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

   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 host_index;
 108   uint32_t continuum_index= 0;
 109   uint32_t value;
 110   memcached_server_st *list;
 111   uint32_t pointer_index;
 112   uint32_t pointer_counter= 0;
 113   uint32_t pointer_per_server= MEMCACHED_POINTS_PER_SERVER;
 114   uint32_t pointer_per_hash= 1;
 115   uint64_t total_weight= 0;
 116   uint64_t is_ketama_weighted= 0;
 117   uint64_t is_auto_ejecting= 0;
 118   uint32_t points_per_server= 0;
 119   uint32_t live_servers= 0;
 120   struct timeval now;
 121
 122   if (gettimeofday(&now, NULL) != 0)
 123   {
 124     memcached_set_errno(ptr, errno, NULL);
 125     return MEMCACHED_ERRNO;
 126   }
 127
 128   list = memcached_server_list(ptr);
 129
 130   /* count live servers (those without a retry delay set) */
 131   is_auto_ejecting= _is_auto_eject_host(ptr);
 132   if (is_auto_ejecting)
 133   {
 134     live_servers= 0;
 135     ptr->ketama.next_distribution_rebuild= 0;
 136     for (host_index= 0; host_index < memcached_server_count(ptr); ++host_index)
 137     {
 138       if (list[host_index].next_retry <= now.tv_sec)
 139         live_servers++;
 140       else
 141       {
 142         if (ptr->ketama.next_distribution_rebuild == 0 || list[host_index].next_retry < ptr->ketama.next_distribution_rebuild)
 143           ptr->ketama.next_distribution_rebuild= list[host_index].next_retry;
 144       }
 145     }
 146   }
 147   else
 148   {
 149     live_servers= memcached_server_count(ptr);
 150   }
 151
 152   is_ketama_weighted= memcached_behavior_get(ptr, MEMCACHED_BEHAVIOR_KETAMA_WEIGHTED);
 153   points_per_server= (uint32_t) (is_ketama_weighted ? MEMCACHED_POINTS_PER_SERVER_KETAMA : MEMCACHED_POINTS_PER_SERVER);
 154
 155   if (live_servers == 0)
 156     return MEMCACHED_SUCCESS;
 157
 158   if (live_servers > ptr->ketama.continuum_count)
 159   {
 160     memcached_continuum_item_st *new_ptr;
 161
 162     new_ptr= libmemcached_realloc(ptr, ptr->ketama.continuum,
 163                                   sizeof(memcached_continuum_item_st) * (live_servers + MEMCACHED_CONTINUUM_ADDITION) * points_per_server);
 164
 165     if (new_ptr == 0)
 166       return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 167
 168     ptr->ketama.continuum= new_ptr;
 169     ptr->ketama.continuum_count= live_servers + MEMCACHED_CONTINUUM_ADDITION;
 170   }
 171
 172   if (is_ketama_weighted)
 173   {
 174     for (host_index = 0; host_index < memcached_server_count(ptr); ++host_index)
 175     {
 176       if (list[host_index].weight == 0)
 177       {
 178         list[host_index].weight = 1;
 179       }
 180       if (! is_auto_ejecting || list[host_index].next_retry <= now.tv_sec)
 181         total_weight += list[host_index].weight;
 182     }
 183   }
 184
 185   for (host_index= 0; host_index < memcached_server_count(ptr); ++host_index)
 186   {
 187     if (is_auto_ejecting && list[host_index].next_retry > now.tv_sec)
 188       continue;
 189
 190     if (is_ketama_weighted)
 191     {
 192         float pct = (float)list[host_index].weight / (float)total_weight;
 193         pointer_per_server= (uint32_t) ((floorf((float) (pct * MEMCACHED_POINTS_PER_SERVER_KETAMA / 4 * (float)live_servers + 0.0000000001))) * 4);
 194         pointer_per_hash= 4;
 195 #ifdef DEBUG
 196         printf("ketama_weighted:%s|%d|%llu|%u\n",
 197                list[host_index].hostname,
 198                list[host_index].port,
 199                (unsigned long long)list[host_index].weight,
 200                pointer_per_server);
 201 #endif
 202     }
 203
 204
 205     if (ptr->distribution == MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA_SPY)
 206     {
 207       for (pointer_index= 0;
 208            pointer_index < pointer_per_server / pointer_per_hash;
 209            pointer_index++)
 210       {
 211         char sort_host[MEMCACHED_MAX_HOST_SORT_LENGTH]= "";
 212         int sort_host_length;
 213
 214         // Spymemcached ketema key format is: hostname/ip:port-index
 215         // If hostname is not available then: /ip:port-index
 216         sort_host_length= snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH,
 217                                    "/%s:%u-%u",
 218                                    list[host_index].hostname,
 219                                    (uint32_t)list[host_index].port,
 220                                    pointer_index);
 221
 222         if (sort_host_length >= MEMCACHED_MAX_HOST_SORT_LENGTH || sort_host_length < 0)
 223         {
 224           return MEMCACHED_FAILURE;
 225         }
 226 #ifdef DEBUG
 227         printf("update_continuum: key is %s\n", sort_host);
 228 #endif
 229
 230         WATCHPOINT_ASSERT(sort_host_length);
 231
 232         if (is_ketama_weighted)
 233         {
 234           for (uint32_t x= 0; x < pointer_per_hash; x++)
 235           {
 236              value= ketama_server_hash(sort_host, (size_t)sort_host_length, x);
 237              ptr->ketama.continuum[continuum_index].index= host_index;
 238              ptr->ketama.continuum[continuum_index++].value= value;
 239           }
 240         }
 241         else
 242         {
 243           value= hashkit_digest(&ptr->distribution_hashkit, sort_host, (size_t)sort_host_length);
 244           ptr->ketama.continuum[continuum_index].index= host_index;
 245           ptr->ketama.continuum[continuum_index++].value= value;
 246         }
 247       }
 248     }
 249     else
 250     {
 251       for (pointer_index= 1;
 252            pointer_index <= pointer_per_server / pointer_per_hash;
 253            pointer_index++)
 254       {
 255         char sort_host[MEMCACHED_MAX_HOST_SORT_LENGTH]= "";
 256         int sort_host_length;
 257
 258         if (list[host_index].port == MEMCACHED_DEFAULT_PORT)
 259         {
 260           sort_host_length= snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH,
 261                                      "%s-%u",
 262                                      list[host_index].hostname,
 263                                      pointer_index - 1);
 264         }
 265         else
 266         {
 267           sort_host_length= snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH,
 268                                      "%s:%u-%u",
 269                                      list[host_index].hostname,
 270                                      (uint32_t)list[host_index].port,
 271                                      pointer_index - 1);
 272         }
 273
 274         if (sort_host_length >= MEMCACHED_MAX_HOST_SORT_LENGTH || sort_host_length < 0)
 275         {
 276           return MEMCACHED_FAILURE;
 277         }
 278
 279         WATCHPOINT_ASSERT(sort_host_length);
 280
 281         if (is_ketama_weighted)
 282         {
 283           for (uint32_t x = 0; x < pointer_per_hash; x++)
 284           {
 285              value= ketama_server_hash(sort_host, (size_t)sort_host_length, x);
 286              ptr->ketama.continuum[continuum_index].index= host_index;
 287              ptr->ketama.continuum[continuum_index++].value= value;
 288           }
 289         }
 290         else
 291         {
 292           value= hashkit_digest(&ptr->distribution_hashkit, sort_host, (size_t)sort_host_length);
 293           ptr->ketama.continuum[continuum_index].index= host_index;
 294           ptr->ketama.continuum[continuum_index++].value= value;
 295         }
 296       }
 297     }
 298
 299     pointer_counter+= pointer_per_server;
 300   }
 301
 302   WATCHPOINT_ASSERT(ptr);
 303   WATCHPOINT_ASSERT(ptr->continuum);
 304   WATCHPOINT_ASSERT(memcached_server_count(ptr) * MEMCACHED_POINTS_PER_SERVER <= MEMCACHED_CONTINUUM_SIZE);
 305   ptr->ketama.continuum_points_counter= pointer_counter;
 306   qsort(ptr->ketama.continuum, ptr->ketama.continuum_points_counter, sizeof(memcached_continuum_item_st), continuum_item_cmp);
 307
 308 #ifdef DEBUG
 309   for (pointer_index= 0; memcached_server_count(ptr) && pointer_index < ((live_servers * MEMCACHED_POINTS_PER_SERVER) - 1); pointer_index++)
 310   {
 311     WATCHPOINT_ASSERT(ptr->continuum[pointer_index].value <= ptr->continuum[pointer_index + 1].value);
 312   }
 313 #endif
 314
 315   return MEMCACHED_SUCCESS;
 316 }
 317
 318
 319 memcached_return_t memcached_server_push(memcached_st *ptr, const memcached_server_list_st list)
 320 {
 321   uint32_t count;
 322   memcached_server_st *new_host_list;
 323
 324   if (! list)
 325     return MEMCACHED_SUCCESS;
 326
 327   count= memcached_server_list_count(list);
 328   new_host_list= libmemcached_realloc(ptr, memcached_server_list(ptr),
 329                                       sizeof(memcached_server_st) * (count + memcached_server_count(ptr)));
 330
 331   if (! new_host_list)
 332     return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 333
 334   memcached_server_list_set(ptr, new_host_list);
 335
 336   for (uint32_t x= 0; x < count; x++)
 337   {
 338     memcached_server_write_instance_st instance;
 339
 340     if ((ptr->flags.use_udp && list[x].type != MEMCACHED_CONNECTION_UDP)
 341             || ((list[x].type == MEMCACHED_CONNECTION_UDP)
 342             && ! (ptr->flags.use_udp)) )
 343     {
 344       return MEMCACHED_INVALID_HOST_PROTOCOL;
 345     }
 346
 347     WATCHPOINT_ASSERT(list[x].hostname[0] != 0);
 348
 349     instance= memcached_server_instance_fetch(ptr, memcached_server_count(ptr));
 350
 351     /* TODO check return type */
 352     (void)memcached_server_create_with(ptr, instance, list[x].hostname,
 353                                        list[x].port, list[x].weight, list[x].type);
 354     ptr->number_of_hosts++;
 355   }
 356
 357   // Provides backwards compatibility with server list.
 358   {
 359     memcached_server_write_instance_st instance;
 360     instance= memcached_server_instance_fetch(ptr, 0);
 361     instance->number_of_hosts= memcached_server_count(ptr);
 362   }
 363
 364   return run_distribution(ptr);
 365 }
 366
 367 memcached_return_t memcached_server_add_unix_socket(memcached_st *ptr,
 368                                                     const char *filename)
 369 {
 370   return memcached_server_add_unix_socket_with_weight(ptr, filename, 0);
 371 }
 372
 373 memcached_return_t memcached_server_add_unix_socket_with_weight(memcached_st *ptr,
 374                                                                 const char *filename,
 375                                                                 uint32_t weight)
 376 {
 377   if (! filename)
 378     return MEMCACHED_FAILURE;
 379
 380   return server_add(ptr, filename, 0, weight, MEMCACHED_CONNECTION_UNIX_SOCKET);
 381 }
 382
 383 memcached_return_t memcached_server_add_udp(memcached_st *ptr,
 384                                             const char *hostname,
 385                                             in_port_t port)
 386 {
 387   return memcached_server_add_udp_with_weight(ptr, hostname, port, 0);
 388 }
 389
 390 memcached_return_t memcached_server_add_udp_with_weight(memcached_st *ptr,
 391                                                         const char *hostname,
 392                                                         in_port_t port,
 393                                                         uint32_t weight)
 394 {
 395   if (! port)
 396     port= MEMCACHED_DEFAULT_PORT;
 397
 398   if (! hostname)
 399     hostname= "localhost";
 400
 401   return server_add(ptr, hostname, port, weight, MEMCACHED_CONNECTION_UDP);
 402 }
 403
 404 memcached_return_t memcached_server_add(memcached_st *ptr,
 405                                         const char *hostname,
 406                                         in_port_t port)
 407 {
 408   return memcached_server_add_with_weight(ptr, hostname, port, 0);
 409 }
 410
 411 memcached_return_t memcached_server_add_with_weight(memcached_st *ptr,
 412                                                     const char *hostname,
 413                                                     in_port_t port,
 414                                                     uint32_t weight)
 415 {
 416   if (! port)
 417     port= MEMCACHED_DEFAULT_PORT;
 418
 419   if (! hostname)
 420     hostname= "localhost";
 421
 422   return server_add(ptr, hostname, port, weight, MEMCACHED_CONNECTION_TCP);
 423 }
 424
 425 static memcached_return_t server_add(memcached_st *ptr, const char *hostname,
 426                                      in_port_t port,
 427                                      uint32_t weight,
 428                                      memcached_connection_t type)
 429 {
 430   memcached_server_st *new_host_list;
 431   memcached_server_write_instance_st instance;
 432
 433   if ( (ptr->flags.use_udp && type != MEMCACHED_CONNECTION_UDP)
 434       || ( (type == MEMCACHED_CONNECTION_UDP) && (! ptr->flags.use_udp) ) )
 435     return MEMCACHED_INVALID_HOST_PROTOCOL;
 436
 437   new_host_list= libmemcached_realloc(ptr, memcached_server_list(ptr),
 438                                       sizeof(memcached_server_st) * (ptr->number_of_hosts + 1));
 439
 440   if (new_host_list == NULL)
 441     return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 442
 443   memcached_server_list_set(ptr, new_host_list);
 444
 445   /* TODO: Check return type */
 446   instance= memcached_server_instance_fetch(ptr, memcached_server_count(ptr));
 447   (void)memcached_server_create_with(ptr, instance, hostname, port, weight, type);
 448   ptr->number_of_hosts++;
 449
 450   instance= memcached_server_instance_fetch(ptr, 0);
 451   memcached_servers_set_count(instance, memcached_server_count(ptr));
 452
 453   return run_distribution(ptr);
 454 }
 455
 456 memcached_return_t memcached_server_add_parsed(memcached_st *ptr,
 457                                                const char *hostname,
 458                                                size_t hostname_length,
 459                                                in_port_t port,
 460                                                uint32_t weight)
 461 {
 462   char buffer[NI_MAXHOST];
 463
 464   memcpy(buffer, hostname, hostname_length);
 465   buffer[hostname_length]= 0;
 466
 467   return server_add(ptr, buffer,
 468                     port,
 469                     weight,
 470                     MEMCACHED_CONNECTION_TCP);
 471 }