i guess i should have done a better job of explaining myself. :)
am using a very typical apache setup - yes w/ multiple processes.
picture this:
1 (or more) apache server, one (or more) physical machine.
- each spawns say 16 server processes
- each process contains one thread, named "mailer"
this means 16 mailer threads (or 32, if two machines). but i only want
one mailer thread running at a time. (to avoid sending duplicate emails
during a race condition) but apache kills and restarts processes, so i
can't just randomly pick one. all processes must collude and elect one
and only process as "it". and they need to detect when the "it" thread
has died because apache killed it's parent process, and elect a new one.
obviously the processes would have to collude through some communication
channel....networking, memcached, the db, whatever. just wondering if
such a thing exists before i roll my own, as it would seem to me to be a
relatively common programming need.
Jeremy Dunck wrote:
> I'm not sure how you're deploying, but most people use multiple
> processes rather than a single process. Given that, an in-process
> mutex will do you no good.
>
> If you really are single-process, Django does not have a built-in
> mutex, but maybe you want:
> http://docs.python.org/lib/module-mutex.html
>
>
> On 8/17/07, Derek Anderson <[EMAIL PROTECTED]> wrote:
>> no, not trying to farm out many threads. already have many threads
>> running. (from apache) and (obviously) there is no master thread to do
>> the coordination. see: http://en.wikipedia.org/wiki/Mutual_exclusion
>> just want to make sure no two threads are entering the same critical
>> section at the same time.
>>
>>
>> Jeremy Dunck wrote:
>>> I think you want gearmand:
>>> http://www.danga.com/gearman/
>>>
>>> It has a 'uniq' property that ensures only one job with a given name is
>>> running.
>>>
>>> On 8/17/07, Derek Anderson <[EMAIL PROTECTED]> wrote:
>>>> i have a number of background threads in my app, and for a few of them i
>>>> want to make sure only one of them exist. (not one per server thread)
>>>>
>>>> for instance, my bigram indexer....or my notification mailer.
>>
>
> >
>
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