git.m6w6.name Git - awesomized/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 continuum_index= 0;
 108   memcached_server_st *list;
 109   uint32_t pointer_counter= 0;
 110   uint32_t pointer_per_server= MEMCACHED_POINTS_PER_SERVER;
 111   uint32_t pointer_per_hash= 1;
 112   uint64_t total_weight= 0;
 113   uint32_t live_servers= 0;
 114   struct timeval now;
 115
 116   if (gettimeofday(&now, NULL) != 0)
 117   {
 118     memcached_set_errno(ptr, errno, NULL);
 119     return MEMCACHED_ERRNO;
 120   }
 121
 122   list= memcached_server_list(ptr);
 123
 124   /* count live servers (those without a retry delay set) */
 125   bool is_auto_ejecting= _is_auto_eject_host(ptr);
 126   if (is_auto_ejecting)
 127   {
 128     live_servers= 0;
 129     ptr->ketama.next_distribution_rebuild= 0;
 130     for (uint32_t host_index= 0; host_index < memcached_server_count(ptr); ++host_index)
 131     {
 132       if (list[host_index].next_retry <= now.tv_sec)
 133         live_servers++;
 134       else
 135       {
 136         if (ptr->ketama.next_distribution_rebuild == 0 || list[host_index].next_retry < ptr->ketama.next_distribution_rebuild)
 137           ptr->ketama.next_distribution_rebuild= list[host_index].next_retry;
 138       }
 139     }
 140   }
 141   else
 142   {
 143     live_servers= memcached_server_count(ptr);
 144   }
 145
 146   uint64_t is_ketama_weighted= memcached_behavior_get(ptr, MEMCACHED_BEHAVIOR_KETAMA_WEIGHTED);
 147   uint32_t points_per_server= (uint32_t) (is_ketama_weighted ? MEMCACHED_POINTS_PER_SERVER_KETAMA : MEMCACHED_POINTS_PER_SERVER);
 148
 149   if (live_servers == 0)
 150     return MEMCACHED_SUCCESS;
 151
 152   if (live_servers > ptr->ketama.continuum_count)
 153   {
 154     memcached_continuum_item_st *new_ptr;
 155
 156     new_ptr= libmemcached_realloc(ptr, ptr->ketama.continuum,
 157                                   sizeof(memcached_continuum_item_st) * (live_servers + MEMCACHED_CONTINUUM_ADDITION) * points_per_server);
 158
 159     if (new_ptr == 0)
 160       return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 161
 162     ptr->ketama.continuum= new_ptr;
 163     ptr->ketama.continuum_count= live_servers + MEMCACHED_CONTINUUM_ADDITION;
 164   }
 165
 166   if (is_ketama_weighted)
 167   {
 168     for (uint32_t host_index = 0; host_index < memcached_server_count(ptr); ++host_index)
 169     {
 170       if (list[host_index].weight == 0)
 171       {
 172         list[host_index].weight = 1;
 173       }
 174       if (! is_auto_ejecting || list[host_index].next_retry <= now.tv_sec)
 175         total_weight += list[host_index].weight;
 176     }
 177   }
 178
 179   for (uint32_t host_index= 0; host_index < memcached_server_count(ptr); ++host_index)
 180   {
 181     if (is_auto_ejecting && list[host_index].next_retry > now.tv_sec)
 182       continue;
 183
 184     if (is_ketama_weighted)
 185     {
 186         float pct = (float)list[host_index].weight / (float)total_weight;
 187         pointer_per_server= (uint32_t) ((floorf((float) (pct * MEMCACHED_POINTS_PER_SERVER_KETAMA / 4 * (float)live_servers + 0.0000000001))) * 4);
 188         pointer_per_hash= 4;
 189 #ifdef DEBUG
 190         printf("ketama_weighted:%s|%d|%llu|%u\n",
 191                list[host_index].hostname,
 192                list[host_index].port,
 193                (unsigned long long)list[host_index].weight,
 194                pointer_per_server);
 195 #endif
 196     }
 197
 198
 199     if (ptr->distribution == MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA_SPY)
 200     {
 201       for (uint32_t pointer_index= 0;
 202            pointer_index < pointer_per_server / pointer_per_hash;
 203            pointer_index++)
 204       {
 205         char sort_host[MEMCACHED_MAX_HOST_SORT_LENGTH]= "";
 206         int sort_host_length;
 207
 208         // Spymemcached ketema key format is: hostname/ip:port-index
 209         // If hostname is not available then: /ip:port-index
 210         sort_host_length= snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH,
 211                                    "/%s:%u-%u",
 212                                    list[host_index].hostname,
 213                                    (uint32_t)list[host_index].port,
 214                                    pointer_index);
 215
 216         if (sort_host_length >= MEMCACHED_MAX_HOST_SORT_LENGTH || sort_host_length < 0)
 217         {
 218           return MEMCACHED_FAILURE;
 219         }
 220 #ifdef DEBUG
 221         printf("update_continuum: key is %s\n", sort_host);
 222 #endif
 223
 224         WATCHPOINT_ASSERT(sort_host_length);
 225
 226         if (is_ketama_weighted)
 227         {
 228           for (uint32_t x= 0; x < pointer_per_hash; x++)
 229           {
 230             uint32_t value= ketama_server_hash(sort_host, (size_t)sort_host_length, x);
 231              ptr->ketama.continuum[continuum_index].index= host_index;
 232              ptr->ketama.continuum[continuum_index++].value= value;
 233           }
 234         }
 235         else
 236         {
 237           uint32_t value= hashkit_digest(&ptr->distribution_hashkit, sort_host, (size_t)sort_host_length);
 238           ptr->ketama.continuum[continuum_index].index= host_index;
 239           ptr->ketama.continuum[continuum_index++].value= value;
 240         }
 241       }
 242     }
 243     else
 244     {
 245       for (uint32_t pointer_index= 1;
 246            pointer_index <= pointer_per_server / pointer_per_hash;
 247            pointer_index++)
 248       {
 249         char sort_host[MEMCACHED_MAX_HOST_SORT_LENGTH]= "";
 250         int sort_host_length;
 251
 252         if (list[host_index].port == MEMCACHED_DEFAULT_PORT)
 253         {
 254           sort_host_length= snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH,
 255                                      "%s-%u",
 256                                      list[host_index].hostname,
 257                                      pointer_index - 1);
 258         }
 259         else
 260         {
 261           sort_host_length= snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH,
 262                                      "%s:%u-%u",
 263                                      list[host_index].hostname,
 264                                      (uint32_t)list[host_index].port,
 265                                      pointer_index - 1);
 266         }
 267
 268         if (sort_host_length >= MEMCACHED_MAX_HOST_SORT_LENGTH || sort_host_length < 0)
 269         {
 270           return MEMCACHED_FAILURE;
 271         }
 272
 273         WATCHPOINT_ASSERT(sort_host_length);
 274
 275         if (is_ketama_weighted)
 276         {
 277           for (uint32_t x = 0; x < pointer_per_hash; x++)
 278           {
 279              uint32_t value= ketama_server_hash(sort_host, (size_t)sort_host_length, x);
 280              ptr->ketama.continuum[continuum_index].index= host_index;
 281              ptr->ketama.continuum[continuum_index++].value= value;
 282           }
 283         }
 284         else
 285         {
 286           uint32_t value= hashkit_digest(&ptr->distribution_hashkit, sort_host, (size_t)sort_host_length);
 287           ptr->ketama.continuum[continuum_index].index= host_index;
 288           ptr->ketama.continuum[continuum_index++].value= value;
 289         }
 290       }
 291     }
 292
 293     pointer_counter+= pointer_per_server;
 294   }
 295
 296   WATCHPOINT_ASSERT(ptr);
 297   WATCHPOINT_ASSERT(ptr->continuum);
 298   WATCHPOINT_ASSERT(memcached_server_count(ptr) * MEMCACHED_POINTS_PER_SERVER <= MEMCACHED_CONTINUUM_SIZE);
 299   ptr->ketama.continuum_points_counter= pointer_counter;
 300   qsort(ptr->ketama.continuum, ptr->ketama.continuum_points_counter, sizeof(memcached_continuum_item_st), continuum_item_cmp);
 301
 302 #ifdef DEBUG
 303   for (uint32_t pointer_index= 0; memcached_server_count(ptr) && pointer_index < ((live_servers * MEMCACHED_POINTS_PER_SERVER) - 1); pointer_index++)
 304   {
 305     WATCHPOINT_ASSERT(ptr->continuum[pointer_index].value <= ptr->continuum[pointer_index + 1].value);
 306   }
 307 #endif
 308
 309   return MEMCACHED_SUCCESS;
 310 }
 311
 312
 313 memcached_return_t memcached_server_push(memcached_st *ptr, const memcached_server_list_st list)
 314 {
 315   uint32_t count;
 316   memcached_server_st *new_host_list;
 317
 318   if (! list)
 319     return MEMCACHED_SUCCESS;
 320
 321   count= memcached_server_list_count(list);
 322   new_host_list= libmemcached_realloc(ptr, memcached_server_list(ptr),
 323                                       sizeof(memcached_server_st) * (count + memcached_server_count(ptr)));
 324
 325   if (! new_host_list)
 326     return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 327
 328   memcached_server_list_set(ptr, new_host_list);
 329
 330   for (uint32_t x= 0; x < count; x++)
 331   {
 332     memcached_server_write_instance_st instance;
 333
 334     if ((ptr->flags.use_udp && list[x].type != MEMCACHED_CONNECTION_UDP)
 335             || ((list[x].type == MEMCACHED_CONNECTION_UDP)
 336             && ! (ptr->flags.use_udp)) )
 337     {
 338       return MEMCACHED_INVALID_HOST_PROTOCOL;
 339     }
 340
 341     WATCHPOINT_ASSERT(list[x].hostname[0] != 0);
 342
 343     instance= memcached_server_instance_fetch(ptr, memcached_server_count(ptr));
 344
 345     /* TODO check return type */
 346     (void)memcached_server_create_with(ptr, instance, list[x].hostname,
 347                                        list[x].port, list[x].weight, list[x].type);
 348     ptr->number_of_hosts++;
 349   }
 350
 351   // Provides backwards compatibility with server list.
 352   {
 353     memcached_server_write_instance_st instance;
 354     instance= memcached_server_instance_fetch(ptr, 0);
 355     instance->number_of_hosts= memcached_server_count(ptr);
 356   }
 357
 358   return run_distribution(ptr);
 359 }
 360
 361 memcached_return_t memcached_server_add_unix_socket(memcached_st *ptr,
 362                                                     const char *filename)
 363 {
 364   return memcached_server_add_unix_socket_with_weight(ptr, filename, 0);
 365 }
 366
 367 memcached_return_t memcached_server_add_unix_socket_with_weight(memcached_st *ptr,
 368                                                                 const char *filename,
 369                                                                 uint32_t weight)
 370 {
 371   if (! filename)
 372     return MEMCACHED_FAILURE;
 373
 374   return server_add(ptr, filename, 0, weight, MEMCACHED_CONNECTION_UNIX_SOCKET);
 375 }
 376
 377 memcached_return_t memcached_server_add_udp(memcached_st *ptr,
 378                                             const char *hostname,
 379                                             in_port_t port)
 380 {
 381   return memcached_server_add_udp_with_weight(ptr, hostname, port, 0);
 382 }
 383
 384 memcached_return_t memcached_server_add_udp_with_weight(memcached_st *ptr,
 385                                                         const char *hostname,
 386                                                         in_port_t port,
 387                                                         uint32_t weight)
 388 {
 389   if (! port)
 390     port= MEMCACHED_DEFAULT_PORT;
 391
 392   if (! hostname)
 393     hostname= "localhost";
 394
 395   return server_add(ptr, hostname, port, weight, MEMCACHED_CONNECTION_UDP);
 396 }
 397
 398 memcached_return_t memcached_server_add(memcached_st *ptr,
 399                                         const char *hostname,
 400                                         in_port_t port)
 401 {
 402   return memcached_server_add_with_weight(ptr, hostname, port, 0);
 403 }
 404
 405 memcached_return_t memcached_server_add_with_weight(memcached_st *ptr,
 406                                                     const char *hostname,
 407                                                     in_port_t port,
 408                                                     uint32_t weight)
 409 {
 410   if (! port)
 411     port= MEMCACHED_DEFAULT_PORT;
 412
 413   if (! hostname)
 414     hostname= "localhost";
 415
 416   return server_add(ptr, hostname, port, weight, MEMCACHED_CONNECTION_TCP);
 417 }
 418
 419 static memcached_return_t server_add(memcached_st *ptr, const char *hostname,
 420                                      in_port_t port,
 421                                      uint32_t weight,
 422                                      memcached_connection_t type)
 423 {
 424   memcached_server_st *new_host_list;
 425   memcached_server_write_instance_st instance;
 426
 427   if ( (ptr->flags.use_udp && type != MEMCACHED_CONNECTION_UDP)
 428       || ( (type == MEMCACHED_CONNECTION_UDP) && (! ptr->flags.use_udp) ) )
 429     return MEMCACHED_INVALID_HOST_PROTOCOL;
 430
 431   new_host_list= libmemcached_realloc(ptr, memcached_server_list(ptr),
 432                                       sizeof(memcached_server_st) * (ptr->number_of_hosts + 1));
 433
 434   if (new_host_list == NULL)
 435     return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 436
 437   memcached_server_list_set(ptr, new_host_list);
 438
 439   /* TODO: Check return type */
 440   instance= memcached_server_instance_fetch(ptr, memcached_server_count(ptr));
 441   (void)memcached_server_create_with(ptr, instance, hostname, port, weight, type);
 442   ptr->number_of_hosts++;
 443
 444   instance= memcached_server_instance_fetch(ptr, 0);
 445   memcached_servers_set_count(instance, memcached_server_count(ptr));
 446
 447   return run_distribution(ptr);
 448 }
 449
 450 memcached_return_t memcached_server_add_parsed(memcached_st *ptr,
 451                                                const char *hostname,
 452                                                size_t hostname_length,
 453                                                in_port_t port,
 454                                                uint32_t weight)
 455 {
 456   char buffer[NI_MAXHOST];
 457
 458   memcpy(buffer, hostname, hostname_length);
 459   buffer[hostname_length]= 0;
 460
 461   return server_add(ptr, buffer,
 462                     port,
 463                     weight,
 464                     MEMCACHED_CONNECTION_TCP);
 465 }