--- a/util/async.lua	Fri Mar 16 14:51:24 2018 +0000
+++ b/util/async.lua	Fri Mar 16 14:59:41 2018 +0000
@@ -1,4 +1,5 @@
 local log = require "util.logger".init("util.async");
+local new_id = require "util.id".short;
 
 local function checkthread()
 	local thread, main = coroutine.running();
@@ -99,13 +100,14 @@
 local empty_watchers = {};
 local function runner(func, watchers, data)
 	return setmetatable({ func = func, thread = false, state = "ready", notified_state = "ready",
-		queue = {}, watchers = watchers or empty_watchers, data = data }
+		queue = {}, watchers = watchers or empty_watchers, data = data, id = new_id() }
 	, runner_mt);
 end
 
 -- Add a task item for the runner to process
 function runner_mt:run(input)
 	if input ~= nil then
+		self:log("debug", "queued new work item, %d items queued", #self.queue);
 		table.insert(self.queue, input);
 	end
 	if self.state ~= "ready" then
@@ -116,6 +118,7 @@
 
 	local q, thread = self.queue, self.thread;
 	if not thread or coroutine.status(thread) == "dead" then
+		self:log("debug", "creating new coroutine");
 		-- Create a new coroutine for this runner
 		thread = runner_create_thread(self.func, self);
 		self.thread = thread;
@@ -124,6 +127,7 @@
 	-- Process task item(s) while the queue is not empty, and we're not blocked
 	local n, state, err = #q, self.state, nil;
 	self.state = "running";
+	self:log("debug", "running main loop");
 	while n > 0 and state == "ready" do
 		local consumed;
 		-- Loop through queue items, and attempt to run them
@@ -156,6 +160,7 @@
 	-- Runner processed all items it can, so save current runner state
 	self.state = state;
 	if err or state ~= self.notified_state then
+		self:log("debug", "changed state from %s to %s", self.notified_state, err and "error" or state);
 		if err then
 			state = "error"
 		else
@@ -172,4 +177,8 @@
 	table.insert(self.queue, input);
 end
 
+function runner_mt:log(level, fmt, ...)
+	return log(level, "[runner %s] "..fmt, self.id, ...);
+end
+
 return { waiter = waiter, guarder = guarder, runner = runner };