Re: [Zope-dev] Re: zcml entry points
Hey, On 10/20/07, Dieter Maurer [EMAIL PROTECTED] wrote: [snip] Zope 2 had (for products) all three things together. It was felt that this was a too tight coupling. Therefore, for Zope 3 the paradigma explicit is better than implicit (a paradigma, that I personally dislike and find wrong) was used. Now, you want again more things to happen implicitly. In my view, this is natural -- but not in the Zope 3 spirit... Sure, but while I fully acknowledge problems with the Zope 2 approach, in my view we've gone a bit overboard at times with the Zope 3 spirit. :) There is value in thinking about compact expression. The great benefit with Zope 3 is that we frequently actually *know* the aspects of what we want to express compactly, as we tend to be expressing these aspects separately. I hope we can foster a spirit where after we have factored out the independent aspects we can look at them again and make their expression more compact, at least for whatever we determine is a common case. Regards, Martijn ___ Zope-Dev maillist - Zope-Dev@zope.org 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] Re: zcml entry points
Martijn Faassen wrote at 2007-10-20 03:15 +0200: ... I'd say it is a general concern of a framework to try to avoid how often you need to repeat yourself. Right now you to use a Zope 3 package you need to do the following things: * list the egg in your setup.py dependencies * load the ZCML required * import it in your code Investigating ways to reduce this sounds like a win from a framework perspective. Getting rid of the separate ZCML step would help as it'd make it more similar to just reusing an arbitrary Python package, making Zope less special in some ways. Zope 2 had (for products) all three things together. It was felt that this was a too tight coupling. Therefore, for Zope 3 the paradigma explicit is better than implicit (a paradigma, that I personally dislike and find wrong) was used. Now, you want again more things to happen implicitly. In my view, this is natural -- but not in the Zope 3 spirit... -- Dieter ___ Zope-Dev maillist - Zope-Dev@zope.org 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] Re: zcml entry points
On Friday 19 October 2007 21:17, Martijn Faassen wrote: Tres Seaver wrote: I may not *want* the other package's ZCML to be loaded: some of its policies may not be appropriate for my application. +1. Happens to me all the time. Since this appears to be a rare case that is the exception, what about using the new ZCML exclude framework for this case? You need to know what you are doing, but this use case is for people who know exactly what they're doing anyway, right? -1. Regards, Stephan -- Stephan Richter CBU Physics Chemistry (B.S.) / Tufts Physics (Ph.D. student) Web2k - Web Software Design, Development and Training ___ Zope-Dev maillist - Zope-Dev@zope.org 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] Re: zcml entry points
Martin Aspeli wrote: Fred Drake wrote: On 10/17/07, Wichert Akkerman [EMAIL PROTECTED] wrote: A common issue we are seeing is that we have eggs depending on each other, but they still need to load the zcml from those dependencies somehow. As a temporary solution to play with the concept I added something simple to the plone.recipe.zope2instance buildout recipe. What's the problem you're seeing? I'm not sure what you're trying to solve. ZCML includes work just fine in the egg world. As long as you're referring to packaged ZCML using package=package.name in your include and includeOverrides directives, all is good. The main win, IMHO, is to avoid the requirement for people to install slugs for third party products. Slugs suck - they are confusing to explain and people forget them all the time. Buildout makes it a bit easier, but it's still not a terribly good solution. For example, say you want to install oi.plum. You need to add the line 'oi.plum' twice - once under 'eggs' and once under 'zcml' in your buildout.cfg. Forget the latter, and the package doesn't work properly (or at all). I see a different win. At the moment we are declaring dependencies in two places: in the egg information and in the zcml files. For every package I need I need to make sure its zcml is loaded, which means I need to have a meta.zcml, configure.zcml and overrides.zcml which load the meta, configure and overrides from all packages I depend on. I also need to inspect every package I depend on to check if they have a meta, configure or overrides.zcml, which in my humble opinion should be just an implementation detail that I, as someone who is just using the zope stack/framework, should not need to know about. Multiply that with the number of dependencies you see in zope.* and you see this becomes very unwieldy. So I turned things around: if I state in my egg information that I require another package that means I need to have that package available and functional. Which suggests that its zcml has to be loaded before mine. And that is exactly what I am doing: adding an entry point that allows a package to say in order to function I need to have these zcml files loaded. Wichert. -- Wichert Akkerman [EMAIL PROTECTED] It is simple to make things. http://www.wiggy.net/ It is hard to make things simple. ___ Zope-Dev maillist - Zope-Dev@zope.org 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] Re: zcml entry points
On Oct 17, 2007, at 8:04 PM, Ross Patterson wrote: ... I'm new to eggs, but maybe both sides could be satisfied with an approach like extra_requires? Extras are evil. See other posts of mine for explanations of why. You could list oi.plum [zope.zcml] when you require oi.plum *and* its ZCML and then it's ZCML would get loaded. Is this easily possible with eggs and/or buildout? easy_install has nothing to do with loading ZCML. A recipe could do something, but extra-requires don't help in any useful way. Jim -- Jim Fulton Zope Corporation ___ Zope-Dev maillist - Zope-Dev@zope.org 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] Re: zcml entry points
On Oct 18, 2007, at 8:17 AM, Tres Seaver wrote: I may not *want* the other package's ZCML to be loaded: some of its policies may not be appropriate for my application. I think that the library vs. pluggable application distinction is valid here: maybe you want to define an entry point in the egg which a given pluggable app would use at startup time to configure all the plugins which exposed that entry point. This probably an indication that there are two (I know, that horrible number) types of packages: - packages which provide zcml sugar in the form of new directive definitions - packages which perform component registrations It seems that packages which do only the former could be classified as a true library while the latter is more application-y. It seems like in a perfect world, libraries should not need any configure.zcml, just a meta.zcml which contains little except meta directives. Personally I think it would be more useful to remove policy-laden registrations from existing packages so they're more libraryish and move these registrations into site.zcml (or an entry point moral equivalent) than it would be to attempt to annoint the status quo as the right thing by implementing dependency graph traversal. - C ___ Zope-Dev maillist - Zope-Dev@zope.org 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] Re: zcml entry points
On 10/17/07, Martin Aspeli [EMAIL PROTECTED] wrote: The main win, IMHO, is to avoid the requirement for people to install slugs for third party products. Slugs suck - they are confusing to explain and people forget them all the time. Buildout makes it a bit easier, but it's still not a terribly good solution. Slugs are evil; agreed. We never use them. They were an accident of the instance tree inherited from older versions of Zope, and how that tree was re-interpreted for Zope 3. They never worked well, and did no one any favors. For example, say you want to install oi.plum. You need to add the line 'oi.plum' twice - once under 'eggs' and once under 'zcml' in your buildout.cfg. Forget the latter, and the package doesn't work properly (or at all). I actually really like this; I don't get the configuration for a package unless I ask for it. It's not unusual to want only the code and not the default configuration for a package. If we had entry points, we could just load the egg. Internally, oi.plum may use include / as much as necessary to load *its* dependencies, but that's not something the user of the package needs to worry about. Requiring a package doesn't say anything about how it's going to be used; making an assumption about that is really bad. If Zope loaded entry-point ZCML automatically (maybe with an on/off switch in zope.conf for those who need more fine grained control) that'd be a pretty nice solution. I suspect I'd always want it off. Picking up configuration willy-nilly is too dangerous. -Fred -- Fred L. Drake, Jr.fdrake at gmail.com Chaos is the score upon which reality is written. --Henry Miller ___ Zope-Dev maillist - Zope-Dev@zope.org 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] Re: zcml entry points
On 10/17/07, Martin Aspeli [EMAIL PROTECTED] wrote: Right - but you're building an application, and you're pretty experienced with Zope. A lot of Plone users just want to install a plug-in (a product), basically. Before, they just dropped it into a It sounds like your concerns center around users of a pluggable/extensible application (like Plone), rather than being general Zope concerns. It's certainly reasonable for an application to want a plugin architecture that works that way. Perhaps the development teams for the applications would be interested in getting together and sharing a package that supports a plugin architecture that works that way. That would be a good place to share effort without negatively impacting users who need bare-metal Zope or the developers of applications that don't have similar plugin-management requirements. -Fred -- Fred L. Drake, Jr.fdrake at gmail.com Chaos is the score upon which reality is written. --Henry Miller ___ Zope-Dev maillist - Zope-Dev@zope.org 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 )
