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plugins/mod_cron.lua @ 11986:3d5135e8a2a7

mod_cron: Initial commit of periodic task runner A number of modules now have periodic tasks that need to run, e.g. for cleaning out old messages or files. This has highlighted a need for coordinating and optimizing scheduling of such tasks.
author Kim Alvefur <zash@zash.se>
date Sun, 21 Nov 2021 15:50:36 +0100
child 11995:bbd3ac65640d
comparison
equal deleted inserted replaced
11985:3740cf7a66a3 11986:3d5135e8a2a7
1 module:set_global();
2
3 local async = require("util.async");
4
5 local periods = { hourly = 3600; daily = 86400 }
6
7 local active_hosts = {}
8
9 function module.add_host(host_module)
10
11 local last_run_times = host_module:open_store("cron", "map");
12 active_hosts[host_module.host] = true;
13
14 local function save_task(task, started_at) last_run_times:set(nil, task.id, started_at); end
15
16 local function task_added(event)
17 local task = event.item;
18 if task.name == nil then task.name = task.when; end
19 if task.id == nil then task.id = event.source.name .. "/" .. task.name:gsub("%W", "_"):lower(); end
20 if task.last == nil then task.last = last_run_times:get(nil, task.id); end
21 task.save = save_task;
22 module:log("debug", "%s task %s added, last run %s", task.when, task.id,
23 task.last and require("util.datetime").datetime(task.last) or "never");
24 return true
25 end
26
27 local function task_removed(event)
28 local task = event.item;
29 host_module:log("debug", "Task %s removed", task.id);
30 return true
31 end
32
33 host_module:handle_items("task", task_added, task_removed, true);
34
35 function host_module.unload() active_hosts[host_module.host] = nil; end
36 end
37
38 local function should_run(when, last) return not last or last + periods[when] <= os.time() end
39
40 local function run_task(task)
41 local started_at = os.time();
42 task:run(started_at);
43 task:save(started_at);
44 end
45
46 local task_runner = async.runner(run_task);
47 module:add_timer(1, function()
48 module:log("info", "Running periodic tasks");
49 local delay = 3600;
50 for host in pairs(active_hosts) do
51 module:log("debug", "Running periodic tasks for host %s", host);
52 for _, task in ipairs(module:context(host):get_host_items("task")) do
53 module:log("debug", "Considering %s task %s (%s)", task.when, task.id, task.run);
54 if should_run(task.when, task.last) then task_runner:run(task); end
55 end
56 end
57 module:log("debug", "Wait %ds", delay);
58 return delay
59 end);