I recently discovered that uWSGI has a "cheap mode" that will hold the socket open but only actually spawn workers when a connection comes in (and kill them automatically after a timeout without any requests).
If you already have 24/7 compute instances going and can spare the CPU/RAM headroom, you can co-host your "lambdas" there, and make them even cheaper :)
Pertinent options: https://github.com/piku/piku/blob/master/piku.py#L908
If you already have 24/7 compute instances going and can spare the CPU/RAM headroom, you can co-host your "lambdas" there, and make them even cheaper :)