April 2000 - Zope - Zope lists

Re: [Zope] n-tier architecture
by Tony Rossignol 12 Apr '00

12 Apr '00

Greg Lappen wrote: > > Hi all, I am evaluating Zope as an alternative to J2EE (Enterprise Java > Beans, Java Server Pages, Servlets, etc.) In a J2EE application, the > JSP and servlet are the presentation layer, the EJB's are the business > logic layer, and the database is the data layer. How does this map to > Zope? The database remains the data layer. Business logic can be designed into Products and ZClasses. And the presentation layer is DTML. From a presentation layer centric environment this means your Designers - presentation layer workers - can produce much more efficiently than in JSP or Servlets the syntax much easier to use. Your Developers - business logic workers - can control access, deligate responsibility and code to one common interface. And you database people can continue to develope in the same space as before. > It looks like you put your business logic in DTML methods, but this > seems like the business logic would get scattered throughout the > presentation layer. If you try to put business logic in DTML it will get scattered all over the place. Look to ZClasses for simple business objects and a full blown Zope Product for complex objects. The product will mean work in Python, but from my experience it's a faily easy language to use. Good luck in your evaluation and keep us posted. -- ------------------------------- tonyr(a)ep.newtimes.com Director of Web Technology New Times, Inc. -------------------------------

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RE: [Zope] Re: Zope hanging (poss. threads-related)
by Marcus Collins 12 Apr '00

12 Apr '00

> -----Original Message----- > From: Michel Pelletier [mailto:michel@digicool.com] > Sent: 12 April 2000 02:29 > To: Marcus Collins > Cc: 'zope(a)zope.org' > Subject: Re: [Zope] Re: Zope hanging (poss. threads-related) <snip> > I suspect this problem *might* be unrelated to the threadlock > discussed so far, in the case of the reported lock, 2 or more > threads cause instability. In your case, you report 4 is stable. Our live server, running Zope 2.1.3 with 4 threads, has just had a thread hang. There has been no management activity on this server since last it was restarted about four hours ago. At the time of the hanging, a frameset was being requested (cf. my original post). A moment ago, I thought this might have something to do with the way ZServer handles pipelined requests, but the problem exists with PCGI as well as HTTP... I haven't yet come close to grokking ZServer, but my suspicions arose because I'd seen this hanging occur only on frameset pages, for which the client would quite reasonably send multiple requests on the same channel before receiving a response to the first. As our images are served directly by apache, framesets would be the only initiators of pipelined requests. So it's not protocol-specific, but this must be some kind of deadlock problem, or a thread stomping over another request, but beyond the level of the protocol being used. I'll be focussing on ZServer/medusa/* now... As mentioned, I've been testing Zope 2.1.6 under similar conditions, but with 20 threads. So far, I haven't been able to cause it to hang on the frameset pages. However, I have caused a single thread to hang by repeatedly refreshing a page (the method concerned happens to call an external method, if that adds relevant info.) I've hacked z2.py on both the 2.1.3 and 2.1.6 installations so that they instantiate a DebugLogger, and in both I've managed to catch several requests that did not end using Amos Latteier's analyser script. In all cases, the requests got only as far as the received input (I) stage. This brings up another point, which I came across in the Collector as well (http://classic.zope.org:8080/Collector/871/view) -- how does ZServer handle zombie requests? I noticed in HTTPServer.py that there is a "zombie_timeout" of 100 minutes (btw, there's also a zombie_timeout of 30 minutes in medusa/http_server.py) -- is the thread held up with the zombie request for the duration of this timeout and, if so, is it not conceivable that a number of zombies could deplete the threadpool to the extent that no further threads are available? I guess it depends on exactly what "hung" means in this case... Also, is it possible to track thread usage somewhere? I realise that all of this doesn't amount to much to go on... However, the problems are reproducible on my machine, and exacerbated as the NUMBER_OF_THREADS increases, so if anyone can guide me in where to look, I'll hopefully be able to apply that in testing this machine, and together we can get to the bottom of this (the wonder of OSS!). Regards, -- Marcus

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DateTime and ISO-dates
by Lennart Staflin 12 Apr '00

12 Apr '00

Hi all, I have some problems with DateTime in Zope. I generally want dates in the form 'YYYY-MM-DD'. But I can't figure out an easy way to get this with DateTime objects. There is a ISO method that produces both date and time: 'YYYY-MM-DD HH:MM:SS'. But nothing to get only the date. Perhaps one could wish for some addtions to the DateTime class. Some possibilities are, in order of preference: 1. Configurable default data format. 2. An ISODate method. 3. strftime method that uses localtime and not gmtime. Any other suggestions how to do this? -- Lennart Staflin <lennarts(a)infotek.no> /*/ STEP Infotek AS, http://www.infotek.no/ Gjerdrums vei 12, N-0486 Oslo, Norway

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Unidata 5.0 users
by DanZ 12 Apr '00

12 Apr '00

Help I need to be able to connect to a Unidata 5.0 server. Unidata Server (pre 5.0) basically used the Sybase Client libraries to connect to the data server. However, Ardent in all there wisdom, apparently changed the way you communicate with the server. I want to know if anyone else is using Zope to connect to Unidata, if so how. Or is anyone interested in writing a Unidata ZopeDA. Thanks Dan Zweifel I.S. Coordinator (Owensville Facility) danz(a)vonhoffmann.com ---------------------- Do you do Linux? :) Get your FREE @linuxstart.com email address at: http://www.linuxstart.com

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Ask Slashdot: Content management systems for Linux?
by Michael Bernstein 12 Apr '00

12 Apr '00

This story was posted today to the Q&A section of Slashdot: http://slashdot.org/article.pl?sid=00/04/11/1256247&mode=nested There are a few Zope related postings already, but I'm sure you can come up with a few points that haven't been made. ;-) Cheers, Michael Bernstein.

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Re: Zope hanging (poss. threads-related)
by Marcus Collins 12 Apr '00

12 Apr '00

Hi, First of all, thanks to all the folk who have contributed valuable information to this thread! I did originally increase the pool_size to 20 connections (I'm using ZMySQLDA 1.1.3, patched with MySQLdb 0.1.0; MySQL 3.22.29 on remote host), so I was running Zope with the same number of threads as there were connections, at the time of the hanging. My testing of Zope 2.1.6 is under these same conditions. I think the message of Jim Fulton's to which Michel refers is http://lists.zope.org/pipermail/zope/1999-December/015455.html Lately, I've seen reports of Zope restarting when manage_* is used; just to clarify, in my case Zope is not restarting: a single thread is hanging (deadlocked for some reason, perhaps?). This occurs in manage_* as well as on our live site, but only a single thread is affected at a time (other users could still log in while this thread was in its quiescent state. Michel Pelletier wrote: > I suspect this problem *might* be unrelated to the threadlock > discussed so far, in the case of the reported lock, 2 or more > threads cause instability. In your case, you report 4 is stable. Are you referring to the global python threadlock, or the ZODB lock to prevent conflict errors? Writes to ZODB are particularly infrequent, only occurring when I import changes. I'm trying to procure another similar machine for testing; unfortunately my personal machine's hard drive just packed up, so that's no good... If you have *any* suggestions as to where to start debugging (Pavlos Christoforou mentioned the async loop -- is that ZServer/medusa/asyncore.py?), please let me know. I'll start by slowly upping NUMBER_OF_THREADS until something screams. I'm really keen to get to the bottom of this... It's a pity we're about eight hours ahead of you down here in South Africa... Off to try grokking ZServer/*, -- Marcus

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ftp: get -R
by Marco Mariani 12 Apr '00

12 Apr '00

Wouldn't it be nice if zope supported the recursive get on ftp? Does anybody know how to edit through FTP with VIM? Thank you.

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Re: [Zope] Third Party Products 2nd Post
by Rik Hoekstra 12 Apr '00

12 Apr '00

-----Original Message----- From: Daniel G. Rusch <drusch(a)globalcrossing.com> To: zope(a)zope.org <zope(a)zope.org> Date: woensdag 12 april 2000 15:28 Subject: [Zope] Third Party Products 2nd Post >How does one install third party python products such as PIL or >ReportLab so that Zope's python interpreter can find it in it's path. > >I have installed both of these python products on a machine that has >python installed and not Zope and I have no problem using them. I am >trying to install them on my Zope machine so that I can using them in my >Zope site, but I can't seem to get Zope's python interpreter to find >them. > >Should I install them in the Extensions directory or where? How does one >set the Zope python path? Or is the evaluator stuck half way up. > The canonical way to do it is to install them in <zopehome>/lib/python/Shared, though other solutions have been thought up for PIL. Note, however, that they should be packages. Rik

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Third Party Products 2nd Post
by Daniel G. Rusch 12 Apr '00

12 Apr '00

How does one install third party python products such as PIL or ReportLab so that Zope's python interpreter can find it in it's path. I have installed both of these python products on a machine that has python installed and not Zope and I have no problem using them. I am trying to install them on my Zope machine so that I can using them in my Zope site, but I can't seem to get Zope's python interpreter to find them. Should I install them in the Extensions directory or where? How does one set the Zope python path? Or is the evaluator stuck half way up. Thanks, Dan

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Best way to run virtual web sites using Zope??
by Robert Geiger 12 Apr '00

12 Apr '00

I am interested in creating several web sites of the form Fire.mydomain.com Water.mydomain.com Earth.mydomain.com Sky.mydomain.com The "elements" are incidental! I would like to keep things on a single server. Can I do this?? It seems like Apache does this kind of thing, but I don't have much experience with it. The sites, BTW, do not necessarily have anything to do with each other and will probably be completely different so sharing and inheriting between sites is not a concern (unless it can be done!!) Thanks for your help. -- Robert Geiger robert(a)geigers.net

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