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-rw-r--r--teal-src/plugins/mod_cron.tl105
1 files changed, 105 insertions, 0 deletions
diff --git a/teal-src/plugins/mod_cron.tl b/teal-src/plugins/mod_cron.tl
new file mode 100644
index 00000000..1375a195
--- /dev/null
+++ b/teal-src/plugins/mod_cron.tl
@@ -0,0 +1,105 @@
+module:set_global();
+
+local async = require "util.async";
+local datetime = require "util.datetime";
+
+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
+ 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<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 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