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_MODULA:
  65     break;
  66   case MEMCACHED_DISTRIBUTION_RANDOM:
  67     srandom((uint32_t) time(NULL));
  68     break;
  69   case MEMCACHED_DISTRIBUTION_CONSISTENT_MAX:
  70   default:
  71     WATCHPOINT_ASSERT(0); /* We have added a distribution without extending the logic */
  72   }
  73
  74   return MEMCACHED_SUCCESS;
  75 }
  76
  77 static uint32_t ketama_server_hash(const char *key, size_t key_length, uint32_t alignment)
  78 {
  79   unsigned char results[16];
  80
  81   libhashkit_md5_signature((unsigned char*)key, key_length, results);
  82
  83   return ((uint32_t) (results[3 + alignment * 4] & 0xFF) << 24)
  84     | ((uint32_t) (results[2 + alignment * 4] & 0xFF) << 16)
  85     | ((uint32_t) (results[1 + alignment * 4] & 0xFF) << 8)
  86     | (results[0 + alignment * 4] & 0xFF);
  87 }
  88
  89 static int continuum_item_cmp(const void *t1, const void *t2)
  90 {
  91   memcached_continuum_item_st *ct1= (memcached_continuum_item_st *)t1;
  92   memcached_continuum_item_st *ct2= (memcached_continuum_item_st *)t2;
  93
  94   /* Why 153? Hmmm... */
  95   WATCHPOINT_ASSERT(ct1->value != 153);
  96   if (ct1->value == ct2->value)
  97     return 0;
  98   else if (ct1->value > ct2->value)
  99     return 1;
 100   else
 101     return -1;
 102 }
 103
 104 static memcached_return_t update_continuum(memcached_st *ptr)
 105 {
 106   uint32_t host_index;
 107   uint32_t continuum_index= 0;
 108   uint32_t value;
 109   memcached_server_st *list;
 110   uint32_t pointer_index;
 111   uint32_t pointer_counter= 0;
 112   uint32_t pointer_per_server= MEMCACHED_POINTS_PER_SERVER;
 113   uint32_t pointer_per_hash= 1;
 114   uint64_t total_weight= 0;
 115   uint64_t is_ketama_weighted= 0;
 116   uint64_t is_auto_ejecting= 0;
 117   uint32_t points_per_server= 0;
 118   uint32_t live_servers= 0;
 119   struct timeval now;
 120
 121   if (gettimeofday(&now, NULL) != 0)
 122   {
 123     memcached_set_errno(ptr, errno, NULL);
 124     return MEMCACHED_ERRNO;
 125   }
 126
 127   list = memcached_server_list(ptr);
 128
 129   /* count live servers (those without a retry delay set) */
 130   is_auto_ejecting= _is_auto_eject_host(ptr);
 131   if (is_auto_ejecting)
 132   {
 133     live_servers= 0;
 134     ptr->ketama.next_distribution_rebuild= 0;
 135     for (host_index= 0; host_index < memcached_server_count(ptr); ++host_index)
 136     {
 137       if (list[host_index].next_retry <= now.tv_sec)
 138         live_servers++;
 139       else
 140       {
 141         if (ptr->ketama.next_distribution_rebuild == 0 || list[host_index].next_retry < ptr->ketama.next_distribution_rebuild)
 142           ptr->ketama.next_distribution_rebuild= list[host_index].next_retry;
 143       }
 144     }
 145   }
 146   else
 147   {
 148     live_servers= memcached_server_count(ptr);
 149   }
 150
 151   is_ketama_weighted= memcached_behavior_get(ptr, MEMCACHED_BEHAVIOR_KETAMA_WEIGHTED);
 152   points_per_server= (uint32_t) (is_ketama_weighted ? MEMCACHED_POINTS_PER_SERVER_KETAMA : MEMCACHED_POINTS_PER_SERVER);
 153
 154   if (live_servers == 0)
 155     return MEMCACHED_SUCCESS;
 156
 157   if (live_servers > ptr->ketama.continuum_count)
 158   {
 159     memcached_continuum_item_st *new_ptr;
 160
 161     new_ptr= libmemcached_realloc(ptr, ptr->ketama.continuum,
 162                                   sizeof(memcached_continuum_item_st) * (live_servers + MEMCACHED_CONTINUUM_ADDITION) * points_per_server);
 163
 164     if (new_ptr == 0)
 165       return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 166
 167     ptr->ketama.continuum= new_ptr;
 168     ptr->ketama.continuum_count= live_servers + MEMCACHED_CONTINUUM_ADDITION;
 169   }
 170
 171   if (is_ketama_weighted)
 172   {
 173     for (host_index = 0; host_index < memcached_server_count(ptr); ++host_index)
 174     {
 175       if (list[host_index].weight == 0)
 176       {
 177         list[host_index].weight = 1;
 178       }
 179       if (! is_auto_ejecting || list[host_index].next_retry <= now.tv_sec)
 180         total_weight += list[host_index].weight;
 181     }
 182   }
 183
 184   for (host_index= 0; host_index < memcached_server_count(ptr); ++host_index)
 185   {
 186     if (is_auto_ejecting && list[host_index].next_retry > now.tv_sec)
 187       continue;
 188
 189     if (is_ketama_weighted)
 190     {
 191         float pct = (float)list[host_index].weight / (float)total_weight;
 192         pointer_per_server= (uint32_t) ((floorf((float) (pct * MEMCACHED_POINTS_PER_SERVER_KETAMA / 4 * (float)live_servers + 0.0000000001))) * 4);
 193         pointer_per_hash= 4;
 194 #ifdef DEBUG
 195         printf("ketama_weighted:%s|%d|%llu|%u\n",
 196                list[host_index].hostname,
 197                list[host_index].port,
 198                (unsigned long long)list[host_index].weight,
 199                pointer_per_server);
 200 #endif
 201     }
 202
 203
 204     if (ptr->distribution == MEMCACHED_DISTRIBUTION_CONSISTENT_KETAMA_SPY)
 205     {
 206       for (pointer_index= 0;
 207            pointer_index < pointer_per_server / pointer_per_hash;
 208            pointer_index++)
 209       {
 210         char sort_host[MEMCACHED_MAX_HOST_SORT_LENGTH]= "";
 211         int sort_host_length;
 212
 213         // Spymemcached ketema key format is: hostname/ip:port-index
 214         // If hostname is not available then: /ip:port-index
 215         sort_host_length= snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH,
 216                                    "/%s:%u-%u",
 217                                    list[host_index].hostname,
 218                                    (uint32_t)list[host_index].port,
 219                                    pointer_index);
 220
 221         if (sort_host_length >= MEMCACHED_MAX_HOST_SORT_LENGTH || sort_host_length < 0)
 222         {
 223           return MEMCACHED_FAILURE;
 224         }
 225 #ifdef DEBUG
 226         printf("update_continuum: key is %s\n", sort_host);
 227 #endif
 228
 229         WATCHPOINT_ASSERT(sort_host_length);
 230
 231         if (is_ketama_weighted)
 232         {
 233           for (uint32_t x= 0; x < pointer_per_hash; x++)
 234           {
 235              value= ketama_server_hash(sort_host, (size_t)sort_host_length, x);
 236              ptr->ketama.continuum[continuum_index].index= host_index;
 237              ptr->ketama.continuum[continuum_index++].value= value;
 238           }
 239         }
 240         else
 241         {
 242           value= hashkit_digest(&ptr->distribution_hashkit, sort_host, (size_t)sort_host_length);
 243           ptr->ketama.continuum[continuum_index].index= host_index;
 244           ptr->ketama.continuum[continuum_index++].value= value;
 245         }
 246       }
 247     }
 248     else
 249     {
 250       for (pointer_index= 1;
 251            pointer_index <= pointer_per_server / pointer_per_hash;
 252            pointer_index++)
 253       {
 254         char sort_host[MEMCACHED_MAX_HOST_SORT_LENGTH]= "";
 255         int sort_host_length;
 256
 257         if (list[host_index].port == MEMCACHED_DEFAULT_PORT)
 258         {
 259           sort_host_length= snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH,
 260                                      "%s-%u",
 261                                      list[host_index].hostname,
 262                                      pointer_index - 1);
 263         }
 264         else
 265         {
 266           sort_host_length= snprintf(sort_host, MEMCACHED_MAX_HOST_SORT_LENGTH,
 267                                      "%s:%u-%u",
 268                                      list[host_index].hostname,
 269                                      (uint32_t)list[host_index].port,
 270                                      pointer_index - 1);
 271         }
 272
 273         if (sort_host_length >= MEMCACHED_MAX_HOST_SORT_LENGTH || sort_host_length < 0)
 274         {
 275           return MEMCACHED_FAILURE;
 276         }
 277
 278         WATCHPOINT_ASSERT(sort_host_length);
 279
 280         if (is_ketama_weighted)
 281         {
 282           for (uint32_t x = 0; x < pointer_per_hash; x++)
 283           {
 284              value= ketama_server_hash(sort_host, (size_t)sort_host_length, x);
 285              ptr->ketama.continuum[continuum_index].index= host_index;
 286              ptr->ketama.continuum[continuum_index++].value= value;
 287           }
 288         }
 289         else
 290         {
 291           value= hashkit_digest(&ptr->distribution_hashkit, sort_host, (size_t)sort_host_length);
 292           ptr->ketama.continuum[continuum_index].index= host_index;
 293           ptr->ketama.continuum[continuum_index++].value= value;
 294         }
 295       }
 296     }
 297
 298     pointer_counter+= pointer_per_server;
 299   }
 300
 301   WATCHPOINT_ASSERT(ptr);
 302   WATCHPOINT_ASSERT(ptr->continuum);
 303   WATCHPOINT_ASSERT(memcached_server_count(ptr) * MEMCACHED_POINTS_PER_SERVER <= MEMCACHED_CONTINUUM_SIZE);
 304   ptr->ketama.continuum_points_counter= pointer_counter;
 305   qsort(ptr->ketama.continuum, ptr->ketama.continuum_points_counter, sizeof(memcached_continuum_item_st), continuum_item_cmp);
 306
 307 #ifdef DEBUG
 308   for (pointer_index= 0; memcached_server_count(ptr) && pointer_index < ((live_servers * MEMCACHED_POINTS_PER_SERVER) - 1); pointer_index++)
 309   {
 310     WATCHPOINT_ASSERT(ptr->continuum[pointer_index].value <= ptr->continuum[pointer_index + 1].value);
 311   }
 312 #endif
 313
 314   return MEMCACHED_SUCCESS;
 315 }
 316
 317
 318 memcached_return_t memcached_server_push(memcached_st *ptr, const memcached_server_list_st list)
 319 {
 320   uint32_t count;
 321   memcached_server_st *new_host_list;
 322
 323   if (! list)
 324     return MEMCACHED_SUCCESS;
 325
 326   count= memcached_server_list_count(list);
 327   new_host_list= libmemcached_realloc(ptr, memcached_server_list(ptr),
 328                                       sizeof(memcached_server_st) * (count + memcached_server_count(ptr)));
 329
 330   if (! new_host_list)
 331     return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 332
 333   memcached_server_list_set(ptr, new_host_list);
 334
 335   for (uint32_t x= 0; x < count; x++)
 336   {
 337     memcached_server_write_instance_st instance;
 338
 339     if ((ptr->flags.use_udp && list[x].type != MEMCACHED_CONNECTION_UDP)
 340             || ((list[x].type == MEMCACHED_CONNECTION_UDP)
 341             && ! (ptr->flags.use_udp)) )
 342     {
 343       return MEMCACHED_INVALID_HOST_PROTOCOL;
 344     }
 345
 346     WATCHPOINT_ASSERT(list[x].hostname[0] != 0);
 347
 348     instance= memcached_server_instance_fetch(ptr, memcached_server_count(ptr));
 349
 350     /* TODO check return type */
 351     (void)memcached_server_create_with(ptr, instance, list[x].hostname,
 352                                        list[x].port, list[x].weight, list[x].type);
 353     ptr->number_of_hosts++;
 354   }
 355
 356   // Provides backwards compatibility with server list.
 357   {
 358     memcached_server_write_instance_st instance;
 359     instance= memcached_server_instance_fetch(ptr, 0);
 360     instance->number_of_hosts= memcached_server_count(ptr);
 361   }
 362
 363   return run_distribution(ptr);
 364 }
 365
 366 memcached_return_t memcached_server_add_unix_socket(memcached_st *ptr,
 367                                                     const char *filename)
 368 {
 369   return memcached_server_add_unix_socket_with_weight(ptr, filename, 0);
 370 }
 371
 372 memcached_return_t memcached_server_add_unix_socket_with_weight(memcached_st *ptr,
 373                                                                 const char *filename,
 374                                                                 uint32_t weight)
 375 {
 376   if (! filename)
 377     return MEMCACHED_FAILURE;
 378
 379   return server_add(ptr, filename, 0, weight, MEMCACHED_CONNECTION_UNIX_SOCKET);
 380 }
 381
 382 memcached_return_t memcached_server_add_udp(memcached_st *ptr,
 383                                             const char *hostname,
 384                                             in_port_t port)
 385 {
 386   return memcached_server_add_udp_with_weight(ptr, hostname, port, 0);
 387 }
 388
 389 memcached_return_t memcached_server_add_udp_with_weight(memcached_st *ptr,
 390                                                         const char *hostname,
 391                                                         in_port_t port,
 392                                                         uint32_t weight)
 393 {
 394   if (! port)
 395     port= MEMCACHED_DEFAULT_PORT;
 396
 397   if (! hostname)
 398     hostname= "localhost";
 399
 400   return server_add(ptr, hostname, port, weight, MEMCACHED_CONNECTION_UDP);
 401 }
 402
 403 memcached_return_t memcached_server_add(memcached_st *ptr,
 404                                         const char *hostname,
 405                                         in_port_t port)
 406 {
 407   return memcached_server_add_with_weight(ptr, hostname, port, 0);
 408 }
 409
 410 memcached_return_t memcached_server_add_with_weight(memcached_st *ptr,
 411                                                     const char *hostname,
 412                                                     in_port_t port,
 413                                                     uint32_t weight)
 414 {
 415   if (! port)
 416     port= MEMCACHED_DEFAULT_PORT;
 417
 418   if (! hostname)
 419     hostname= "localhost";
 420
 421   return server_add(ptr, hostname, port, weight, MEMCACHED_CONNECTION_TCP);
 422 }
 423
 424 static memcached_return_t server_add(memcached_st *ptr, const char *hostname,
 425                                      in_port_t port,
 426                                      uint32_t weight,
 427                                      memcached_connection_t type)
 428 {
 429   memcached_server_st *new_host_list;
 430   memcached_server_write_instance_st instance;
 431
 432   if ( (ptr->flags.use_udp && type != MEMCACHED_CONNECTION_UDP)
 433       || ( (type == MEMCACHED_CONNECTION_UDP) && (! ptr->flags.use_udp) ) )
 434     return MEMCACHED_INVALID_HOST_PROTOCOL;
 435
 436   new_host_list= libmemcached_realloc(ptr, memcached_server_list(ptr),
 437                                       sizeof(memcached_server_st) * (ptr->number_of_hosts + 1));
 438
 439   if (new_host_list == NULL)
 440     return MEMCACHED_MEMORY_ALLOCATION_FAILURE;
 441
 442   memcached_server_list_set(ptr, new_host_list);
 443
 444   /* TODO: Check return type */
 445   instance= memcached_server_instance_fetch(ptr, memcached_server_count(ptr));
 446   (void)memcached_server_create_with(ptr, instance, hostname, port, weight, type);
 447   ptr->number_of_hosts++;
 448
 449   instance= memcached_server_instance_fetch(ptr, 0);
 450   memcached_servers_set_count(instance, memcached_server_count(ptr));
 451
 452   return run_distribution(ptr);
 453 }
 454
 455 memcached_return_t memcached_server_add_parsed(memcached_st *ptr,
 456                                                const char *hostname,
 457                                                size_t hostname_length,
 458                                                in_port_t port,
 459                                                uint32_t weight)
 460 {
 461   char buffer[NI_MAXHOST];
 462
 463   memcpy(buffer, hostname, hostname_length);
 464   buffer[hostname_length]= 0;
 465
 466   return server_add(ptr, buffer,
 467                     port,
 468                     weight,
 469                     MEMCACHED_CONNECTION_TCP);
 470 }