module:set_global(); local async = require "util.async"; local datetime = require "util.datetime"; local record map_store -- TODO move to somewhere sensible get : function (map_store, string, K) : V set : function (map_store, string, K, V) end local enum frequency "hourly" "daily" "weekly" end local record task_spec id : string -- unique id name : string -- name or short description when : frequency last : integer run : function (task_spec, integer) save : function (task_spec, integer) end local record task_event source : module item : task_spec end local periods : { frequency : integer } = { hourly = 3600, daily = 86400, weekly = 7*86400 } local active_hosts : { string : boolean } = { } function module.add_host(host_module : moduleapi) local last_run_times = host_module:open_store("cron", "map") as map_store; active_hosts[host_module.host] = true; local function save_task(task : task_spec, started_at : integer) last_run_times:set(nil, task.id, started_at); end local function task_added(event : task_event) : boolean local task = event.item; if task.name == nil then task.name = task.when; end if task.id == nil then task.id = event.source.name .. "/" .. task.name:gsub("%W", "_"):lower(); end if task.last == nil then task.last = last_run_times:get(nil, task.id); end task.save = save_task; module:log("debug", "%s task %s added, last run %s", task.when, task.id, task.last and datetime.datetime(task.last) or "never"); if task.last == nil then -- initialize new tasks so e.g. daily tasks run at ~midnight UTC for now local now = os.time(); task.last = now - now % periods[task.when]; end return true; end local function task_removed(event : task_event) : boolean local task = event.item; host_module:log("debug", "Task %s removed", task.id); return true; end host_module:handle_items("task", task_added, task_removed, true); function host_module.unload() active_hosts[host_module.host]=nil; end end local function should_run(when : frequency, last : integer) : boolean return not last or last + periods[when]*0.995 <= os.time(); end local function run_task(task : task_spec) local started_at = os.time(); task:run(started_at); task:save(started_at); end local task_runner = async.runner(run_task); module:add_timer(1, function() : integer module:log("info", "Running periodic tasks"); local delay = 3600; for host in pairs(active_hosts) do module:log("debug", "Running periodic tasks for host %s", host); for _, task in ipairs(module:context(host):get_host_items("task") as { task_spec } ) do module:log("debug", "Considering %s task %s (%s)", task.when, task.id, task.run); if should_run(task.when, task.last) then task_runner:run(task); end end end module:log("debug", "Wait %ds", delay); return delay; end); -- TODO measure load, pick a good time to do stuff