 {
 299   uint32_t count;
 300   memcached_server_st *new_host_list;
 301
 302   if (! list)
 303     return MEMCACHED_SUCCESS;
 304
 305   count= memcached_servers_count(list);
 306   new_host_list= libmemcached_realloc(ptr, memcached_server_list(ptr),
 307                                       sizeof(memcached_server_instance_st) * (count + memcached_server_count(ptr)));
 308
 309   if (! new_host_list)
 310     return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 311
 312   memcached_server_list_set(ptr, new_host_list);
 313
 314   for (uint32_t x= 0; x < count; x++)
 315   {
 316     memcached_server_instance_st *instance;
 317
 318     if ((ptr->flags.use_udp && list[x].type != MEMCACHED_CONNECTION_UDP)
 319             || ((list[x].type == MEMCACHED_CONNECTION_UDP)
 320             && ! (ptr->flags.use_udp)) )
 321       return MEMCACHED_INVALID_HOST_PROTOCOL;
 322
 323     WATCHPOINT_ASSERT(list[x].hostname[0] != 0);
 324
 325     instance= memcached_server_instance_fetch(ptr, memcached_server_count(ptr));
 326
 327     /* TODO check return type */
 328     (void)memcached_server_create_with(ptr, instance, list[x].hostname,
 329                                        list[x].port, list[x].weight, list[x].type);
 330     ptr->number_of_hosts++;
 331   }
 332
 333   // Provides backwards compatibility with server list.
 334   {
 335     memcached_server_instance_st *instance;
 336     instance= memcached_server_instance_fetch(ptr, 0);
 337     instance->number_of_hosts= memcached_server_count(ptr);
 338   }
 339
 340   return run_distribution(ptr);
 341 }
 342
 343 memcached_return_t memcached_server_add_unix_socket(memcached_st *ptr,
 344                                                     const char *filename)
 345 {
 346   return memcached_server_add_unix_socket_with_weight(ptr, filename, 0);
 347 }
 348
 349 memcached_return_t memcached_server_add_unix_socket_with_weight(memcached_st *ptr,
 350                                                                 const char *filename,
 351                                                                 uint32_t weight)
 352 {
 353   if (! filename)
 354     return MEMCACHED_FAILURE;
 355
 356   return server_add(ptr, filename, 0, weight, MEMCACHED_CONNECTION_UNIX_SOCKET);
 357 }
 358
 359 memcached_return_t memcached_server_add_udp(memcached_st *ptr,
 360                                             const char *hostname,
 361                                             in_port_t port)
 362 {
 363   return memcached_server_add_udp_with_weight(ptr, hostname, port, 0);
 364 }
 365
 366 memcached_return_t memcached_server_add_udp_with_weight(memcached_st *ptr,
 367                                                         const char *hostname,
 368                                                         in_port_t port,
 369                                                         uint32_t weight)
 370 {
 371   if (! port)
 372     port= MEMCACHED_DEFAULT_PORT;
 373
 374   if (! hostname)
 375     hostname= "localhost";
 376
 377   return server_add(ptr, hostname, port, weight, MEMCACHED_CONNECTION_UDP);
 378 }
 379
 380 memcached_return_t memcached_server_add(memcached_st *ptr,
 381                                         const char *hostname,
 382                                         in_port_t port)
 383 {
 384   return memcached_server_add_with_weight(ptr, hostname, port, 0);
 385 }
 386
 387 memcached_return_t memcached_server_add_with_weight(memcached_st *ptr,
 388                                                     const char *hostname,
 389                                                     in_port_t port,
 390                                                     uint32_t weight)
 391 {
 392   if (! port)
 393     port= MEMCACHED_DEFAULT_PORT;
 394
 395   if (! hostname)
 396     hostname= "localhost";
 397
 398   return server_add(ptr, hostname, port, weight, MEMCACHED_CONNECTION_TCP);
 399 }
 400
 401 static memcached_return_t server_add(memcached_st *ptr, const char *hostname,
 402                                      in_port_t port,
 403                                      uint32_t weight,
 404                                      memcached_connection_t type)
 405 {
 406   memcached_server_instance_st *new_host_list;
 407   memcached_server_instance_st *instance;
 408
 409   if ( (ptr->flags.use_udp && type != MEMCACHED_CONNECTION_UDP)
 410       || ( (type == MEMCACHED_CONNECTION_UDP) && (! ptr->flags.use_udp) ) )
 411     return MEMCACHED_INVALID_HOST_PROTOCOL;
 412
 413   new_host_list= libmemcached_realloc(ptr, memcached_server_list(ptr),
 414                                       sizeof(memcached_server_instance_st) * (ptr->number_of_hosts + 1));
 415
 416   if (new_host_list == NULL)
 417     return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 418
 419   memcached_server_list_set(ptr, new_host_list);
 420
 421   /* TODO: Check return type */
 422   instance= memcached_server_instance_fetch(ptr, memcached_server_count(ptr));
 423   (void)memcached_server_create_with(ptr, instance, hostname, port, weight, type);
 424   ptr->number_of_hosts++;
 425
 426   instance= memcached_server_instance_fetch(ptr, 0);
 427   memcached_servers_set_count(instance, memcached_server_count(ptr));
 428
 429   return run_distribution(ptr);
 430 }
 431
 432 /**
 433   @todo allow lists to query themselves even if they lack a root
 434 */
 435 memcached_return_t memcached_server_remove(memcached_server_st *st_ptr)
 436 {
 437   uint32_t x, host_index;
 438   memcached_st *root= (memcached_st *)st_ptr->root;
 439   memcached_server_st *list;
 440
 441   if (root == NULL)
 442     return MEMCACHED_FAILURE;
 443
 444   list= memcached_server_list(root);
 445
 446   for (x= 0, host_index= 0; x < memcached_server_count(root); x++)
 447   {
 448     if (strncmp(list[x].hostname, st_ptr->hostname, MEMCACHED_MAX_HOST_LENGTH) != 0 || list[x].port != st_ptr->port)
 449     {
 450       if (host_index != x)
 451         memcpy(list+host_index, list+x, sizeof(memcached_server_st));
 452       host_index++;
 453     }
 454   }
 455   root->number_of_hosts= host_index;
 456
 457   if (st_ptr->address_info)
 458   {
 459     freeaddrinfo(st_ptr->address_info);
 460     st_ptr->address_info= NULL;
 461   }
 462   run_distribution(root);
 463
 464   return MEMCACHED_SUCCESS;
 465 }
 466
 467 memcached_server_st *memcached_server_list_append(memcached_server_st *ptr,
 468                                                   const char *hostname, in_port_t port,
 469                                                   memcached_return_t *error)
 470 {
 471   return memcached_server_list_append_with_weight(ptr, hostname, port, 0, error);
 472 }
 473
 474 memcached_server_st *memcached_server_list_append_with_weight(memcached_server_st *ptr,
 475                                                               const char *hostname, in_port_t port,
 476                                                               uint32_t weight,
 477                                                               memcached_return_t *error)
 478 {
 479   unsigned int count;
 480   memcached_server_instance_st *new_host_list;
 481
 482   if (hostname == NULL || error == NULL)
 483     return NULL;
 484
 485   if (! port)
 486     port= MEMCACHED_DEFAULT_PORT;
 487
 488   /* Increment count for hosts */
 489   count= 1;
 490   if (ptr != NULL)
 491   {
 492     count+= memcached_servers_count(ptr);
 493   }
 494
 495   new_host_list= (memcached_server_instance_st *)realloc(ptr, sizeof(memcached_server_instance_st) * count);
 496   if (!new_host_list)
 497   {
 498     *error= MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 499     return NULL;
 500   }
 501
 502   /* TODO: Check return type */
 503   memcached_server_create_with(NULL, &new_host_list[count-1], hostname, port, weight, MEMCACHED_CONNECTION_TCP);
 504
 505   /* Backwards compatibility hack */
 506   memcached_servers_set_count(new_host_list, count);
 507
 508   *error= MEMCACHED_SUCCESS;
 509   return new_host_list;
 510 }