| LPCIBot | Project windmill-devel build #151: STILL FAILING in 1 hr 8 min: https://lpci.wedontsleep.org/job/windmill-devel/151/ | 06:45 |
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| magcius | how did you guys hack apart zope so that you wouldn't have to use ZODB^W pickle? | 09:07 |
| wgrant | magcius: It basically just needs a custom publication class. | 09:08 |
| wgrant | I tried a similar thing in 2007 or so, and basically ended up copying the base publication and deleting ZODBish bits, and it worked fine. | 09:09 |
| wgrant | It wasn't practical to inherit much of it. | 09:09 |
| wgrant | Because ZODB is so ingrained. | 09:09 |
| wgrant | But it didn't end up that big, and that was the only thing to which I had to make significant changes, IIRC. | 09:09 |
| wgrant | I | 09:09 |
| wgrant | I may still have a copy of it around somewhere. | 09:09 |
| magcius | zope hacker I'm talking to says that must "wreak havoc on security" | 09:09 |
| wgrant | ... why? | 09:09 |
| wgrant | The security machinery doesn't depend on ZODB :/ | 09:10 |
| wgrant | That would be very Zope, but it's not true :) | 09:10 |
| magcius | "because the ZODB allows per object access control" | 09:10 |
| wgrant | That's got very little to do with ZODB. | 09:10 |
| wgrant | Security proxies work on Python objects. | 09:11 |
| wgrant | Not in the ZODB. | 09:11 |
| magcius | wgrant, can you point me to this code somewhere in LP? | 09:11 |
| wgrant | It'll be in lib/canonical/launchpad/webapp somewhere. | 09:12 |
| wgrant | canonical.launchpad.webapp.publication has our very custom publication. | 09:12 |
| wgrant | May also need custom RequestPublicationFactories. | 09:15 |
| wgrant | I forget where they live. | 09:15 |
| * wgrant greps. | 09:15 | |
| wgrant | Possibly not. | 09:19 |
| wgrant | Anyway, the critical bit is getApplication on the publication. | 09:19 |
| wgrant | You can see here it gets the ILaunchpadRoot utility. | 09:19 |
| wgrant | Rather than taking the root from a ZODB. | 09:19 |
| wgrant | There's also lovely.zetup which does ZODB and ZConfig removal, IIRC> | 09:20 |
| wgrant | But it's been a while :) | 09:21 |
| lifeless | wgrant: magcius: the problem is that zopes entire programming model is based around aozdb | 10:13 |
| lifeless | wgrant: magcius: so we're *still* paying for this hack in terms of performance | 10:13 |
| magcius | heh | 10:13 |
| magcius | if you could "do it again" today, what would you do | 10:14 |
| lifeless | well | 10:15 |
| lifeless | https://dev.launchpad.net/ArchitectureGuide/Services | 10:15 |
| lifeless | we are doing it again :) | 10:15 |
| lifeless | magcius: your zope hacker is right, it wreaks havoc | 10:17 |
| lifeless | magcius: it works, but its terribly terribly slow unless we're careful to preload things | 10:17 |
| lifeless | magcius: in terms of choosing an application stack, if we were setting out to do LP from scratch, I couldn't really say. | 10:19 |
| magcius | OK. | 10:19 |
| magcius | I'm getting into the scary world of web development here, and all the existing frameworks suck :( | 10:19 |
| wgrant | I don't like Django for this sort of thing. | 10:20 |
| wgrant | Zope sucks, but it is semi-appropriate for what LP is. | 10:20 |
| wgrant | Django is less appropriate IMO. | 10:20 |
| lifeless | I'd like to do something with http://liftweb.net/ | 10:20 |
| magcius | Here's what I like about Zope: the security/auth system is a bit neato, and I do like the interface and adapter system | 10:27 |
| lifeless | mmm | 10:27 |
| magcius | everything else? ZODB? meh. | 10:27 |
| wgrant | The security stuff is awesome, but is really slow with SQL. | 10:27 |
| lifeless | so I don't value those at all | 10:28 |
| magcius | lifeless, I like that you have to define users and roles and what can access what. | 10:28 |
| magcius | so that we don't get another diaspora :D | 10:28 |
| lifeless | they don't really fit in a hugely dynamic language like python | 10:28 |
| magcius | do you mean the auth system or z.i? | 10:28 |
| lifeless | z.i. | 10:29 |
| magcius | I assume you've read glyph's infamous post? | 10:29 |
| lifeless | ignoring some of the fugly globals based implementation details | 10:29 |
| lifeless | magcius: I think I have | 10:30 |
| magcius | I just treat z.i as a better isinstance right now | 10:30 |
| magcius | but not __subclasshook__. Because __subclasshook__ is all about trickery and deceit. | 10:30 |
| magcius | lifeless, http://glyph.twistedmatrix.com/2009/02/explaining-why-interfaces-are-great.html | 11:22 |
| lifeless | magcius: yes, that one | 11:37 |
| lifeless | magcius: basically, I think in python you want to embrace the duck | 11:38 |
| magcius | of course | 11:38 |
| magcius | z.i doesn't disallow or try to prevent that | 11:38 |
| magcius | but there are sometimes when you have an A, and you want a B | 11:39 |
| lifeless | I argue that using z.i. shows a failure to embrace the duck. | 11:39 |
| magcius | adaptation is perfect for that | 11:39 |
| lifeless | its *a* solution. | 11:39 |
| magcius | other solutions are isinstance | 11:39 |
| magcius | but isinstance is a bit closed... you have to modify the method if you want to add new types... | 11:39 |
| lifeless | isinstance, delegation, multimethods, type factories | 11:39 |
| magcius | etc etc. | 11:40 |
| lifeless | offhand | 11:40 |
| lifeless | there are probably other approaches too. | 11:40 |
| magcius | never heard of any of the latter | 11:40 |
| magcius | to make isinstance extensible, they added ABCs and __subclasshook__ | 11:40 |
| lifeless | yes | 11:40 |
| lifeless | this was a bit myopic. | 11:40 |
| magcius | which allows you to lie: you can say you're a B, even though you just look almost like a B | 11:41 |
| magcius | to me, that's the wrong way of doing it | 11:41 |
| lifeless | having a problem with isinstance, they made it worse :) | 11:41 |
| magcius | with z.i, you define what things you need in an interface, and then adaptation allows you to turn anything into what you need | 11:41 |
| magcius | instead of lying | 11:41 |
| lifeless | sure, if you don't mind the costs | 11:42 |
| lifeless | and the inflexability | 11:42 |
| lifeless | I dislike the costs and find the inflexability more a burden than a benefit, most of the time. | 11:42 |
| magcius | what costs do you see? | 11:42 |
| lifeless | its a global registry | 11:43 |
| lifeless | you run more code when importing your app | 11:43 |
| lifeless | You have to double-define everything | 11:43 |
| magcius | double-define? | 11:43 |
| lifeless | class IFoo(Interface): def foo():pass | 11:43 |
| magcius | you don't have to do that, although you should for documentation. | 11:44 |
| lifeless | class Foo(object): implements(IFoo); def foo(self): do stuff. | 11:44 |
| magcius | z.i won't check to make sure you're implementing everything | 11:44 |
| magcius | you can just do class IFoo(Interface): pass if you want | 11:44 |
| lifeless | magcius: you asked what the costs are. | 11:44 |
| lifeless | if you are writing in this style, this is something you do: its a cost. | 11:44 |
| magcius | OK, sure. | 11:44 |
| lifeless | magcius: we use interfaces very extensively in LP; I'm quite familiar with the system. | 11:45 |
| magcius | Right. | 11:45 |
| lifeless | I'm not arguing against it from a position of ignorance :) | 11:45 |
| magcius | I wish there was something that provided adaptation as a language feature. | 11:45 |
| lifeless | Oh, and I should add confusing-code to the list. | 11:46 |
| magcius | z.i code is extremely messy, z.c more so | 11:46 |
| lifeless | adaption is a poor way to write code, IMNSHO. | 11:46 |
| lifeless | i don't mean the implementation of z.i. is confusing : I mean that adaption centric code is confusing for readers. | 11:46 |
| magcius | if it was a Python language feature instead of ABCs, I would cheer. | 11:46 |
| magcius | but yeah | 11:47 |
| magcius | additionally, having to define roles and explicitly say "this is public" I like | 11:47 |
| lifeless | If IFloat and IString existed, when would you use "%3.4f" % foo and when would you use IString(foo), if foo is a float ? | 11:47 |
| magcius | those are dumb, though | 11:48 |
| magcius | IString isn't an interface. | 11:48 |
| magcius | what does it allow? | 11:48 |
| magcius | it would be ISequence or IMapping | 11:49 |
| lifeless | well, it would extend ISequence, | 11:49 |
| magcius | what does IString add on top of ISequence? | 11:49 |
| lifeless | actually IImmutableSequence | 11:49 |
| lifeless | magcius: replace, format, for starters | 11:50 |
| lifeless | magcius: join | 11:50 |
| magcius | I would expect IString(float(foo)) to be implemented in terms of a simple adapter: | 11:51 |
| magcius | def float_to_str(value): return str(value) | 11:51 |
| lifeless | this demonstrates the point. | 11:52 |
| lifeless | Thats approximately never the right way to convert a float to a string | 11:52 |
| magcius | well sure | 11:52 |
| lifeless | so having an adapter is bogus | 11:52 |
| magcius | str(float(value)) is as useless, though | 11:52 |
| lifeless | of course it is | 11:52 |
| * magcius kicks XChat | 11:52 | |
| magcius | ^W in XChat is "close tab" | 11:53 |
| magcius | I have no idea why... | 11:53 |
| magcius | If you're saying IString(foo) is stupid because str(foo) is stupid... | 11:54 |
| magcius | I don't see how this is an argument *against* interfaces or adaptation. | 11:54 |
| magcius | we already do the same thing with duck typing -- we don't care what it is, we just want a string out of it | 11:55 |
| magcius | str(foo) is the easy way to do this | 11:55 |
| lifeless | cast-based adaption is only useful when there is one and only one right way to get from A to B | 11:55 |
| magcius | of course. | 11:56 |
| magcius | for most types, there usually is only one way | 11:56 |
| lifeless | I disagree there. | 11:57 |
| lifeless | Perhaps 50%. Perhaps. | 11:57 |
| magcius | if there's a difference, you need to define a new interface IMHO | 11:57 |
| lifeless | I need to sleep | 11:57 |
| lifeless | I'll think more about how to articulate this. | 11:58 |
| magcius | if you have an IUser and you want an IAuthToken, going through an intermediate IPotato shouldn't effect the result. | 11:58 |
| lifeless | uhm | 11:58 |
| lifeless | I think you're talking about something different. | 11:59 |
| magcius | you go to bed. I will too. | 12:00 |
| lifeless | Noddy example. | 12:00 |
| lifeless | say you have ICar and IPassenger | 12:00 |
| lifeless | and a Car instance with 3 Passengers. | 12:00 |
| lifeless | Whats the behaviour of IPassenger(car) | 12:00 |
| magcius | it throws an error | 12:00 |
| magcius | or raises | 12:00 |
| lifeless | if there is an adapter present it won't. | 12:01 |
| lifeless | that doesn't make it useful. | 12:01 |
| magcius | the adapter throws an error | 12:01 |
| magcius | if there's more than one passenger :) | 12:01 |
| lifeless | if you do that, then you have code that will sometimes work and sometimes not. | 12:01 |
| magcius | realistically, this is the wrong use of adaptation | 12:01 |
| lifeless | See - when I see a right use of it, I will be happy. | 12:02 |
| magcius | in my code, all my use of interfaces is bascially 'isinstance' on steroids. | 12:02 |
| lifeless | I have *honestly* not seen a problem in python made simpler by using interfaces. | 12:02 |
| magcius | It's extremely, uh, method-based. | 12:02 |
| lifeless | magcius: using isinstance is a design problem in the first place. | 12:02 |
| magcius | lifeless, there are certain extreme cases where it is necessary. | 12:02 |
| lifeless | !cite | 12:03 |
| lifeless | :) | 12:03 |
| lifeless | I'm going to crash. Feel free to pick this up another time if you like. | 12:03 |
| magcius | OK | 12:04 |
| magcius | lifeless, http://paste.pound-python.org/show/TrBZVgWsMKEHo5EtQv8c/ | 12:08 |
| magcius | lifeless, you may say that's extreme edgecase... but this is what 90% of what my usage of z.i is | 12:09 |
| magcius | I would have to subclass if I wanted to add something else, and it quickly became messy. | 12:10 |
| magcius | so, I left a "hook". | 12:10 |
| lifeless | http://paste.pound-python.org/show/7357/ | 12:14 |
| lifeless | very quick-n-dirty | 12:14 |
| magcius | ... and it's failing to load | 12:14 |
| magcius | great | 12:14 |
| * magcius shoots _habnabit in the face. | 12:14 | |
| lifeless | I wouldn't normally do that, but am working on the assumption you can't fix your types ;) | 12:14 |
| lifeless | do you want me to paste it somewhere else? | 12:19 |
| lifeless | say so now cause *yawn* | 12:19 |
| * lifeless waves gnight | 12:21 | |
| LPCIBot | Project windmill-db-devel build #339: STILL FAILING in 1 hr 8 min: https://lpci.wedontsleep.org/job/windmill-db-devel/339/ | 17:14 |
| === issyl0_ is now known as Guest46812 | ||
| === Guest46812 is now known as issyl0 | ||
| LPCIBot | Yippie, build fixed! | 20:50 |
| LPCIBot | Project db-devel build #593: FIXED in 4 hr 55 min: https://lpci.wedontsleep.org/job/db-devel/593/ | 20:50 |
| LPCIBot | Project windmill-db-devel build #340: STILL FAILING in 1 hr 7 min: https://lpci.wedontsleep.org/job/windmill-db-devel/340/ | 23:58 |
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