On May 15, 2006, at 11:03 PM, Jesus Cea wrote:

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> Durus release 3.4 adds support for Unix domain sockets. That is very
> nice, since we now can do access control over Durus storage server.
>
> There is a problem, nevertheless. A unix socket is persistent. That
> is,
> it creates a "socket" file in the filesystem. This file will persist
> even if the durus server dies or the machine is rebooted.
>
> But if the socket file exists, a durus server can't create a new
> socket
> with that name. That is, if the durus server dies (or the machine
> reboots), the socket file is left behind and no other durus server can
> be launched with that unix address. Until that file is deleted
> manually,
> of course.

>
> I would like to be able to automatize the procedure. I propose the
> following algorithm:
>
> a. Each unix socket "x" has an associated lock file "x.lock".
>
> b. Before trying to bind the unix socket, try to lock "x.lock". If the
> locking fails, then another server already owns the unix socket. Die
> gracefully.
>
> c. If we can lock the file, then no other durus server is using that
> unix socket. We can delete the unix domain socket file and "bind"
> to it
> again, without risk.
>
> PS: Yes, I know that I can delete the unix socket file while the
> machine
> is booting, but if the durus server dies and I relaunch it, I can't be
> sure I'm launching a single server. The lock ensures that only a
> single
> durus server is running, and if none is running, we will know it.
>
> PPS: Having a way to specify a file mode (umask) for the unix domain
> socket would be nice. Also owner/group, if we are running as root.
> Maybe
> a parameter to execute an arbitrary external function instead of the
> "bind" would be nice. So I could implement the procedure above without
> touching standard durus :-).

What if we just factor out a _get_listening_socket() from the serve()
method?
It seems like that would give you a reasonable path to follow to
implement
all of this.



>
> - --
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