author | Kim Alvefur <zash@zash.se> |
Mon, 14 Sep 2015 13:36:00 +0200 | |
changeset 1861 | 5a19ccd8457a |
parent 1492 | 8c4a2d85e8bf |
child 1593 | 3e4d15ae2133 |
permissions | -rw-r--r-- |
1492
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mod_storage_multi: Multi-backend storage module (WIP)
Kim Alvefur <zash@zash.se>
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1 |
-- mod_storage_multi |
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2 |
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3 |
local storagemanager = require"core.storagemanager"; |
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4 |
local backends = module:get_option_array(module.name); -- TODO better name? |
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5 |
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6 |
-- TODO migrate data "upwards" |
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7 |
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8 |
-- one → one successful write is success |
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9 |
-- all → all backends must report success |
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10 |
-- majority → majority of backends must report success |
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11 |
local policy = module:get_option_string(module.name.."_policy", "all"); |
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12 |
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mod_storage_multi: Multi-backend storage module (WIP)
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13 |
local keyval_store = {}; |
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keyval_store.__index = keyval_store; |
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15 |
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16 |
function keyval_store:get(username) |
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17 |
local backends = self.backends; |
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18 |
local data, err; |
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for i = 1, #backends do |
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module:log("debug", "%s:%s:get(%q)", tostring(backends[i].get), backends[i]._store, username); |
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data, err = backends[i]:get(username); |
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22 |
if err then |
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module:log("error", tostring(err)); |
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24 |
elseif not data then |
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25 |
module:log("debug", "No data returned"); |
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26 |
else |
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27 |
module:log("debug", "Data returned"); |
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28 |
return data, err; |
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29 |
end |
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30 |
end |
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31 |
end |
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33 |
-- This is where it gets complicated |
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34 |
function keyval_store:set(username, data) |
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mod_storage_multi: Multi-backend storage module (WIP)
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35 |
local backends = self.backends; |
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36 |
local ok, err, backend; |
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mod_storage_multi: Multi-backend storage module (WIP)
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local all, one, oks = true, false, 0; |
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mod_storage_multi: Multi-backend storage module (WIP)
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38 |
for i = 1, #backends do |
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mod_storage_multi: Multi-backend storage module (WIP)
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39 |
backend = backends[i]; |
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mod_storage_multi: Multi-backend storage module (WIP)
Kim Alvefur <zash@zash.se>
parents:
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40 |
module:log("debug", "%s:%s:set(%q)", tostring(backends[i].get), backends[i].store, username); |
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mod_storage_multi: Multi-backend storage module (WIP)
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41 |
ok, err = backend:set(username, data); |
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42 |
if not ok then |
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mod_storage_multi: Multi-backend storage module (WIP)
Kim Alvefur <zash@zash.se>
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module:log("error", "Error in storage driver %s: %s", backend.name, tostring(err)); |
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else |
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45 |
oks = oks + 1; |
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46 |
end |
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47 |
one = one or ok; -- At least one successful write |
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48 |
all = all and ok; -- All successful |
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49 |
end |
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50 |
if policy == "all" then |
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51 |
return all, err |
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elseif policy == "majority" then |
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return oks > (#backends/2), err; |
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end |
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-- elseif policy == "one" then |
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56 |
return one, err; |
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end |
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58 |
|
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59 |
local stores = { |
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keyval = keyval_store; |
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61 |
} |
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62 |
|
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63 |
local driver = {}; |
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64 |
|
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function driver:open(store, typ) |
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66 |
local store_mt = stores[typ or "keyval"]; |
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67 |
if store_mt then |
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68 |
local my_backends = {}; |
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local driver, opened |
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for i = 1, #backends do |
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71 |
driver = storagemanager.load_driver(module.host, backends[i]); |
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72 |
opened = driver:open(store, typ); |
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my_backends[i] = assert(driver:open(store, typ)); |
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my_backends[i]._store = store; |
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75 |
end |
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return setmetatable({ backends = my_backends }, store_mt); |
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77 |
end |
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78 |
return nil, "unsupported-store"; |
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79 |
end |
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80 |
|
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81 |
module:provides("storage", driver); |