OK, I just realized I can't attach files to postings. So, until I figure out what am I not seeing in the google groups interface, the patch can be downloaded from http://www.atombiztos.hu/cron-2009-01-08.patch
On Jan 8, 5:40 pm, achipa <[email protected]> wrote: > The long discussed (and maybe) awaited cron patch is here. Here's a > transcript which should make it more cloear how works ands what's it > good for. If you have any questions, or if you notice something I > messed up, please let me know. > > ====== > This does a couple of interesting things. It can dispatch things to be > executed after the client is > gone, and in a programmable way (it's in a not pretty yet, but in a > works-as-intended phase). You can put this into a controller > > class dummy(gluon.contrib.wsgihooks.PostConnectionTask): > def run(self): > logging.warning("hello") > from time import sleep > sleep(10) > logging.warning(self.env) > logging.warning("world") > > def mycontrollerfunc(): > gluon.contrib.wsgihooks.localposttasks.append(dummy(request)) > > Localposttasks are those that get executed once and are then > discarded, > globalposttasks are those that should be executed after each > connection. > Maybe it would make sense to wrap this nicely into a T2 feature. > Someone with more time and python skills could make this work as > decorators, which should be a bit cleaner. > > ======== > > Cron patch. Simplified it a bit. The postconnection part works as did > previously, the cron works more like a regular crontab. It looks for > an > applications/[application]/cron/crontab file which is in regular > crontab > format. Three modes of operation are available: > > - softcron: cron routines are checked after page content has been > served, does > not guarantee execution precision. For unprivileged apache CGI/WSGI > installs. > > - hardcron: a cron thread gets started on web2py startup. For windows > and > cherrypy/standalone installs. > > - extcron: cron functions get force-called from the command line, > usually from > the system crontab. For unix systems and places where the cron > triggers need > to be executed even if web2py is not running at the moment. Also good > for > CGI/WSGI installs if we have access to the system crontab. > > ====== > > > 1) you do you modify wsgihandler? Do I get the cron only if I use > > this handler? > > Yes (it is modified) and no (you get it also with cherrypy). > wsgihandler gives > you softcron by default. Either way (cherrypy or wsgi), can opt for > extcron > if you have system crontab access (nice, but not required). I might > have > forgotten to patch the fastcgi handler, will check that (I don't have > a > fastcgi setup at hand). > > > 2) your cron jobs are executed in threads. Will the web server kill > > them if they exceed max time? > > Hardcron (cherrypy handler) and extcron no, WSGI/fastcgi softcron also > no > (with the exception of having the webserver or the wsgi/fastcgi task > restarted itself). The only execution combination that is limited by > webserver max time should be plain CGI. We *could* implement a > maxtime > checking of our own to avoid zombie threads accumulating for bad cron > tasks > (you don't have that with regular cron either, so not sure about > that). > > > 3) If we have multiple web2py installations, only one process should > > run the hardcron. Am I wrong? How is this handled? > > All types of cron check for admin/cron/cron.master dates. Only the > instance > that manages to modify cron.master will execute the cron check cycle. > However, your question made made me wonder that you might want a > 'disable > cron' parameter in web2py to make sure all cron tasks are started by > the same > instance. > > > 4) the soft crons, in which environment are they executed, do they > > see request, response, session, etc? > > No, they are executed completely outside web2py by the wsgi callback > function > (=they are executed in the wsgi/cgi environment, but without the > ability to > return a response to user as the connection has already been closed). > > > 5) It is important that no reference to SQLDB objects is passed to > > the cron threads or this may break web2py. It looks like you are fine > > but can you confirm? > > Confirmed. Cron threads by default do not use anything from gluon. For > cases > where you DO need the DAL or gluon functionality, the cron actually > creates/invokes a new web2py environment and runs the controller/task > there > (so it gets it's own connection, objects, etc). --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "web2py Web Framework" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/web2py?hl=en -~----------~----~----~----~------~----~------~--~---
