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           for (uint32_t x = 0; x < pointer_per_hash; x++)
 217           {
 218              value= ketama_server_hash(sort_host, (uint32_t) sort_host_length, (int) x);
 219              ptr->continuum[continuum_index].index= host_index;
 220              ptr->continuum[continuum_index++].value= value;
 221           }
 222         }
 223         else
 224         {
 225           value= hashkit_digest(&ptr->distribution_hashkit, sort_host, sort_host_length);
 226           ptr->continuum[continuum_index].index= host_index;
 227           ptr->continuum[continuum_index++].value= value;
 228         }
 229       }
 230     }
 231     else
 232     {
 233       for (pointer_index= 1;
 234            pointer_index <= pointer_per_server / pointer_per_hash;
 235            pointer_index++)
 236       {
 237         char sort_host[MEMCACHED_MAX_HOST_SORT_LENGTH]= "";
 238         size_t sort_host_length;
 239
 240         if (list[host_index].port == MEMCACHED_DEFAULT_PORT)
 241         {
 242           sort_host_length= (size_t) snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH,
 243                                               "%s-%u",
 244                                               list[host_index].hostname,
 245                                               pointer_index - 1);
 246         }
 247         else
 248         {
 249           sort_host_length= (size_t) snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH,
 250                                               "%s:%u-%u",
 251                                               list[host_index].hostname,
 252                                               (uint32_t)list[host_index].port,
 253                                               pointer_index - 1);
 254         }
 255
 256         WATCHPOINT_ASSERT(sort_host_length);
 257
 258         if (is_ketama_weighted)
 259         {
 260           for (uint32_t x = 0; x < pointer_per_hash; x++)
 261           {
 262              value= ketama_server_hash(sort_host, (uint32_t) sort_host_length, (int) x);
 263              ptr->continuum[continuum_index].index= host_index;
 264              ptr->continuum[continuum_index++].value= value;
 265           }
 266         }
 267         else
 268         {
 269           value= hashkit_digest(&ptr->distribution_hashkit, sort_host, sort_host_length);
 270           ptr->continuum[continuum_index].index= host_index;
 271           ptr->continuum[continuum_index++].value= value;
 272         }
 273       }
 274     }
 275
 276     pointer_counter+= pointer_per_server;
 277   }
 278
 279   WATCHPOINT_ASSERT(ptr);
 280   WATCHPOINT_ASSERT(ptr->continuum);
 281   WATCHPOINT_ASSERT(memcached_server_count(ptr) * MEMCACHED_POINTS_PER_SERVER <= MEMCACHED_CONTINUUM_SIZE);
 282   ptr->continuum_points_counter= pointer_counter;
 283   qsort(ptr->continuum, ptr->continuum_points_counter, sizeof(memcached_continuum_item_st), continuum_item_cmp);
 284
 285 #ifdef DEBUG
 286   for (pointer_index= 0; memcached_server_count(ptr) && pointer_index < ((live_servers * MEMCACHED_POINTS_PER_SERVER) - 1); pointer_index++)
 287   {
 288     WATCHPOINT_ASSERT(ptr->continuum[pointer_index].value <= ptr->continuum[pointer_index + 1].value);
 289   }
 290 #endif
 291
 292   return MEMCACHED_SUCCESS;
 293 }
 294
 295
 296 memcached_return_t memcached_server_push(memcached_st *ptr, memcached_server_st *list)
 297 {
 298   uint32_t count;
 299   memcached_server_st *new_host_list;
 300
 301   if (! list)
 302     return MEMCACHED_SUCCESS;
 303
 304   count= memcached_servers_count(list);
 305   new_host_list= libmemcached_realloc(ptr, memcached_server_list(ptr),
 306                                       sizeof(memcached_server_instance_st) * (count + memcached_server_count(ptr)));
 307
 308   if (! new_host_list)
 309     return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 310
 311   memcached_server_list_set(ptr, new_host_list);
 312
 313   for (uint32_t x= 0; x < count; x++)
 314   {
 315     memcached_server_instance_st *instance;
 316
 317     if ((ptr->flags.use_udp && list[x].type != MEMCACHED_CONNECTION_UDP)
 318             || ((list[x].type == MEMCACHED_CONNECTION_UDP)
 319             && ! (ptr->flags.use_udp)) )
 320       return MEMCACHED_INVALID_HOST_PROTOCOL;
 321
 322     WATCHPOINT_ASSERT(list[x].hostname[0] != 0);
 323
 324     instance= memcached_server_instance_fetch(ptr, memcached_server_count(ptr));
 325
 326     /* TODO check return type */
 327     (void)memcached_server_create_with(ptr, instance, list[x].hostname,
 328                                        list[x].port, list[x].weight, list[x].type);
 329     ptr->number_of_hosts++;
 330   }
 331
 332   // Provides backwards compatibility with server list.
 333   {
 334     memcached_server_instance_st *instance;
 335     instance= memcached_server_instance_fetch(ptr, 0);
 336     instance->number_of_hosts= memcached_server_count(ptr);
 337   }
 338
 339   return run_distribution(ptr);
 340 }
 341
 342 memcached_return_t memcached_server_add_unix_socket(memcached_st *ptr,
 343                                                     const char *filename)
 344 {
 345   return memcached_server_add_unix_socket_with_weight(ptr, filename, 0);
 346 }
 347
 348 memcached_return_t memcached_server_add_unix_socket_with_weight(memcached_st *ptr,
 349                                                                 const char *filename,
 350                                                                 uint32_t weight)
 351 {
 352   if (! filename)
 353     return MEMCACHED_FAILURE;
 354
 355   return server_add(ptr, filename, 0, weight, MEMCACHED_CONNECTION_UNIX_SOCKET);
 356 }
 357
 358 memcached_return_t memcached_server_add_udp(memcached_st *ptr,
 359                                             const char *hostname,
 360                                             in_port_t port)
 361 {
 362   return memcached_server_add_udp_with_weight(ptr, hostname, port, 0);
 363 }
 364
 365 memcached_return_t memcached_server_add_udp_with_weight(memcached_st *ptr,
 366                                                         const char *hostname,
 367                                                         in_port_t port,
 368                                                         uint32_t weight)
 369 {
 370   if (! port)
 371     port= MEMCACHED_DEFAULT_PORT;
 372
 373   if (! hostname)
 374     hostname= "localhost";
 375
 376   return server_add(ptr, hostname, port, weight, MEMCACHED_CONNECTION_UDP);
 377 }
 378
 379 memcached_return_t memcached_server_add(memcached_st *ptr,
 380                                         const char *hostname,
 381                                         in_port_t port)
 382 {
 383   return memcached_server_add_with_weight(ptr, hostname, port, 0);
 384 }
 385
 386 memcached_return_t memcached_server_add_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_TCP);
 398 }
 399
 400 static memcached_return_t server_add(memcached_st *ptr, const char *hostname,
 401                                      in_port_t port,
 402                                      uint32_t weight,
 403                                      memcached_connection_t type)
 404 {
 405   memcached_server_instance_st *new_host_list;
 406   memcached_server_instance_st *instance;
 407
 408   if ( (ptr->flags.use_udp && type != MEMCACHED_CONNECTION_UDP)
 409       || ( (type == MEMCACHED_CONNECTION_UDP) && (! ptr->flags.use_udp) ) )
 410     return MEMCACHED_INVALID_HOST_PROTOCOL;
 411
 412   new_host_list= libmemcached_realloc(ptr, memcached_server_list(ptr),
 413                                       sizeof(memcached_server_instance_st) * (ptr->number_of_hosts + 1));
 414
 415   if (new_host_list == NULL)
 416     return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 417
 418   memcached_server_list_set(ptr, new_host_list);
 419
 420   /* TODO: Check return type */
 421   instance= memcached_server_instance_fetch(ptr, memcached_server_count(ptr));
 422   (void)memcached_server_create_with(ptr, instance, hostname, port, weight, type);
 423   ptr->number_of_hosts++;
 424
 425   instance= memcached_server_instance_fetch(ptr, 0);
 426   memcached_servers_set_count(instance, memcached_server_count(ptr));
 427
 428   return run_distribution(ptr);
 429 }
 430
 431 /**
 432   @todo allow lists to query themselves even if they lack a root
 433 */
 434 memcached_return_t memcached_server_remove(memcached_server_st *st_ptr)
 435 {
 436   uint32_t x, host_index;
 437   memcached_st *root= (memcached_st *)st_ptr->root;
 438   memcached_server_st *list;
 439
 440   if (root == NULL)
 441     return MEMCACHED_FAILURE;
 442
 443   list= memcached_server_list(root);
 444
 445   for (x= 0, host_index= 0; x < memcached_server_count(root); x++)
 446   {
 447     if (strncmp(list[x].hostname, st_ptr->hostname, MEMCACHED_MAX_HOST_LENGTH) != 0 || list[x].port != st_ptr->port)
 448     {
 449       if (host_index != x)
 450         memcpy(list+host_index, list+x, sizeof(memcached_server_st));
 451       host_index++;
 452     }
 453   }
 454   root->number_of_hosts= host_index;
 455
 456   if (st_ptr->address_info)
 457   {
 458     freeaddrinfo(st_ptr->address_info);
 459     st_ptr->address_info= NULL;
 460   }
 461   run_distribution(root);
 462
 463   return MEMCACHED_SUCCESS;
 464 }
 465
 466 memcached_server_st *memcached_server_list_append(memcached_server_st *ptr,
 467                                                   const char *hostname, in_port_t port,
 468                                                   memcached_return_t *error)
 469 {
 470   return memcached_server_list_append_with_weight(ptr, hostname, port, 0, error);
 471 }
 472
 473 memcached_server_st *memcached_server_list_append_with_weight(memcached_server_st *ptr,
 474                                                               const char *hostname, in_port_t port,
 475                                                               uint32_t weight,
 476                                                               memcached_return_t *error)
 477 {
 478   unsigned int count;
 479   memcached_server_instance_st *new_host_list;
 480
 481   if (hostname == NULL || error == NULL)
 482     return NULL;
 483
 484   if (! port)
 485     port= MEMCACHED_DEFAULT_PORT;
 486
 487   /* Increment count for hosts */
 488   count= 1;
 489   if (ptr != NULL)
 490   {
 491     count+= memcached_servers_count(ptr);
 492   }
 493
 494   new_host_list= (memcached_server_instance_st *)realloc(ptr, sizeof(memcached_server_instance_st) * count);
 495   if (!new_host_list)
 496   {
 497     *error= MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 498     return NULL;
 499   }
 500
 501   /* TODO: Check return type */
 502   memcached_server_create_with(NULL, &new_host_list[count-1], hostname, port, weight, MEMCACHED_CONNECTION_TCP);
 503
 504   /* Backwards compatibility hack */
 505   memcached_servers_set_count(new_host_list, count);
 506
 507   *error= MEMCACHED_SUCCESS;
 508   return new_host_list;
 509 }