Re: [wildfly-dev] selecting packages from feature-packs

> On Oct 21, 2016, at 10:03 AM, Brian Stansberry <brian.stansberry(a)redhat.com&gt; wrote: > > >> On Oct 21, 2016, at 9:20 AM, Alexey Loubyansky <alexey.loubyansky(a)redhat.com&gt; wrote: >> >> On 10/21/2016 03:50 PM, Brian Stansberry wrote: >>> >>>> On Oct 19, 2016, at 7:27 AM, Alexey Loubyansky <alexey.loubyansky(a)redhat.com&gt; wrote: >>>> >>>> Me and Stuart have been thinking about how to express feature-pack >>>> package selection in an XML. Each one came up with a proposal but we >>>> appear to have slightly different preferences. In case anybody has an >>>> opinion or a better suggestion, please, share. >>>> >>>> Brief description: feature-pack consists of packages. A package is a >>>> unit of content. So a set of packages determines the target installation >>>> content-wise. Feature-pack has a set of default packages. These are the >>>> packages that get installed by default, i.e. when the user installs the >>>> feature-pack w/o specifying any package preferences. In addition to the >>>> default ones a feature-pack may contains non-default packages, these are >>>> present in the feature-pack but will be installed only if the user >>>> explicitly asks for them. >>>> So, the question is how to express these package preferences in an XML. >>>> >>>> Proposal 1. >>>> >>>> - include-default flag (element or attribute) which defaults to true >>>> (meaning the default packages will be included by default); >>>> >>> >>> Th “include” element is still supported here, right? So, I can get all the default ones and then use include elements to pull in additional ones. >> >> Right. >> >>>> - if include-default is false (meaning nothing is installed by default), >>>> then 'include' element can be used to pick the specific packages >>>> (default and non-default ones) to be installed; >>>> >>>> - otherwise (when include-default is true) 'exclude' element can be used >>>> to exclude specific undesired default packages. >>>> >>> >>> Can “exclude” be used to exclude dependencies? So I want “a” but not its dependency “b”? If the answer is yes for optional dependencies, what if the dependency isn’t optional? >> >> Yes, it can be used to exclude dependencies. If a required (non-optional) dependency is excluded, that'll be an error. >> >>>> Proposal 2. >>>> >>>> - exclude element - applicable to any package and means do not install >>>> the package (and its dependencies); >>>> >>>> - include element - applicable to non-default packages and means do >>>> install the non-default package (and its dependencies); >>>> >>> What happens if it’s used for a default package? The tool forgives this, right? >> >> That would be redundant, of course. We could ignore that or issue a warning. > > That question was kind of a tangent. I asked because I could imagine a case where a package is not default in version 1, so the user adds an “include”. Then in a later version the package is now a default one. You don’t want to break the user for no good reason. > >> >>>> - pick element - applicable to any package and means install only the >>>> picked package(s) >>> >>> and it’s dependencies? If yes, all its dependencies or only non-optional? >> >> No, the dependencies would have to be picked explicitly. Otherwise, we have to allow exclude and include to be used in combination with pick which will look too confusing. >> > > Ok, then assuming that in Proposal 1 an “include” element always means pull in dependencies, I prefer Proposal 1. Forcing people to list everything just to get a subset of the default packages is painful and will likely break things if the feature-pack adds a new dependency in a later version. I realize my response didn’t account for the fact that in the Proposal 1 section you answered one of my questions by stating that excluding a non-optional dependency is an error. If the general rule is non-optional dependencies can’t be excluded, I see no reason why “pick” shouldn’t automatically bring them in. And then the only things a user would want to “exclude” in the context of a “pick” are optional dependencies. Which means always excluding them and forcing the user to include them via additional “pick” elements is less terrible. I still prefer Proposal 1, but not as strongly as I did. > > But… > > There are cases where people do want to explicitly list things and not have unexpected things brought in. See discussion on https://issues.apache.org/jira/browse/MNG-2315 (for which I voted). I do think it’s good to account for that kind of use case. > >>>> ignoring other default and non-default ones. pick >>>> cannot be used in combination with exclude and include. >>>> >>>> >>>> Basically, 'include' and 'exclude' in both proposals are practically the >>>> same. The difference is how the picking is expressed. In the first one, >>>> everything is explicitly excluded and then the desired ones are >>>> explicitly included, in the second one the desired ones are simply >>>> explicitly picked. >>>> >>> >>> The answers to my questions on Proposal 1 impact the semantics of include/exclude in different cases, so I’ll defer expressing an opinion for now. :) >> >> Thanks, >> Alexey >> >>> >>>> >>>> Thanks, >>>> Alexey >>>> _______________________________________________ >>>> wildfly-dev mailing list >>>> wildfly-dev(a)lists.jboss.org >>>> https://lists.jboss.org/mailman/listinfo/wildfly-dev > > -- > Brian Stansberry > Manager, Senior Principal Software Engineer > JBoss by Red Hat > > > > > _______________________________________________ > wildfly-dev mailing list > wildfly-dev(a)lists.jboss.org > https://lists.jboss.org/mailman/listinfo/wildfly-dev