core/storagemanager.lua

   1
   2 local error, type = error, type;
   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 olddm = {}; -- maintain old datamanager, for backwards compatibility
  13 for k,v in pairs(datamanager) do olddm[k] = v; end
  14
  15 module("storagemanager")
  16
  17 local default_driver_mt = { name = "internal" };
  18 default_driver_mt.__index = default_driver_mt;
  19 function default_driver_mt:open(store)
  20         return setmetatable({ host = self.host, store = store }, default_driver_mt);
  21 end
  22 function default_driver_mt:get(user) return olddm.load(user, self.host, self.store); end
  23 function default_driver_mt:set(user, data) return olddm.store(user, self.host, self.store, data); end
  24
  25 local stores_available = multitable.new();
  26
  27 function initialize_host(host)
  28         host_session.events.add_handler("item-added/data-driver", function (event)
  29                 local item = event.item;
  30                 stores_available:set(host, item.name, item);
  31         end);
  32
  33         host_session.events.add_handler("item-removed/data-driver", function (event)
  34                 local item = event.item;
  35                 stores_available:set(host, item.name, nil);
  36         end);
  37 end
  38
  39 local function load_driver(host, driver_name)
  40         if not driver_name then
  41                 return;
  42         end
  43         local driver = stores_available:get(host, driver_name);
  44         if not driver then
  45                 if driver_name ~= "internal" then
  46                         modulemanager.load(host, "storage_"..driver_name);
  47                         return stores_available:get(host, driver_name);
  48                 else
  49                         return setmetatable({host = host}, default_driver_mt);
  50                 end
  51         end
  52 end
  53
  54 function open(host, store, typ)
  55         local storage = config.get(host, "core", "storage");
  56         local driver_name;
  57         local option_type = type(storage);
  58         if option_type == "string" then
  59                 driver_name = storage;
  60         elseif option_type == "table" then
  61                 driver_name = storage[store];
  62         end
  63
  64         local driver = load_driver(host, driver_name);
  65         if not driver then
  66                 driver_name = config.get(host, "core", "default_storage");
  67                 driver = load_driver(host, driver_name);
  68                 if not driver then
  69                         if storage or driver_name then
  70                                 log("warn", "Falling back to default driver for %s storage on %s", store, host);
  71                         end
  72                         driver_name = "internal";
  73                         driver = load_driver(host, driver_name);
  74                 end
  75         end
  76
  77         local ret, err = driver:open(store, typ);
  78         if not ret then
  79                 if err == "unsupported-store" then
  80                         log("debug", "Storage driver %s does not support store %s (%s), falling back to internal driver",
  81                                 driver_name, store, typ);
  82                         ret = setmetatable({ host = host, store = store }, default_driver_mt); -- default to default driver
  83                         err = nil;
  84                 end
  85         end
  86         return ret, err;
  87 end
  88
  89 function datamanager.load(username, host, datastore)
  90         return open(host, datastore):get(username);
  91 end
  92 function datamanager.store(username, host, datastore, data)
  93         return open(host, datastore):set(username, data);
  94 end
  95
  96 return _M;