mod_measure_modules: Report module statuses via OpenMetrics Someone in the chat asked about a health check endpoint, which reminded me of mod_http_status, which provides access to module statuses with full details. After that, this idea came about, which seems natural. As noted in the README, it could be used to monitor that critical modules are in fact loaded correctly. As more modules use the status API, the more useful this module and mod_http_status becomes.

module:set_global()

local custom_metric = require "core.statsmanager".metric
local gc_bytes = custom_metric(
	"gauge", "lua_heap", "bytes",
	"Memory used by objects under control of the Lua garbage collector"
):with_labels()

module:hook("stats-update", function ()
	local kbytes = collectgarbage("count");
  gc_bytes:set(kbytes * 1024);
end);

custom_metric("gauge", "lua_info", "", "Lua runtime version", { "version" }):with_labels(_VERSION):set(1);