I use a database table for the queue. No file locking issues, atomic
transactions, you can sort and order the jobs, etc . . . you can wrap the
entire "queue" library in a module. Plus, the background script that
processes the queue can easily run with higher permissions, and you don't
have to worry as much with setuid issues when forking from a parent
process (like your apache) running as a user with less priviledges than
what you (may) need. You can pass all the args you need to via a column in
the db, and, if passing data back and forth is a must, serialize your data
using Storable and have the queue runner thaw it back out. Very simple,
very fast, very powerful.
On Wed, 4 Oct 2000, Neil Conway wrote:
> On Wed, Oct 04, 2000 at 02:42:50PM -0700, David E. Wheeler wrote:
> > Yeah, I was thinking something along these lines. Don't know if I need
> > something as complex as IPC. I was thinking of perhaps a second Apache
> > server set up just to handle long-term processing. Then the first server
> > could send a request to the second with the commands it needs to execute
> > in a header. The second server processes those commands independantly of
> > the first server, which then returns data to the browser.
>
> In a pinch, I'd just use something like a 'queue' directory. In other
> words, when your mod_perl code gets some info to process, it writes
> this into a file in a certain directory (name it with a timestamp /
> cksum to ensure the filename is unique). Every X seconds, have a
> daemon poll the directory; if it finds a file, it processes it.
> If not, it goes back to sleep for X seconds. I guess it's poor
> man's IPC. But it runs over NFS nicely, it's *very* simple, it's
> portable, and I've never needed anything more complex. You also
> don't need to fork the daemon or startup a new script every
> processing request. But if you need to do the processing in realtime,
> waiting up to X seconds for the results might be unacceptable.
>
> How does this sound?
>
> HTH,
>
> Neil
>
> --
> Neil Conway <[EMAIL PROTECTED]>
> Get my GnuPG key from: http://klamath.dyndns.org/mykey.asc
> Encrypted mail welcomed
>
> It is dangerous to be right when the government is wrong.
> -- Voltaire
>
