Re: [web2py] cron Too many open files regression?
The code running this is in gluon/newcron.py From your stack trace you are using hard cron which is a class at line 44. It runs launch once a minute This runs crondance which puts a wrapper on the tasks that should be run adding web2py run line parameters if * or ** is at the beginning of the command. The crondance function then uses class cronlauncher which in turn uses subprocess.Popen to launch the task. If you have web2py like processes building up do these processes have other processes with the web2py process pid listed as the parent process. You should be able to do a ps -ef pick the pid of one of the web2py processes and run another ps -ef with grep pid to filter. The process started with the Popen will have to close the pipe usually by exiting to release the thread from cronlauncher. Do these cron tasks run okay if you just launch them from the shell. That is a good test to determine that there are no problems outside the cron environment. Do you use a SQLite database? This database performs a global lock to protect from multiple access. Do the cron tasks take more than their scheduling interval to complete. The launcher will run another copy without regard for an existing copy still running. Do any of the tasks have locking code such as a file lock that other tasks depend on gaining access to. Two file locks shared by two processes with crossed access, one process locks a then b, other locks b then a will deadlock if the timing is right. Do any tasks read stdin, the subprocess.Popen call opens the stdin of the process to the launcher but will never write to it so a read on stdin would hang preventing exit. I hope this is some help, looks like a difficult one to find but likely something fairly simple to fix once you find it. Could you post your crontab file, it would be a start of something to look at.
Re: [web2py] cron Too many open files regression?
None that I know of. The processes that accumulate have the same arguments as the main web2py process (as shown by ps -ef) so it's like a fork with no exec. On Wednesday, July 6, 2011, ron_m ron.mco...@gmail.com wrote: Maybe one possibility is if your code has classes with a __del__ method in them, Massimo would have better perspective on if this is a possibility. If a class with this method is involved in a circular reference the garbage collector cannot clean it up because of uncertainty of execution of the __del__ method. This was discussed a lot on the group a few months back. I believe exec also has to be involved. Do a search for __del__ in the group to see what was said. There were also some tools mentioned in those threads that help with tracking down this sort of problem. I find in Python as soon as a file variable binding produced by open goes out of scope it is closed, you don't have to specifically call close on it. Normally objects are dropped as soon as the reference count reaches 0. The garbage collector was added to clean up the circular referenced objects that will never get a count down to 0 without some outside help. It searches the heap looking for objects that have no references except other objects also in the garbage and marks those as candidates to clean out. The fact that these file objects are piling up means something is holding the file reference which also cannot be cleaned up. Are you running on Linux? If so the /proc/pid_of_web2py/fd directory using ls -l will show you what files by name are open to the process which might provide some clues to which part of your code. -- John Duddy jdu...@gmail.com
[web2py] cron Too many open files regression?
I'm getting the following stack trace in my console after leaving my app running overnight. We use cron for several tasks. I saw the below thread, which indicated that the issue has been resolved: http://groups.google.com/group/web2py/browse_thread/thread/e788b0783e8fc758/6a210abb2898763d?lnk=raot Has there been a regression? Here's the stack trace. Thanks! Traceback (most recent call last): File /usr/local/lib/python2.7/threading.py, line 552, in __bootstrap_inner self.run() File /root/web2py/gluon/newcron.py, line 63, in run s.run() File /usr/local/lib/python2.7/sched.py, line 117, in run File /root/web2py/gluon/newcron.py, line 55, in launch crondance(self.path, 'hard', startup = False) File /root/web2py/gluon/newcron.py, line 234, in crondance cronmaster = token.acquire(startup=startup) File /root/web2py/gluon/newcron.py, line 101, in acquire self.master = open(self.path,'rb+') IOError: [Errno 24] Too many open files: '/root/web2py/applications/ admin/cron/cron.master'
