March 2002 - Zope-Dev

manage frame change
by seb bacon 20 Mar '02

20 Mar '02

anyone object to changing the text at in the top ZMI frame to "Logged in as <user> on <machine>?" Or is there a better place to put that info? I find it useful when I've got several windows open to different servers. seb

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Restricting Sub-Objects in Folders DYNAMICALLY?
by Brian Oliver 19 Mar '02

19 Mar '02

I would like to restrict the types of objects (from a python-based product) that may be placed in Folders, or any other dumb container, based on certain conditions. For example: I'd like to restrict the number of a certain type of object that may appear in a folder. The end-user can add up to the limit, and afterwards the object type should NO LONGER APPEAR in the "Add List". I've thought about building a specialized folder, but I'd rather not. Zope already has a good folder with all the things I need. What Zope 2.4+ really needs to do is callback a provided function to determine if a particular class is allowed in a specified container instance (or class) Using the "implements" parameter of the registerClass method is not enough as it only permits static checking. Any help would be greatly appreciated. Regards -- Brian _________________________________________________________________ Send and receive Hotmail on your mobile device: http://mobile.msn.com

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Re: [Zope-dev] A thought for 2.6 about various leaks and memory problems
by Anthony Baxter 19 Mar '02

19 Mar '02

>>> "Adrian Hungate" wrote > moved to a different thread or earlier, before the fork, so that we could > simply kill senile threads without killing the entire shooting match? unfortunately apache does this with seperate processes, not threads. memory corruption and leaks aren't solved by offing threads, unfortunately. the equivalent would be to start a bunch of single threaded zeo clients on a machine, with a loadbalancer in front of them, and periodically off one. the only decent loadbalancers I've seen, however, are pretty heavy weight, flaky, limited in functionality, or some combination of all three. also, the start time for a new ZEO client is non-trivial. Anthony

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Impact of additional protocols handled by Zope?
by Jeff Kowalczyk 19 Mar '02

19 Mar '02

I'm curious what the impact on overall performance would be if products eventually came into existence that extended Zope to directly handle additional protocols and their data requirements, primarily intended for low-volume workgroup kind of traffic. Jabber, IMAP and LDAP are the ones that come to mind immediately, since you'd be that much closer to having Zope fulfill a role that MS Exchange really doesn't; inexpensive, easily maintained groupware for small organizations that need custom workflow app development. Is it practical to consider that Zope might extend into other protocols this way, and can it be done with modular products, or does integration require deep Zope modifications (beyond adding a few lines to Z2.py?) Just a hypothetical, I guess. FWIW, it would be really cool to see a general, host-a-protocol-here hook for plugin products as Zope3 takes shape, configuration in the ZMI if the product writer goes that far. Something that would define a standard interface for Zope3 events to respond to signals the protocol handler might generate, and vice-versa.

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Collector issue #30: Empty dates
by Lennart Regebro 19 Mar '02

19 Mar '02

http://collector.zope.org/Zope/30 What are people take on empty dates? Today I can find no way to enter empty dates (I think "None" worked before, but it doesn't work in 2.5.1b1 anyway). This is a problem, because we need to be able to have empty dates. Also, enetering something magick (like None, or 1980/0/0 isn't usable. We fix this with this simple patch, which so far has caused us no problems: from ZPublisher import Converters def fixedfield2date(v): from DateTime import DateTime if hasattr(v,'read'): v=v.read() else: v=str(v) if v=='': return v return DateTime(v) Converters.field2date = fixedfield2date Converters.type_converters['date'] = fixedfield2date It's the "if v=='': return v" part that does it. This makes it possible to enter empty strings as dates. We then handle these as unset dates. Seems to work fine as far as we can see. I was told that this had some type of compatibility issue. If thats the case, how do you suggest we fix it? Best Regards Lennart Regebro Torped Strategi och Kommunikation AB

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A thought for 2.6 about various leaks and memory problems
by Adrian Hungate 19 Mar '02

19 Mar '02

For the last few weeks (And maybe longer) I have been seeing lots of messages about zope leaking, the gc crashing and generally, Zope going senile after long runtimes or lots of requests. This was (And I believe still is) a problem for Apache, which they solved by having threads only live for a certain number of calls, then they die and are replaced by newly created threads. I know that with the current ZODB access model, this would be too slow, but is there any way that the opening of the ZODB could be moved to a different thread or earlier, before the fork, so that we could simply kill senile threads without killing the entire shooting match? I'll admit that I don't know enough about the core code to impliment this (And it is not solving the problem, only masking it) but it might be a good way for "the rest of us" to get back working on reliable Zope's while the core guys get the leaks located and plugged. Just a thought Adrian... -- The difficulty of tactical maneuvering consists in turning the devious into the direct, and misfortune into gain. - Sun Tzu

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Re: [Zope-dev] manage frame change
by Anthony Baxter 19 Mar '02

19 Mar '02

>>> seb bacon wrote > But we come back to the point that you may be logged into one of (say) 3 > app servers (ZEO clients) all serving the same domain, no? and on the same box ... :) Anthony

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more on the segfault saga
by Leonardo Rochael Almeida 18 Mar '02

18 Mar '02

<narrator voice="kosh">And so it continues...</narrator> I've finally recompiled all pythonScripts (all scripts and ZCatalog tricks I tried before didn't know how to get the PythonScripts inside the ZClasses. BTW, if anyone is interested, I can send you the scripts I used to recompile all pythonScripts inside ZClasses). But it still segfaults (and it doesn't seem to be any more stable, so there Anthony :-). At least I got a cleaner stupid_log_file, no more "needs recompilation" messages :-) Matthew, thanks for taking the time to gdb the beast with me. Did you come up with any instrumentation I should add to Python or Zope to get what it is that Python is trying to resease twice? If you want, I can arrange a MySQL-less period during production so that we can capture the crash in a cleaner environment. Speaking of instrumentation, since the gremlin seems to be threading related (it stops with '-t 1'), it might be useful to serialize certain parts of the execution path with semaphors, like the path to the restoration or the execution of PythonScripts, the path to the execution of SQL queries, etc. this means running with small locks in certain sections instead of the big '-t 1' lock (which is not really a lock, but you get the picture :-). Cheers, Leo -- Ideas don't stay in some minds very long because they don't like solitary confinement.

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Umask? On Windows 98? Ha!
by Lennart Regebro 18 Mar '02

18 Mar '02

I get this message when starting Zope 2.5.1b1 on Windows 98: 2002-03-18T19:32:15 INFO(0) z2 Your umask of 000 may be too permissive; for the security of your Zope data, it is recommended you use 077 That's rather silly on Windows 98. :-) A couple of questions: - Should that really be 077? That means that the owner can't read the files, but that "other" can! How can that be less permissive? 770 would make sense to me. I usually run z2.py with -u zope, and have zope own the files, and letting nobody else do scrap with them, 700, in other words. WHy would 077 be better? - Is it silly to check for Windows? What happens on Windows NT, does that emulate umask somehow, or do you get 000 there too?

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18 Mar '02

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