git.m6w6.name Git - m6w6/libmemcached/blob - libmemcached/dump.cc

   1 /*  vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
   2  *
   3  *  Libmemcached library
   4  *
   5  *  Copyright (C) 2011 Data Differential, http://datadifferential.com/
   6  *
   7  *  Redistribution and use in source and binary forms, with or without
   8  *  modification, are permitted provided that the following conditions are
   9  *  met:
  10  *
  11  *      * Redistributions of source code must retain the above copyright
  12  *  notice, this list of conditions and the following disclaimer.
  13  *
  14  *      * Redistributions in binary form must reproduce the above
  15  *  copyright notice, this list of conditions and the following disclaimer
  16  *  in the documentation and/or other materials provided with the
  17  *  distribution.
  18  *
  19  *      * The names of its contributors may not be used to endorse or
  20  *  promote products derived from this software without specific prior
  21  *  written permission.
  22  *
  23  *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  24  *  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  25  *  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  26  *  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  27  *  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  28  *  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  29  *  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  30  *  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  31  *  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  32  *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  33  *  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  34  *
  35  */
  36
  37 /*
  38   We use this to dump all keys.
  39
  40   At this point we only support a callback method. This could be optimized by first
  41   calling items and finding active slabs. For the moment though we just loop through
  42   all slabs on servers and "grab" the keys.
  43 */
  44
  45 #include <libmemcached/common.h>
  46
  47 static memcached_return_t ascii_dump(memcached_st *memc, memcached_dump_fn *callback, void *context, uint32_t number_of_callbacks)
  48 {
  49   /* MAX_NUMBER_OF_SLAB_CLASSES is defined to 200 in Memcached 1.4.10 */
  50   for (uint32_t x= 0; x < 200; x++)
  51   {
  52     char buffer[MEMCACHED_DEFAULT_COMMAND_SIZE];
  53     int buffer_length= snprintf(buffer, sizeof(buffer), "%u", x);
  54     if (size_t(buffer_length) >= sizeof(buffer) or buffer_length < 0)
  55     {
  56       return memcached_set_error(*memc, MEMCACHED_MEMORY_ALLOCATION_FAILURE, MEMCACHED_AT,
  57                                  memcached_literal_param("snprintf(MEMCACHED_DEFAULT_COMMAND_SIZE)"));
  58     }
  59
  60     // @NOTE the hard coded zero means "no limit"
  61     libmemcached_io_vector_st vector[]=
  62     {
  63       { memcached_literal_param("stats cachedump ") },
  64       { buffer, size_t(buffer_length) },
  65       { memcached_literal_param(" 0\r\n") }
  66     };
  67
  68     // Send message to all servers
  69     for (uint32_t server_key= 0; server_key < memcached_server_count(memc); server_key++)
  70     {
  71       memcached_server_write_instance_st instance= memcached_server_instance_fetch(memc, server_key);
  72
  73       memcached_return_t vdo_rc;
  74       if (memcached_success((vdo_rc= memcached_vdo(instance, vector, 3, true))))
  75       {
  76         // We have sent the message to the server successfully
  77       }
  78       else
  79       {
  80         return vdo_rc;
  81       }
  82     }
  83
  84     // Collect the returned items
  85     memcached_server_write_instance_st instance;
  86     while ((instance= memcached_io_get_readable_server(memc)))
  87     {
  88       memcached_return_t response_rc= memcached_response(instance, buffer, MEMCACHED_DEFAULT_COMMAND_SIZE, NULL);
  89       if (response_rc == MEMCACHED_ITEM)
  90       {
  91         char *string_ptr, *end_ptr;
  92
  93         string_ptr= buffer;
  94         string_ptr+= 5; /* Move past ITEM */
  95
  96         for (end_ptr= string_ptr; isgraph(*end_ptr); end_ptr++) {} ;
  97
  98         char *key= string_ptr;
  99         key[(size_t)(end_ptr-string_ptr)]= 0;
 100
 101         for (uint32_t callback_counter= 0; callback_counter < number_of_callbacks; callback_counter++)
 102         {
 103           memcached_return_t callback_rc= (*callback[callback_counter])(memc, key, (size_t)(end_ptr-string_ptr), context);
 104           if (callback_rc != MEMCACHED_SUCCESS)
 105           {
 106             // @todo build up a message for the error from the value
 107             memcached_set_error(*instance, callback_rc, MEMCACHED_AT);
 108             break;
 109           }
 110         }
 111       }
 112       else if (response_rc == MEMCACHED_END)
 113       {
 114         // All items have been returned
 115       }
 116       else if (response_rc == MEMCACHED_SERVER_ERROR or response_rc == MEMCACHED_CLIENT_ERROR or response_rc == MEMCACHED_ERROR)
 117       {
 118         /* If we try to request stats cachedump for a slab class that is too big
 119          * the server will return an incorrect error message:
 120          * "MEMCACHED_SERVER_ERROR failed to allocate memory"
 121          * This isn't really a fatal error, so let's just skip it. I want to
 122          * fix the return value from the memcached server to a CLIENT_ERROR,
 123          * so let's add support for that as well right now.
 124        */
 125         assert(response_rc == MEMCACHED_SUCCESS); // Just fail
 126         return response_rc;
 127       }
 128       else
 129       {
 130         // IO error of some sort must have occurred
 131         return response_rc;
 132       }
 133     }
 134   }
 135
 136   return memcached_has_current_error(*memc) ? MEMCACHED_SOME_ERRORS : MEMCACHED_SUCCESS;
 137 }
 138
 139 memcached_return_t memcached_dump(memcached_st *ptr, memcached_dump_fn *callback, void *context, uint32_t number_of_callbacks)
 140 {
 141   memcached_return_t rc;
 142   if (memcached_failed(rc= initialize_query(ptr, true)))
 143   {
 144     return rc;
 145   }
 146
 147   /*
 148     No support for Binary protocol yet
 149     @todo Fix this so that we just flush, switch to ascii, and then go back to binary.
 150   */
 151   if (memcached_is_binary(ptr))
 152   {
 153     return memcached_set_error(*ptr, MEMCACHED_NOT_SUPPORTED, MEMCACHED_AT, memcached_literal_param("Binary protocol is not supported for memcached_dump()"));
 154   }
 155
 156   return ascii_dump(ptr, callback, context, number_of_callbacks);
 157 }