On Sat, 17 Mar 2012 18:17:10 -0400 Lee Clemens <j...@leeclemens.net> wrote:
> On 03/16/2012 11:37 PM, John O'Hagan wrote: > > On Fri, 16 Mar 2012 22:12:14 -0400 > > Lee Clemens <j...@leeclemens.net> wrote: > > > >> I have a multi-threaded application > >> > >> I have provided a test-case here: https://gist.github.com/2054194 > > I haven't looked at your test case yet, but a possible cause is the fact > > that the main application (or main thread) exits if it has finished > > executing and only daemon threads remain. This can abruptly terminate > > threads which may be busy, for example, communicating via a pipe. The best > > solution IMO is not to use daemon threads, but to give all threads a way to > > terminate cleanly before the main thread does, even if this means using a > > flag or the like. > > > > HTH, > > > > John > > > I call .join() on each spawned thread, whether it is daemonized or not. > The code is available here: > > https://gist.github.com/2054194 I've tried running your code (which at a glance looks very well-written) but I get the broken pipe errors whether the DAEMONIZE flag is True or False (Python 2.7, Debian testing). I don't have time to dig much deeper. > Is it generally not recommended to daemonize Python applications using > this method? I'm no guru, but not that I know of. I haven't seen the os.fork method you use before; out of interest, why not use Thread.setDaemon? > Do you have any references or data to support your opinion? > Do you have any references which specifically state - "Daemonizing > Python applications cause Python to work in unexpected ways."? Not particularly, although there are a few oldish references to "Python daemon threads considered harmful" out there. You probably know that daemonising can cover a multitude of sins, and it's always a good idea to ensure clean termination and not just assume that what happens in a daemon thread on program exit is moot. I'm not saying you haven't done that, in fact your errors seem to occur during execution, not termination. I replied to your post because I've had broken pipe errors before with daemon threads communicating on sockets which sounded similar to your issue. I solved them by rewriting so that the main thread told the threads to terminate, and waited till they had. This made daemonising unnecessary in that case. [...] Regards, John -- http://mail.python.org/mailman/listinfo/python-list
