[Zope-dev] xron does not work with python 2.2
Hi there, it seams that the Product XRON does not work with python 2.2. I can create an instance, however when I try to enter into it from the zmi, I get an error: The object at http://localhost:8080/sprint/scheduler has an empty or missing docstring. Objects must have a docstring to be published. When I run the same site with Python 2.13 everything is fine. What could be the reason for that? thanks Robert -- mit freundlichen Grüssen Robert Rottermann www.redCOR.ch ___ Zope-Dev maillist - [EMAIL PROTECTED] http://mail.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://mail.zope.org/mailman/listinfo/zope-announce http://mail.zope.org/mailman/listinfo/zope )
Re: [Zope-dev] xron does not work with python 2.2
it seams that the Product XRON does not work with python 2.2. Perhaps you should be thankful .. We tried to use xron a year or so ago, and it bit us repeatedly. We dropped it and use cron to tickle a Zope URL or to call an external method. For those, see: http://mail.zope.org/pipermail/zope/2003-February/131882.html http://article.gmane.org/gmane.comp.web.zope.plone.user/2490 -- Jean Jordaan http://www.upfrontsystems.co.za ___ Zope-Dev maillist - [EMAIL PROTECTED] http://mail.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://mail.zope.org/mailman/listinfo/zope-announce http://mail.zope.org/mailman/listinfo/zope )
Re: [Zope-dev] xron does not work with python 2.2
robert wrote at 2003-9-23 12:57 +0200: it seams that the Product XRON does not work with python 2.2. I can create an instance, however when I try to enter into it from the zmi, I get an error: The object at http://localhost:8080/sprint/scheduler has an empty or missing docstring. Objects must have a docstring to be published. When I run the same site with Python 2.13 everything is fine. What could be the reason for that? A new type check has been added to ZPublisher.BaseRequest to prevent ZPublisher to publish elementary Python types in Python 2.2. Maybe, you get hit by this. If not, check that the object has indeed a docstring. Dieter ___ Zope-Dev maillist - [EMAIL PROTECTED] http://mail.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://mail.zope.org/mailman/listinfo/zope-announce http://mail.zope.org/mailman/listinfo/zope )
[Zope-dev] Xron on linux: Dispatcher thread stops after a while
ZOPE 2.2.2 , Xron -0-0-9, Python 1.5.2 Hi Steve, I am running Zope under linux (Suse 6.4). And I would like to use Xron. But, I can not get it running. I did read your email : Xron on linux. And therefore I would like to know, how you did manage to use Xron. I have the general Xron problem, that the zope-server is not responding anymore after the installation of Xron. Thanks, Els Homan ___ Zope-Dev maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope )
Re: [Zope-dev] Xron on linux: Dispatcher thread stops after a while
Homan Els wrote: ZOPE 2.2.2 , Xron -0-0-9, Python 1.5.2 Hi Steve, I am running Zope under linux (Suse 6.4). And I would like to use Xron. But, I can not get it running. I did read your email : Xron on linux. And therefore I would like to know, how you did manage to use Xron. I have the general Xron problem, that the zope-server is not responding anymore after the installation of Xron. What user do you run Zope as? There's a problem with Linux where if you start off a thread, then change uid in the main thread, the thread that you spawned before will remain in the old uid, or unexpected things will happen. This is what Zope does when you run it as root. Zope initializes its products as root, and then changes to user nobody. You can find out more about this if you search for discussions about BIND and Linux. The solution for Zope and Xron is to run Zope as user nobody. You might need to chown the files in your zope directory. Note that you will not be able to run Zope on a privileged port (below 1024) if you do this. The alternative is to hack Zope so that it calls Xron after it has changed use to nobody, so Xron can safely spawn its thread as user nobody. If you do this, you'll be able to run zope as the root user, and Zope + Xron will work running on port 80. -- Steve Alexander Software Engineer Cat-Box limited ___ Zope-Dev maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope )
[Zope-dev] Xron running under linux
Hi Nick, The point is that linux has a different thread system then other platforms. Under standard UNIX (hpux, sgi, etc.), you have the possibility to create a thread. When creating one or more threads, you will have: 1 process with one or more threads sharing the same environment (such as uid, etc.). In this case, when changing a env. var. this will be available in both threads. But, when creating a thread in linux you will have: for each thread one process (you can see this with ps -ef|grep python). In this case, when changing a env.var. this will give a problem, because the other thread still have the old uid. Zope is starting as root. Zope initializes its products (create a thread) as root, and then changes to user "nobody" (or to user >given by -u (in the startup). So, the thread does have another uid, and this is giving the problem! I just change my: rczope: su wwwrun -c "$zope_start 2>/dev/null" because in my start script, I call: exec /usr/local/zope/bin/python $PYTHONHOME/z2.py -u wwwrun -a 127.0.0.1 "$@" You might need to chown the files in your zope directory. I did try to run the Xron product and everything is working correctly now. Enjoy it !. Els Nicholas Lo wrote: Hi Els, Sorry for I couldnt give you the code in time. BTW, what are your tricks in making Xron working under Linux??? If Xron works under Linux, I can throw away my old code and follow the Xron way. -- Nick - Original Message - From: "Homan Els" [EMAIL PROTECTED]> To: "Nicholas Lo" [EMAIL PROTECTED]> Sent: Monday, May 28, 2001 6:47 PM Subject: [Fwd: [Zope-dev] Xron on linux: Dispatcher thread stops after a while] > Hi Nicholas, > > It is working ! > (I will now try to test to correctness of the product). > > See email from Xron on linux. > > Regards, > > Els > > >
[Zope-dev] Xron error!!!
My Xron file has gone crazy and does not stop running. I have stopped my server and started it again, but the xron file is still running. This causes the Z2.log file and Data.fs files to grow to enormous files and I struggle to be able to log into the system. First: Can I delete the overloaded Data.fs file in the var/ directory, or will this cause serious trouble? Secondly: Is there a cure against that void Xron file of mine or must I manually delete it from were my own files are stored? Thanks for any kind of help, Espen ___ Zope-Dev maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope )
RE: [Zope-dev] Xron error!!!
1. If you can use the management interface, you can disable a Xron Scheduled Method by deleting it from the Schedule catalog or setting its reschedule interval to null. 2. If you delete (or just rename __init__.py to something else in) the Xron Product. And restart Zope, there will be no Dispatcher to execute Xron Scheduled Methods; so looping will stop. 3. The messages in the log file should indicate what kind of error the Xron Dispatcher is encountering. If this is some kind of environmental condition, perhaps you can fix it external to Zope and the Dispatcher will stop looping. 4. The Dispatcher is designed to cancel erring Xron Scheduled Method, precisely so that it will not go into a loop. The fact that it seems to be looping indicated some very unusual condition. Please let us know what the log file says. 5. You can truncate the bloated tail end of a Data.fs file using standard system tools. I don't remember how right at the moment, but a search in the mail archives on trucate and data.fs might be fruitful. Don't throw away the original file, because you might truncate other transactions that you wanted to save. IOW, finding the right spot to truncate is the trick. -- HTH -- Loren -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Espen Sorbye Frederiksen Sent: Thursday, May 24, 2001 13:06 To: [EMAIL PROTECTED] Subject: [Zope-dev] Xron error!!! My Xron file has gone crazy and does not stop running. I have stopped my server and started it again, but the xron file is still running. This causes the Z2.log file and Data.fs files to grow to enormous files and I struggle to be able to log into the system. First: Can I delete the overloaded Data.fs file in the var/ directory, or will this cause serious trouble? Secondly: Is there a cure against that void Xron file of mine or must I manually delete it from were my own files are stored? Thanks for any kind of help, Espen ___ Zope-Dev maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope ) ___ Zope-Dev maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope )
RE: [Zope-dev] Xron error!!!
On Thu, 24 May 2001, Loren Stafford wrote: 5. You can truncate the bloated tail end of a Data.fs file using standard system tools. I don't remember how right at the moment, but a search in the mail archives on trucate and data.fs might be fruitful. Use the unix command 'split'. I immagine cygwin ports this simple program to windows. Of course, you can also do the truncation in a couple lines of python, but I'll leave that as an exercise to the reader. ;) -Michel ___ Zope-Dev maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope )
Re: [zope-dev] Xron, suse 6.4
Hi, Could you please send your external python method. + Product for using in combination with a cron job. Because, this can really help me a lot. Thanks, Els Nicholas Lo wrote: Sorry man, I still have the same problem :( However, instead I use Xron, I write a simple product which is able to call up another python process to the cron job. Though this is not a perfect solution, it solve many of my problems. My simple 'external' python program does not sit inside the Zope framework, so it cannot benefit from Zope's many good features :( -- nick - Original Message - From: Homan Els [EMAIL PROTECTED] To: Nicholas Lo [EMAIL PROTECTED] Cc: [EMAIL PROTECTED]; [EMAIL PROTECTED] Sent: Wednesday, May 16, 2001 10:55 PM Subject: [zope-dev] Xron, suse 6.4 Hi Nick, I am having the same problem with installing Xron on my suse 6.4 machine. My question is, are you now running Xron with succes ? And how did you do this ...? Because, I would like to run this product as well. Thanks, Els * - Original Message - From: Nicholas Lo [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: August 18, 2000 12:41 AM Subject: xcron test Hi Loren, I have a problem with installing Xron 0.9 onto my machine. Currently, I'm running SuSE Linux 6.4 on a 600MHz/128Mb/20Gb PC. I have followed the release note and set the STUPID_LOG_FILE environment variable to point the log file, and Xron itself is, of course, resides in the /Products directory. When I start Zope, the console looks okay. However, the browser keeps on loading and loading and could not show the Zope management screen. I have also tried Xron on my notebook, which is running Win98. Everything works just fine. I just wonder what's gone wrong. Thanks. Nick ** -- ___ Els Homan European Molecular Biology Laboratory (EMBL) 6, rue Jules Horowitz, B.P.181 38042 Grenoble cedex 9. France [EMAIL PROTECTED] (Email) 04 76 20 74 66 (Phone) 04 76 20 71 99 (Fax) __ -- ___ Zope-Dev maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope )
[zope-dev] Xron, suse 6.4
Hi Nick, I am having the same problem with installing Xron on my suse 6.4 machine. My question is, are you now running Xron with succes ? And how did you do this ...? Because, I would like to run this product as well. Thanks, Els * - Original Message - From: Nicholas Lo [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: August 18, 2000 12:41 AM Subject: xcron test Hi Loren, I have a problem with installing Xron 0.9 onto my machine. Currently, I'm running SuSE Linux 6.4 on a 600MHz/128Mb/20Gb PC. I have followed the release note and set the STUPID_LOG_FILE environment variable to point the log file, and Xron itself is, of course, resides in the /Products directory. When I start Zope, the console looks okay. However, the browser keeps on loading and loading and could not show the Zope management screen. I have also tried Xron on my notebook, which is running Win98. Everything works just fine. I just wonder what's gone wrong. Thanks. Nick ** -- ___ Els Homan European Molecular Biology Laboratory (EMBL) 6, rue Jules Horowitz, B.P.181 38042 Grenoble cedex 9. France [EMAIL PROTECTED] (Email) 04 76 20 74 66 (Phone) 04 76 20 71 99 (Fax) __ ___ Zope-Dev maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope )
[Zope-dev] Xron
Hi, I did install the xron product from Istaffor, but it doesn't work. I am using Zope - .2.3.2, and installed xron. But, when I want to access the zope - server, I get a zero response back. Does anyone no the answer to this problem ? Thanks, Els Homan __ ___ Zope-Dev maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope )
RE: [Zope-dev] Xron
This is a known problem. Search back thru the archives of [EMAIL PROTECTED] for Xron and you will find some helpful information. I'll also try to find the relevant email and forward it to you separately. -- Loren (lstaffor) -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Homan Els Sent: Friday, May 11, 2001 06:23 To: [EMAIL PROTECTED] Subject: [Zope-dev] Xron Hi, I did install the xron product from Istaffor, but it doesn't work. I am using Zope - .2.3.2, and installed xron. But, when I want to access the zope - server, I get a zero response back. Does anyone no the answer to this problem ? Thanks, Els Homan __ ___ Zope-Dev maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope ) ___ Zope-Dev maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope )
Re: [Zope-dev] Xron fragility
Yes, using Client.py was the easiest way to do that. The biggest problem with Client.py is its dependency on HTTP. If your server is set up to only accept HTTPS, then you can't use Xron -- not a desirable trade-off. If security is the problem, you could configure the HTTP part to listen only on a loopback interface. (yes, this is supported on NT and windows 95 too) We need another mechanism that achieves the same goal -- simulating the environment of a request -- without going all the way back to the socket. I always thought the use of Client was very elegent. The performance hit is negligible, and all the plausible alternatives need many more lines of code. Another advantage is that it promotes testability of the scheduled events since it is easy (trivial) to reproduce the environment in which they run when scheduled. Toby Dickenson [EMAIL PROTECTED] ___ Zope-Dev maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope )
Re: [Zope-dev] Xron fragility
From: "Kapil Thangavelu" [EMAIL PROTECTED] [snip] Xron has a single dispatcher thread. This thread knows how long to sleep for until the next job needs to run. this model has problems when new jobs (for immeadiate execution) are entered after the system sleeps. i think it should it taken into account that people will use this dispatching thread to achieve async operations on a request, and that these might need to be done immeadiately. This is not (or should not be) a problem in current Xron design. The Dispatcher wakes up early if the Schedule catalog is changed. -- Loren ___ Zope-Dev maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope )
Re: [Zope-dev] Xron fragility
What if you want a small job to be done every 30 seconds? I generally don't... I'm satisfied with cron granularity, although others might not be. Do you have this requirement? I thought a little about the granularity issue and decided to go with the most general solution. I have no requirement for 30-second intervals, but I wanted to avoid support requests from those who might have such a need. Also, I have no need for large numbers of scheduled methods. But I used a heavy-duty data structure (Catalog) and the sleeping dispatcher model, just so there would be no arbitrary limits that would cause me support headaches later. It uses Client.py to run a job. Why is this? This doesn't make any sense to me on its face. Why not just call the method from a separate thread? Which separate thread? Do you create a new ZODB thread? That sounds as if it might use quite a few resources. Is there a Zope API for making ZODB threads call methods on objects, as signalled by other threads? I'm guessing the easiest way to do that is to use Client.py to make a new http request. Yes, using Client.py was the easiest way to do that. The biggest problem with Client.py is its dependency on HTTP. If your server is set up to only accept HTTPS, then you can't use Xron -- not a desirable trade-off. We need another mechanism that achieves the same goal -- simulating the environment of a request -- without going all the way back to the socket. -- Loren ___ Zope-Dev maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope )
[Zope-dev] Xron fragility
The Xron product seems rather "fragile" in use. That is, if things go wrong when an Xron DTML Method is triggered, that method doesn't get rescheduled. An example of this is that my intranet DNS server needed to be rebooted. Xron couldn't look up the appropriate domain name, and stopped working. -- 2000-10-11T08:16:34 PROBLEM(100) Products.Xron.Loggerr Trigger event: http://my.development.server:4080/my_xron_method Trigger time: 2000/10/11 09:14:00 GMT+1 Failed to trigger event. Type=bci.NotAvailable Val=host not found (File: http://my.development.server/my_xron_method/trigger Line: []) None None for None -- 2000-10-11T08:19:04 PROBLEM(100) Products.Xron.Loggerr Failed to disarm event Also, if something bad happens in the Dispatcher thread, the thread dies. Before I leap in and start patching Xron, I'd like to have a discussion about how Xron should handle problems. My first thought is that on errors in the dispatcher thread, Xron should enter an "error state" where it probes every so often to see whether it can resume normal operation. The length of time between probes could increase with each probe, to give good performance with transient problems whilst preventing Xron from choking resources. -- Steve Alexander Software Enigneer Cat-Box limited http://www.cat-box.net ___ Zope-Dev maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope )
Re: [Zope-dev] Xron fragility
Steve, I am also interested in scheduling... though I haven't looked closely at Xron. The Xron product seems rather "fragile" in use. That is, if things go wrong when an Xron DTML Method is triggered, that method doesn't get rescheduled. Does Xron take an optimistic approach to repeating jobs? In other words, does it assume every job is a one-time job and that the last duty that a repeating job performs is to reschedule itself? An example of this is that my intranet DNS server needed to be rebooted. Xron couldn't look up the appropriate domain name, and stopped working. -- 2000-10-11T08:16:34 PROBLEM(100) Products.Xron.Loggerr Trigger event: http://my.development.server:4080/my_xron_method Trigger time: 2000/10/11 09:14:00 GMT+1 Failed to trigger event. Type=bci.NotAvailable Val=host not found (File: http://my.development.server/my_xron_method/trigger Line: []) None None for None -- 2000-10-11T08:19:04 PROBLEM(100) Products.Xron.Loggerr Failed to disarm event Also, if something bad happens in the Dispatcher thread, the thread dies. What does the Dispatcher thread do? Does it fire off worker threads? Before I leap in and start patching Xron, I'd like to have a discussion about how Xron should handle problems. My first thought is that on errors in the dispatcher thread, Xron should enter an "error state" where it probes every so often to see whether it can resume normal operation. The length of time between probes could increase with each probe, to give good performance with transient problems whilst preventing Xron from choking resources. What are other threads in Xron doing while the Dispatcher thread is hosed? What are the other threads? ___ Zope-Dev maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope )
Re: [Zope-dev] Xron fragility
Chris McDonough wrote: Steve, I am also interested in scheduling... though I haven't looked closely at Xron. The Xron product seems rather "fragile" in use. That is, if things go wrong when an Xron DTML Method is triggered, that method doesn't get rescheduled. Does Xron take an optimistic approach to repeating jobs? In other words, does it assume every job is a one-time job and that the last duty that a repeating job performs is to reschedule itself? It is the Xron DTML Method's responsibility to reschedule itself. It could be its first duty, however. Then again, as all the work happens inside a ZODB transaction, it doesn't matter when the reschedule happens. What does the Dispatcher thread do? Does it fire off worker threads? Xron has a single dispatcher thread. This thread knows how long to sleep for until the next job needs to run. It uses Client.py to run a job. Jobs are Xron DTML Methods. They have a "trigger" method that gets called through the web from localhost, by the Dispatcher thread. Before I leap in and start patching Xron, I'd like to have a discussion about how Xron should handle problems. My first thought is that on errors in the dispatcher thread, Xron should enter an "error state" where it probes every so often to see whether it can resume normal operation. The length of time between probes could increase with each probe, to give good performance with transient problems whilst preventing Xron from choking resources. What are other threads in Xron doing while the Dispatcher thread is hosed? What are the other threads? There are no other threads in Xron. Xron creates a single thread to do all event dispatching. The work is done in Zope ZODB threads (or whatever the correct terminology is). The dispatcher thread communicates with a ZODB thread by using Client to make a web request. Xron usually makes requests as the anonymous user. However, I've patched my Xron to make requests as XronUser by hardcoding (!) the username and password for that in the RPC.py module of Xron. Then, I've manually created a XronUser user in my root user folder. I give XronUser the local roles needed to run methods I want to be scheduled via Xron. This is not the ideal way to make Xron use authentication. I posted a proposed design for that to zope-dev in August. http://lists.zope.org/pipermail/zope-dev/2000-August/006548.html http://lists.zope.org/pipermail/zope-dev/2000-August/006549.html http://lists.zope.org/pipermail/zope-dev/2000-August/006550.html -- Steve Alexander Software Engineer Cat-Box limited http://www.cat-box.net ___ Zope-Dev maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope )
Re: [Zope-dev] Xron fragility
Chris McDonough wrote: As a side note, I do not like the fact that Xron requires you to use special DTML methods. I suppose this is a requirement in this architecture due to the fact they need to be autocataloged, but I don't really like that feature either :-). I think Xron could work with anything that has "trigger" and "disarm" methods, that gets put into the Schedule catalog. What does the Dispatcher thread do? Does it fire off worker threads? Xron has a single dispatcher thread. This thread knows how long to sleep for until the next job needs to run. Do you think this is this any more effective than having a producer thread do a lookup every minute to see what jobs are current, after which it should put the current jobs in a queue? What if you want a small job to be done every 30 seconds? It uses Client.py to run a job. Why is this? This doesn't make any sense to me on its face. Why not just call the method from a separate thread? Which separate thread? Do you create a new ZODB thread? That sounds as if it might use quite a few resources. Is there a Zope API for making ZODB threads call methods on objects, as signalled by other threads? I'm guessing the easiest way to do that is to use Client.py to make a new http request. I see... would it be naive if I were to say that I think that a scheduler should fire off threads of its own and not rely on an external facility to run the jobs? I'd really like to see a scheduler as a standard part of Zope. I think it would be good to have scheduled methods called from within Zope, rather then going through http. I don't know enough about how ZPublisher/ZODB works to know where to start this though. -- Steve Alexander Software Engineer Cat-Box limited http://www.cat-box.net ___ Zope-Dev maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope )
Re: [Zope-dev] Xron fragility
As a side note, I do not like the fact that Xron requires you to use special DTML methods. I suppose this is a requirement in this architecture due to the fact they need to be autocataloged, but I don't really like that feature either :-). I think Xron could work with anything that has "trigger" and "disarm" methods, that gets put into the Schedule catalog. I guess I'm not real real hot on the dependency on a catalog at all. I'm having a hard time imagining a situation where you have so many events that you need to index them -- especially using a ZCatalog. It just seems like too many moving parts and overkill for the job. :-) Xron has a single dispatcher thread. This thread knows how long to sleep for until the next job needs to run. Do you think this is this any more effective than having a producer thread do a lookup every minute to see what jobs are current, after which it should put the current jobs in a queue? What if you want a small job to be done every 30 seconds? I generally don't... I'm satisfied with cron granularity, although others might not be. Do you have this requirement? It uses Client.py to run a job. Why is this? This doesn't make any sense to me on its face. Why not just call the method from a separate thread? Which separate thread? Do you create a new ZODB thread? That sounds as if it might use quite a few resources. Is there a Zope API for making ZODB threads call methods on objects, as signalled by other threads? I'm guessing the easiest way to do that is to use Client.py to make a new http request. Well... AFAIK, there is no such thing as a ZODB thread... there are a number of Python threads used by Zope. We'd just fire off another one to perform a task as part of the thing that takes an event off the queue. This might be naive. I need to try it. I'd really like to see a scheduler as a standard part of Zope. I think it would be good to have scheduled methods called from within Zope, rather then going through http. I don't know enough about how ZPublisher/ZODB works to know where to start this though. I'll need to try to call get_transaction().commit() from a manually-constructed Python thread fired off from Zope and see what happens. I think it'll just work. I'll find out in a few minutes. :-) ___ Zope-Dev maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope )
Re: [Zope-dev] Xron fragility
I'll need to try to call get_transaction().commit() from a manually-constructed Python thread fired off from Zope and see what happens. I think it'll just work. I'll find out in a few minutes. :-) Yes, it just works. :-) ___ Zope-Dev maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope )
Re: [Zope-dev] Xron fragility
Do you think this is this any more effective than having a producer thread do a lookup every minute to see what jobs are current, after which it should put the current jobs in a queue? E.g., as the "run" method of a separate producer thread: the same problem applies, a solution might be a timer and a signal handler to catch a signal event when a new job is entered into the system. events could be managed as some sort of collection of linked lists (or whatever ds). I think this problem is solved by: - polling for "current" events every 60 seconds *exactly on the 0th second of the minute* (this ensures that stopping and starting the scheduler won't accidently cause a "current" repeating event to fire twice). - allowing one-time events (which are most likely to need to be executed immediately) to be "current" for the minute implied by the event's timestamp as well as the minute just before that one. This ensures that an event that has a timestamp that was "current" when entered, but has subsequently been passed due to event polling overhead will be executed (even if it is entered at hh:mm:59.999 or similar). It also assumes that the scheduling poller will never take more than 60 seconds to poll all events, which is a fairly safe assumption. - the executor of the event is required to invalidate one-time events once they've been executed (or before they're executed) so they don't get fired twice. I don't believe there is any need for a signal handler or anything of the sort, the problem seems to just require careful synchronization. i played around with this in a monitor thread and you just can't achieve the proper semantics to execute an arbitray zope method. you have to recreate the request, response as well as have all the required support modules (DTML, tracebacks, etc) to successfully call a method, you are in essence reduplicating the publishing machinery. i tried to think of a way to get around this but i came up short. you can still access variables and simple methods. This would need to be thought through... the same problem exists for unit testing. :-( I see... would it be naive if I were to say that I think that a scheduler should fire off threads of its own and not rely on an external facility to run the jobs? the dispatcher thread itself has a connection to the ZODB, its using client as RPC to invoke the methods on Publishing threads. Since there is a hardcoded limit to ZODB connections firing off more connections does not seem like a good idea. AFAIK, threads will block if they can't get a DB connection. What risks does that imply? Is it a problem? ___ Zope-Dev maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope )
Re: [Zope-dev] Xron and security
Loren Stafford wrote: Thanks, Steve. I have few questions below 8-) (I'm always better with questions than answers.) -- Loren From: "Steve Alexander" [EMAIL PROTECTED] Hi Loren, I'd be glad to listen to well considered proposals for how Xron should handle security. Consider this a "straw man". On installation, Xron creates a user in the root user folder called "XronUser". Xron is resonsible for setting this user's password. Therefore, it is known to both the Xron product, and also to the root user folder. When a Xron method is run, there is a property that indicates whether it is called anonymously, or authenticated as XronUser. Is there a good reason not to always pass authentication in the request? The authentication property would have to be stored in the Schedule catalog, and I'd like to keep the Schedule as small as possible. I can't think of a concrete example of when I'd want to have a Xron method called with no authentication, when authentication is available. XronUser would be a privilaged user, and it might be useful to run scheduled methods without using that privilage. However, in the 2.2 security model, you can drop privilage using proxy roles, so I don't think your suggestion above is a limitation. So, no, I can't see a good reason not to always pass authentication in the request. The Xron product could change the password of XronUser every day to a new random value. That's more than folks do to maintain secrecy of the "superuser" password. Is the extra trouble worthwhile? I put this in as an example to illustrate that only the Xron product, and the Zope root user folder need to know the XronUser password. You're right, it really doesn't need to change every day :-) However, there should be manage_... method in Xron that will change the password to a new random value. Then, if people wanted the password changed every day, they could use a Xron DTML Method to do it :-) Perhaps also a button somewhere in the Xron product, or in the Schedule, to call the manage_resetXronPassword method. The domains associated with XronUser could be just localhost.localdomain (not sure about this). Or based on whatever the machine's host-name is (probably better). At a virtual-hosted site, how could Xron know what the host-name is? Xron must know (in some sense) what the host name is now, in order to use ZClient to call a Xron DTML Method. I guess this is because the URL to use comes from absolute_url() in Zope. I'm using Xron 0.0.9 on a virtual-hosted site, and it works. However, restricting a User's domains doesn't work as I would expect. The configuration is ZServer behind Apache+ProxyPass. If I put any value in the "domains" field of a User, other than "127.0.0.1", that User cannot log in at all. I haven't looked into this particularly yet. In AccessControl/User.py, login restriction by domain works using REMOTE_HOST and REMOTE_ADDR from the REQUEST. I sent myself an email from a Xron DTML Method on two Zope 2.2.1b1 machines, one just running ZServer, the other virtual-hosted as described above. In the case of the virtual-hosted server, I get emailed REMOTE_ADDR 127.0.0.1 In the case of the bare ZServer, I get emailed REMOTE_ADDR my_server's_ip_address Also, for the virtual server, ZClient seems to choose an appropriate HTTP_HOST. So, it seems that the correct domain restriction to use depends on just how you're using ZServer. I can think of three ways around this: 1: Don't bother restricting by domain for XronUser. 2: Allow a Manager to configure what domains XronUser may log in from. 3: Use ZClient to call a method in Xron. Xron inspects the REQUEST passed for this method, extracts the REMOTE_ADDR and REMOTE_HOST, and uses one of these as the domain restriction. If you go with 3, there will need to be some button in Xron's management interface to re-determine the correct domain to use. If I were writing the software, I'd choose 2, and let the Manager of a site make the decision. -- Steve Alexander Software Engineer Cat-Box ltd http://www.cat-box.net ___ Zope-Dev maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope )
[Zope-dev] Xron and security
Hi Loren, I'd be glad to listen to well considered proposals for how Xron should handle security. Consider this a "straw man". On installation, Xron creates a user in the root user folder called "XronUser". Xron is resonsible for setting this user's password. Therefore, it is known to both the Xron product, and also to the root user folder. When a Xron method is run, there is a property that indicates whether it is called anonymously, or authenticated as XronUser. The Xron product could change the password of XronUser every day to a new random value. The domains associated with XronUser could be just localhost.localdomain (not sure about this). Or based on whatever the machine's host-name is (probably better). Site administrators can assign local roles to XronUser as necessary. If Phillip Eby's proposed changes to the access file get included in some future version of Zope, XronUser could be included as one of these bootstrap users by simply writing to a file. -- Steve Alexander Software Engineer Cat-Box ltd http://www.cat-box.net ___ Zope-Dev maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope )
Re: [Zope-dev] Xron and security
Thanks, Steve. I have few questions below 8-) (I'm always better with questions than answers.) -- Loren From: "Steve Alexander" [EMAIL PROTECTED] Hi Loren, I'd be glad to listen to well considered proposals for how Xron should handle security. Consider this a "straw man". On installation, Xron creates a user in the root user folder called "XronUser". Xron is resonsible for setting this user's password. Therefore, it is known to both the Xron product, and also to the root user folder. When a Xron method is run, there is a property that indicates whether it is called anonymously, or authenticated as XronUser. Is there a good reason not to always pass authentication in the request? The authentication property would have to be stored in the Schedule catalog, and I'd like to keep the Schedule as small as possible. The Xron product could change the password of XronUser every day to a new random value. That's more than folks do to maintain secrecy of the "superuser" password. Is the extra trouble worthwhile? The domains associated with XronUser could be just localhost.localdomain (not sure about this). Or based on whatever the machine's host-name is (probably better). At a virtual-hosted site, how could Xron know what the host-name is? Site administrators can assign local roles to XronUser as necessary. If Phillip Eby's proposed changes to the access file get included in some future version of Zope, XronUser could be included as one of these bootstrap users by simply writing to a file. -- Steve Alexander Software Engineer Cat-Box ltd http://www.cat-box.net ___ Zope-Dev maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope )
