akiatoji

-- Reimplemented coroutine.wrap, returning "nil, err" if the coroutine cannot
-- be resumed.
local co_wrap = function(func)
    local co = coroutine.create(func)
    ngx.log(ngx.DEBUG, "co created with status ", coroutine.status(co))
    return function(...)
        if coroutine.status(co) == "suspended" then
            return select(2, coroutine.resume(co, ...))
        else
            return nil, "can't resume a " .. coroutine.status(co) .. " coroutine"