core/storagemanager.lua

   1
   2 local error, type, pairs = error, type, pairs;
   3 local setmetatable = setmetatable;
   4
   5 local config = require "core.configmanager";
   6 local datamanager = require "util.datamanager";
   7 local modulemanager = require "core.modulemanager";
   8 local multitable = require "util.multitable";
   9 local hosts = hosts;
  10 local log = require "util.logger".init("storagemanager");
  11
  12 local prosody = prosody;
  13
  14 module("storagemanager")
  15
  16 local olddm = {}; -- maintain old datamanager, for backwards compatibility
  17 for k,v in pairs(datamanager) do olddm[k] = v; end
  18 _M.olddm = olddm;
  19
  20 local null_storage_method = function () return false, "no data storage active"; end
  21 local null_storage_driver = setmetatable(
  22         {
  23                 name = "null",
  24                 open = function (self) return self; end
  25         }, {
  26                 __index = function (self, method)
  27                         return null_storage_method;
  28                 end
  29         }
  30 );
  31
  32 local stores_available = multitable.new();
  33
  34 function initialize_host(host)
  35         local host_session = hosts[host];
  36         host_session.events.add_handler("item-added/data-driver", function (event)
  37                 local item = event.item;
  38                 stores_available:set(host, item.name, item);
  39         end);
  40
  41         host_session.events.add_handler("item-removed/data-driver", function (event)
  42                 local item = event.item;
  43                 stores_available:set(host, item.name, nil);
  44         end);
  45 end
  46 prosody.events.add_handler("host-activated", initialize_host, 101);
  47
  48 function load_driver(host, driver_name)
  49         if driver_name == "null" then
  50                 return null_storage_provider;
  51         end
  52         local driver = stores_available:get(host, driver_name);
  53         if driver then return driver; end
  54         local ok, err = modulemanager.load(host, "storage_"..driver_name);
  55         if not ok then
  56                 log("error", "Failed to load storage driver plugin %s on %s: %s", driver_name, host, err);
  57         end
  58         return stores_available:get(host, driver_name);
  59 end
  60
  61 function open(host, store, typ)
  62         local storage = config.get(host, "core", "storage");
  63         local driver_name;
  64         local option_type = type(storage);
  65         if option_type == "string" then
  66                 driver_name = storage;
  67         elseif option_type == "table" then
  68                 driver_name = storage[store];
  69         end
  70         if not driver_name then
  71                 driver_name = config.get(host, "core", "default_storage") or "internal";
  72         end
  73
  74         local driver = load_driver(host, driver_name);
  75         if not driver then
  76                 log("warn", "Falling back to null driver for %s storage on %s", store, host);
  77                 driver_name = "null";
  78                 driver = null_storage_driver;
  79         end
  80
  81         local ret, err = driver:open(store, typ);
  82         if not ret then
  83                 if err == "unsupported-store" then
  84                         log("debug", "Storage driver %s does not support store %s (%s), falling back to null driver",
  85                                 driver_name, store, typ);
  86                         ret = null_storage_driver;
  87                         err = nil;
  88                 end
  89         end
  90         return ret, err;
  91 end
  92
  93 function datamanager.load(username, host, datastore)
  94         return open(host, datastore):get(username);
  95 end
  96 function datamanager.store(username, host, datastore, data)
  97         return open(host, datastore):set(username, data);
  98 end
  99
 100 return _M;