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mod_storage_multi/mod_storage_multi.lua @ 4877:adc6241e5d16
mod_measure_process: Report the enforced limit
The soft limit is what the kernel actually enforces, while the hard
limit is is how far you can change the soft limit without privileges.
Unless the process dynamically adjusts the soft limit, knowing the hard
limit is not as useful as knowing the soft limit.
Reporting the soft limit and the number of in-use FDs allows placing
alerts on expressions like 'process_open_fds / process_max_fds >= 0.95'
author | Kim Alvefur <zash@zash.se> |
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date | Tue, 18 Jan 2022 18:55:20 +0100 (2022-01-18) |
parent | 1492:8c4a2d85e8bf |
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-- mod_storage_multi local storagemanager = require"core.storagemanager"; local backends = module:get_option_array(module.name); -- TODO better name? -- TODO migrate data "upwards" -- one → one successful write is success -- all → all backends must report success -- majority → majority of backends must report success local policy = module:get_option_string(module.name.."_policy", "all"); local keyval_store = {}; keyval_store.__index = keyval_store; function keyval_store:get(username) local backends = self.backends; local data, err; for i = 1, #backends do module:log("debug", "%s:%s:get(%q)", tostring(backends[i].get), backends[i]._store, username); data, err = backends[i]:get(username); if err then module:log("error", tostring(err)); elseif not data then module:log("debug", "No data returned"); else module:log("debug", "Data returned"); return data, err; end end end -- This is where it gets complicated function keyval_store:set(username, data) local backends = self.backends; local ok, err, backend; local all, one, oks = true, false, 0; for i = 1, #backends do backend = backends[i]; module:log("debug", "%s:%s:set(%q)", tostring(backends[i].get), backends[i].store, username); ok, err = backend:set(username, data); if not ok then module:log("error", "Error in storage driver %s: %s", backend.name, tostring(err)); else oks = oks + 1; end one = one or ok; -- At least one successful write all = all and ok; -- All successful end if policy == "all" then return all, err elseif policy == "majority" then return oks > (#backends/2), err; end -- elseif policy == "one" then return one, err; end local stores = { keyval = keyval_store; } local driver = {}; function driver:open(store, typ) local store_mt = stores[typ or "keyval"]; if store_mt then local my_backends = {}; local driver, opened for i = 1, #backends do driver = storagemanager.load_driver(module.host, backends[i]); opened = driver:open(store, typ); my_backends[i] = assert(driver:open(store, typ)); my_backends[i]._store = store; end return setmetatable({ backends = my_backends }, store_mt); end return nil, "unsupported-store"; end module:provides("storage", driver);