Re: POE and perl fork interaction
Deven, Take a look at the Cookbook and the job control examples. While a poe kernel is a process singleton, you can have many sessions running on the same kernel. Dougie!!! -Original Message- From: Deven Parekh To: [email protected] Cc: [email protected]; [email protected] Sent: Thu, 15 Jan 2009 10:35 am Subject: Re: POE and perl fork interaction Hello Rob, Dougie, Thanks for the suggestion. I apologize for not being clear on what i am trying to achieve. Basically I have built a wrapper module around POE to handle certain tasks. This allows the user of the wrapper module to be ignorant about POE. Each task has its own wrapper module and interface. examples of task is - tailig of files, has its own set of wrapper module - placing a test VOIP call to VOIP server under test, has its own set of wrapper module - verifying contents in tailed files, has it own set of wrapper module I want each of these to be independent POE wrappers and an independent way to start/stop each of the task. I have POE::Kernel->run per set of wrapper modules that starts of the task. I tried to create a set of wrapper module for the file tailing using POE::Component::IKC POE::Wheel::FollowTail (i wanted to tail files on remote machines, so also looked at POE::Componenet::RemoteTail) POE::Wheel::Run But since POE::Kernel is a singleton per process when i have a script that is trying to launch multiple task (implying multiple sets of wrappers) there is lot of interaction and the kernels don't seem to stop since (I am assuming the kernel resources/state get all mixed up due to the way i have it coded). But both your comments about "...start another kernel on that process" and "POE::Wheel::Run ... Nested POE Kernels" seem to be interesting. i will explore that option. Any additional pointers to these topics? In the mean time if you have suggestion on how i can achieve the above i will aprreciate it. I know it is difficult to provide input based just on pure white-paper text as above instead of looking at code samples and ruuning example outputs. Regards Deven. p.s: For my problem of using perl's fork and POE in the same script I turned on some debugging on POE::Kernel and observed that there may be some interaction with handling the "CHLD" signal. All the sessions in POE::Kernel terminate succesfully and there are no resources in use, except the POE::Kernel seems to some how wait for the forked child (that happen outside of POE::Kernel) to finish. Once those forked child process are done (killed) the POE::Kernel seems to retrun. I am not sure how/why POE::Kernel gets a signal handler registered to keep waiting for process forked outside of it. I had forked those process before running the POE::Kernel. On Wed, Jan 14, 2009 at 11:40 AM, wrote: > > This got me to thinking > > Setup a POE::Wheel::Followtail for each file you want to tail. No need > to spawn off other processes. > > If you DO need separate processes, from the main process run a > POE::Wheel::Run and start another kernel on that process. Setup a > Followtail wheel for the input and handle the output back to the Main code > via STDOUT and the Run object. > > I tend to use fork sparingly and if you need to do alot of things > simultaneously, you should probably handle those in POE first. > > HTH, > > Dougie!!! > > -Original Message- > From: Robert Landrum > To: Deven Parekh > Cc: [email protected] > Sent: Tue, 13 Jan 2009 6:51 pm > Subject: Re: POE and perl fork interaction > > It's not clear what you're trying to do, but I suspect that you're doing it > wrong. :( > > Is there a reason why you don't use POE::Wheel::Run to tail the files? > > There's also: > > http://search.cpan.org/~rcaputo/POE-1.003/lib/POE/Wheel/FollowTail.pm > > I suspect that your forked tail process may have events queued from the > parent, as outlined in POE::Wheel::Run section on Nested POE Kernels. > > Good luck. > > Rob > > Deven Parekh wrote: > > Hello, > > > > Is it possible to use POE and the fork function in the same script. > > I am running into an interaction problem where the POE::Kernel does not > > return if i have forked off other process outside of the POE. Any input > on > > what I may be doing wrong > > > > Here is the psuedo code logic of my script > > > > #--- Call a function to fork off a process to start tailing some files > > #--- store its the above pids so we can terminate later > > > > #--- Call POE::Wheel::Run to do some task > > > > #--- After the above POE task returns kill the tailing process > > > > > > If i do not do the forking for tailing files, the P
Re: POE and perl fork interaction
Hello Rob, Dougie, Thanks for the suggestion. I apologize for not being clear on what i am trying to achieve. Basically I have built a wrapper module around POE to handle certain tasks. This allows the user of the wrapper module to be ignorant about POE. Each task has its own wrapper module and interface. examples of task is - tailig of files, has its own set of wrapper module - placing a test VOIP call to VOIP server under test, has its own set of wrapper module - verifying contents in tailed files, has it own set of wrapper module I want each of these to be independent POE wrappers and an independent way to start/stop each of the task. I have POE::Kernel->run per set of wrapper modules that starts of the task. I tried to create a set of wrapper module for the file tailing using POE::Component::IKC POE::Wheel::FollowTail (i wanted to tail files on remote machines, so also looked at POE::Componenet::RemoteTail) POE::Wheel::Run But since POE::Kernel is a singleton per process when i have a script that is trying to launch multiple task (implying multiple sets of wrappers) there is lot of interaction and the kernels don't seem to stop since (I am assuming the kernel resources/state get all mixed up due to the way i have it coded). But both your comments about "...start another kernel on that process" and "POE::Wheel::Run ... Nested POE Kernels" seem to be interesting. i will explore that option. Any additional pointers to these topics? In the mean time if you have suggestion on how i can achieve the above i will aprreciate it. I know it is difficult to provide input based just on pure white-paper text as above instead of looking at code samples and ruuning example outputs. Regards Deven. p.s: For my problem of using perl's fork and POE in the same script I turned on some debugging on POE::Kernel and observed that there may be some interaction with handling the "CHLD" signal. All the sessions in POE::Kernel terminate succesfully and there are no resources in use, except the POE::Kernel seems to some how wait for the forked child (that happen outside of POE::Kernel) to finish. Once those forked child process are done (killed) the POE::Kernel seems to retrun. I am not sure how/why POE::Kernel gets a signal handler registered to keep waiting for process forked outside of it. I had forked those process before running the POE::Kernel. On Wed, Jan 14, 2009 at 11:40 AM, wrote: > > This got me to thinking > > Setup a POE::Wheel::Followtail for each file you want to tail. No need > to spawn off other processes. > > If you DO need separate processes, from the main process run a > POE::Wheel::Run and start another kernel on that process. Setup a > Followtail wheel for the input and handle the output back to the Main code > via STDOUT and the Run object. > > I tend to use fork sparingly and if you need to do alot of things > simultaneously, you should probably handle those in POE first. > > HTH, > > Dougie!!! > > -Original Message- > From: Robert Landrum > To: Deven Parekh > Cc: [email protected] > Sent: Tue, 13 Jan 2009 6:51 pm > Subject: Re: POE and perl fork interaction > > It's not clear what you're trying to do, but I suspect that you're doing it > wrong. :( > > Is there a reason why you don't use POE::Wheel::Run to tail the files? > > There's also: > > http://search.cpan.org/~rcaputo/POE-1.003/lib/POE/Wheel/FollowTail.pm > > I suspect that your forked tail process may have events queued from the > parent, as outlined in POE::Wheel::Run section on Nested POE Kernels. > > Good luck. > > Rob > > Deven Parekh wrote: > > Hello, > > > > Is it possible to use POE and the fork function in the same script. > > I am running into an interaction problem where the POE::Kernel does not > > return if i have forked off other process outside of the POE. Any input > on > > what I may be doing wrong > > > > Here is the psuedo code logic of my script > > > > #--- Call a function to fork off a process to start tailing some files > > #--- store its the above pids so we can terminate later > > > > #--- Call POE::Wheel::Run to do some task > > > > #--- After the above POE task returns kill the tailing process > > > > > > If i do not do the forking for tailing files, the POE::Kernel returns > after > > the > > task is completed, but if I fork of the tailing process as above, > > the POE::Kernel never returns. > > > > Any input will be appreciated. > > > > Thanks in advance. > > > > BR > > DP > > p.s: I thought i had read about this interaction somewhere in > documentation > > but am not > > able toget to it to follow discussion around it, if any. > > > > > > -- > Which stars will make the biggest headlines in 2009? Get Hollywood > predictions, celebrity holiday photos and more with the PopEater > Toolbar<http://toolbar.aol.com/popeater/download.html?ncid=emlweusdown0025>. > >
Re: POE and perl fork interaction
This got me to thinking Setup a POE::Wheel::Followtail for each? file you want to tail.? No need to spawn off other processes. If you DO need separate processes, from the main process run a POE::Wheel::Run and start another kernel on that process.? Setup a Followtail wheel for the input and handle the output back to the Main code via STDOUT and the Run object. I tend to use fork sparingly and if you need to do alot of things simultaneously, you should probably handle those in POE first. HTH, Dougie!!! -Original Message- From: Robert Landrum To: Deven Parekh Cc: [email protected] Sent: Tue, 13 Jan 2009 6:51 pm Subject: Re: POE and perl fork interaction It's not clear what you're trying to do, but I suspect that you're doing it wrong. :(? ? Is there a reason why you don't use POE::Wheel::Run to tail the files?? ? There's also:? ? http://search.cpan.org/~rcaputo/POE-1.003/lib/POE/Wheel/FollowTail.pm? ? I suspect that your forked tail process may have events queued from the parent, as outlined in POE::Wheel::Run section on Nested POE Kernels.? ? Good luck.? ? Rob? ? Deven Parekh wrote:? > Hello,? >? > Is it possible to use POE and the fork function in the same script.? > I am running into an interaction problem where the POE::Kernel does not? > return if i have forked off other process outside of the POE. Any input on? > what I may be doing wrong? >? > Here is the psuedo code logic of my script? >? > #--- Call a function to fork off a process to start tailing some files? > #--- store its the above pids so we can terminate later? >? > #--- Call POE::Wheel::Run to do some task? >? > #--- After the above POE task returns kill the tailing process? >? >? > If i do not do the forking for tailing files, the POE::Kernel returns after? > the? > task is completed, but if I fork of the tailing process as above,? > the POE::Kernel never returns.? >? > Any input will be appreciated.? >? > Thanks in advance.? >? > BR? > DP? > p.s: I thought i had read about this interaction somewhere in documentation? > but am not? > able toget to it to follow discussion around it, if any.? >? > ?
Re: POE and perl fork interaction
It's not clear what you're trying to do, but I suspect that you're doing it wrong. :( Is there a reason why you don't use POE::Wheel::Run to tail the files? There's also: http://search.cpan.org/~rcaputo/POE-1.003/lib/POE/Wheel/FollowTail.pm I suspect that your forked tail process may have events queued from the parent, as outlined in POE::Wheel::Run section on Nested POE Kernels. Good luck. Rob Deven Parekh wrote: Hello, Is it possible to use POE and the fork function in the same script. I am running into an interaction problem where the POE::Kernel does not return if i have forked off other process outside of the POE. Any input on what I may be doing wrong Here is the psuedo code logic of my script #--- Call a function to fork off a process to start tailing some files #--- store its the above pids so we can terminate later #--- Call POE::Wheel::Run to do some task #--- After the above POE task returns kill the tailing process If i do not do the forking for tailing files, the POE::Kernel returns after the task is completed, but if I fork of the tailing process as above, the POE::Kernel never returns. Any input will be appreciated. Thanks in advance. BR DP p.s: I thought i had read about this interaction somewhere in documentation but am not able toget to it to follow discussion around it, if any.
