[erlang-questions] What is the right way to update cowboy dispatch rules on-fly?

Loïc Hoguin <>
Mon Sep 3 21:41:18 CEST 2012

On 09/03/2012 09:34 PM, Max Lapshin wrote:
> I see the problem: you don't use undocumented call
> prim_inet:async_accept and thus you can't catch message in
> acceptor, that something has changed.
> It really cannot be changed, unless proper undocumented feature is used here =(

The code in Ranch has async accept through a documented method. So the 
protocol options upgrade is more instantaneous there (as opposed to "the 
connection after next"). Cowboy will be able to make use of that soon.

But that doesn't really change anything about currently running requests 
which still use the old options. It shouldn't give you any problem 
unless you use release upgrades and API/data changed though. Old options 
and new options can run side-by-side without issue.

I'm not sure what you are doing, especially since you said it requires 
restarting Cowboy? I'll need more details to be able to help you. What 
are you trying to do?

Loïc Hoguin
Erlang Cowboy
Nine Nines

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