1 files changed, 141 insertions, 0 deletions
diff --git a/teal-src/prosody/plugins/mod_cron.tl b/teal-src/prosody/plugins/mod_cron.tl
new file mode 100644
index 00000000..4defc808
--- /dev/null
+++ b/teal-src/prosody/plugins/mod_cron.tl
@@ -0,0 +1,141 @@
+module:set_global();
+
+local async = require "prosody.util.async";
+
+local cron_initial_delay = module:get_option_number("cron_initial_delay", 1);
+local cron_check_delay = module:get_option_number("cron_check_delay", 3600);
+local cron_spread_factor = module:get_option_number("cron_spread_factor", 0);
+
+local record map_store<K,V>
+	-- TODO move to somewhere sensible
+	get : function (map_store<K,V>, string, K) : V
+	set : function (map_store<K,V>, 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
+	period : number
+	last : integer
+	run : function (task_spec, integer)
+	save : function (task_spec, integer)
+	restore : function (task_spec, integer)
+end
+
+local record task_event
+	source : module
+	item : task_spec
+end
+
+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<string,integer>;
+	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 restore_task(task : task_spec)
+		if task.last == nil then
+			task.last = last_run_times:get(nil, task.id);
+		end
+	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
+		task.period = host_module:get_option_period(task.id:gsub("/", "_") .. "_period", "1" .. task.when, 60, 86400*7*53);
+		task.restore = restore_task;
+		task.save = save_task;
+		module:log("debug", "%s task %s added", task.when, task.id);
+		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(task : task_spec, last : integer) : boolean
+	return not last or last + task.period * 0.995 <= os.time();
+end
+
+local function run_task(task : task_spec)
+	task:restore();
+	if not should_run(task, task.last) then
+		return;
+	end
+	local started_at = os.time();
+	task:run(started_at);
+	task.last = started_at;
+	task:save(started_at);
+end
+
+local function spread(t : number, factor : number) : number
+	return t * (1 - factor + 2*factor*math.random());
+end
+
+local task_runner : async.runner_t<task_spec> = async.runner(run_task);
+scheduled = module:add_timer(cron_initial_delay, function() : number
+	module:log("info", "Running periodic tasks");
+	local delay = spread(cron_check_delay, cron_spread_factor);
+	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
+			task_runner:run(task);
+		end
+	end
+	module:log("debug", "Wait %gs", delay);
+	return delay;
+end);
+
+-- TODO measure load, pick a good time to do stuff
+
+module:add_item("shell-command", {
+	section = "cron";
+	section_desc = "View and manage recurring tasks";
+	name = "tasks";
+	desc = "View registered tasks";
+	args = {};
+	handler = function (self, filter_host : string)
+		local format_table = require "prosody.util.human.io".table;
+		local it = require "util.iterators";
+		local row = format_table({
+			{ title = "Host", width = "2p" };
+			{ title = "Task", width = "3p" };
+			{ title = "Desc", width = "3p" };
+			{ title = "When", width = "1p" };
+			{ title = "Last run", width = "20" };
+		}, self.session.width);
+		local print = self.session.print;
+		print(row());
+		for host in it.sorted_pairs(filter_host and { [filter_host]=true } or active_hosts) do
+			for _, task in ipairs(module:context(host):get_host_items("task")) do
+				print(row { host, task.id, task.name, task.when, task.last and os.date("%Y-%m-%d %R:%S", task.last) or "never" });
+			end
+		end
+	end;
+});