Re: [Libguestfs] nbdkit design: varying the rate limit parameter

I'm embellishing this quite a lot, but this was an alternative proposal we discussed on IRC, originated by Pino Toscano: We'd add a "reload" callback to plugins and filters. Calling this is triggered when the server receives SIGHUP [currently ignored by the server]. The plugins and filters could treat this any way they wanted, but a suggestion would be that if they are taking configuration from a file then they would reload the information from that file. Note that nbdkit itself does not have a configuration file, and we don't really plan one, so this doesn't affect the server. Only the error filter uses an external "configuration file" (of sorts) but that's a special case so I don't think it would use this file. We'd then implement the rate filter with new parameters rate-file and connection-rate-file which would read the rate out of a file, and wire up the reload callback to re-read those files. I think we'd likely want the reload callback to serialise with all other callbacks, even for fully parallel plugins. Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com virt-df lists disk usage of guests without needing to install any software inside the virtual machine. Supports Linux and Windows. http://people.redhat.com/~rjones/virt-df/