--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mod_munin/mod_munin.lua	Tue Mar 10 16:39:08 2015 +0100
@@ -0,0 +1,123 @@
+module:set_global();
+
+local s_format = string.format;
+local array = require"util.array";
+local it = require"util.iterators";
+local mt = require"util.multitable";
+local set = require"util.set";
+
+local meta = mt.new(); meta.data = module:shared"meta";
+local data = mt.new(); data.data = module:shared"data";
+
+local munin_listener = {};
+local munin_commands = {};
+
+local node_name = module:get_option_string("munin_node_name", "localhost");
+local ignore_stats = module:get_option_set("munin_ignored_stats", { });
+
+local function clean_fieldname(name)
+	return (name:gsub("[^A-Za-z0-9_]", "_"):gsub("^[^A-Za-z_]", "_%1"));
+end
+
+function munin_listener.onconnect(conn)
+	-- require"core.statsmanager".collect();
+	conn:write("# munin node at "..node_name.."\n");
+end
+
+function munin_listener.onincoming(conn, line)
+	line = line and line:match("^[^\r\n]+");
+	if type(line) ~= "string" then return end
+	-- module:log("debug", "incoming: %q", line);
+	local command = line:match"^%w+";
+	command = munin_commands[command];
+	if not command then
+		conn:write("# Unknown command.\n");
+		return;
+	end
+	local ok, err = pcall(command, conn, line);
+	if not ok then
+		module:log("error", "Error running %q: %s", line, err);
+		conn:close();
+	end
+end
+
+function munin_listener.ondisconnect() end
+
+function munin_commands.cap(conn)
+	conn:write("cap\n");
+end
+
+function munin_commands.list(conn, line)
+	conn:write(array(it.keys(data.data)):concat(" ") .. "\n");
+end
+
+function munin_commands.config(conn, line)
+	-- TODO what exactly?
+	local stat = line:match("%s(%S+)");
+	if not stat then conn:write("# Unknown service\n.\n"); return end
+	for key, name, k, value in meta:iter(stat, "", nil) do
+		conn:write(s_format("%s %s\n", k, value));
+	end
+	for key, name, k, value in meta:iter(stat, nil, nil) do
+		if name ~= "" then
+			conn:write(s_format("%s.%s %s\n", name, k, value));
+		end
+	end
+	conn:write(".\n");
+end
+
+function munin_commands.fetch(conn, line)
+	local stat = line:match("%s(%S+)");
+	if not stat then conn:write("# Unknown service\n.\n"); return end
+	for key, name, value in data:iter(stat, nil) do
+		conn:write(s_format("%s.value %s\n", name, tostring(value)));
+	end
+	conn:write(".\n");
+end
+
+function munin_commands.quit(conn)
+	conn:close();
+end
+
+module:hook("stats-updated", function (event)
+	local all_stats, this = event.stats_extra;
+	local host, sect, name, typ, key;
+	for stat, value in pairs(event.changed_stats) do
+		if not ignore_stats:contains(stat) then
+			this = all_stats[stat];
+			-- module:log("debug", "changed_stats[%q] = %s", stat, tostring(value));
+			host, sect, name, typ = stat:match("^/([^/]+)/([^/]+)/(.+):(%a+)$");
+			if host == nil then
+				sect, name, typ, host = stat:match("^([^.]+)%.([^:]+):(%a+)$");
+			elseif host == "*" then
+				host = nil;
+			end
+			key = clean_fieldname(s_format("%s_%s_%s", host or "global", sect, typ));
+
+			if not meta:get(key) then
+				if host then
+					meta:set(key, "", "graph_title", s_format("%s %s on %s", sect, typ, host));
+				else
+					meta:set(key, "", "graph_title", s_format("Global %s %s", sect, typ, host));
+				end
+				meta:set(key, "", "graph_vlabel", this and this.units or typ);
+				meta:set(key, "", "graph_category", sect);
+
+				meta:set(key, name, "label", name);
+			elseif not meta:get(key, name, "label") then
+				meta:set(key, name, "label", name);
+			end
+
+			data:set(key, name, value);
+		else
+			-- module:log("debug", "Ignoring stat %q", stat);
+		end
+	end
+end);
+
+module:provides("net", {
+	listener = munin_listener;
+	default_mode = "*l";
+	default_port = 4949;
+});
+