From: Sam Duncan <sduncan@...>
Date: 2012-04-13T11:32:43+09:00
Subject: Re: Change the value of a variable inside a running ruby program.

On 13/04/12 13:38, Matthew Smith wrote:
> I have a program that is running constantly and I'd like to be able to
> change the value of a variable inside it from the outside by doing
> something on the command line.
>
> Ideally, this would happen via an interrupt process so that the program
> doesn't have to continuously poll some resource.
>
> Right now, the program just polls mysql every few seconds to see if
> someone has changed a setting which is stored in a table.  Ideally, I'd
> like the program to read from the table on startup but then not have to
> poll mysql anymore to see if the setting has been changed.
>
> Hopefully I'm making sense here...
>
Could you just use a HUP, SIGUSR1 or 2 signal handler to set the flag? 
Either it causes the app to reread the value from the database, or if it 
is just a toggle/ dual state item, simply switches it based on which 
signal it gets?

Sam