[Yum] yum plugins: installonlypkgs, with wildcard matches

[Seth Vidal]

On Tue, 28 Jul 2009, Matt Savona wrote:

> Hi All,
> 
> I maintain a repository within my company of rubygems converted to RPMs. With respect to RPMs and Yum, these packages
> behave similarly to kernel packages, where some number of versions of a particular package can be installed on the system
> (the package files never overlap). For example, a system may have rubygem-mygem-1.0.0 and rubygem-mygem-1.0.1 installed
> in parallel.
> 
> The current repository contains about 16000 packages - and it's (obviously) not feasible for me to hard code this list of
> packages in /etc/yum.conf via the installonlypkgs option. What I really needed was the ability to drop a wildcard in the
> installonlypkgs list, something like 'installonlypkgs=rubygem-*'.
> 
> I came up with the following plugin, which I don't think is ideal - but it does the trick so far:
> 
> # ---
> # I should live here:
> # /usr/lib/yum-plugins/multiinstallpkgs.py
> 
> import re
> from yum import config
> from yum.plugins import TYPE_CORE
> 
> requires_api_version = '2.4'
> plugin_type = TYPE_CORE
> 
> def config_hook(conduit):
>     config.RepoConf.multiinstallpkgs = config.ListOption()
> 
> def postresolve_hook(conduit):
>     tsinfo = conduit.getTsInfo()
>     tspkgs = tsinfo.getMembers()
>    
>     def ysp_add_pkg(tspkg):
>         """ True installs a package within a transaction. """
>         tsinfo.addTrueInstall(tspkg.po)
>    
>     def ysp_del_pkg(tspkg):
>         """ Deletes a package within a transaction. """
>         tsinfo.remove(tspkg.pkgtup)
> 
>     for repo in conduit.getRepos().listEnabled():
>         for pkg in repo.multiinstallpkgs:
>             regex = re.compile("^" + pkg.replace("*", ".*") + "$")
> 
>             for tspkg in tspkgs:
>                 if (regex.match(tspkg.name) and tspkg.ts_state == "u"):
>                     ysp_del_pkg(tspkg)
>                     ysp_add_pkg(tspkg)
> # ---
> 
> This permits me to have a yum repo defined as:
> 
> [rubygems]
> name=Rubygem Repository
> baseurl=file:///path/to/yum/rubygems/rpms
> enabled=0
> gpgcheck=0
> multiinstallpkgs=rubygem-*
> 
> Which provides two minor improvements to the behavior of installonlypkgs: 1) it permits me to define what packages I want
> to be treated as install only via a repo config, rather than the main config, and 2) it permits me to define wildcard
> matches rather than supplying static package names.
> 
> What I'm not sure about is the way in which I modify the transaction - by removing and re-adding a package as a true
> install. I'm wondering, is there a better way? I noticed in depsolve.py, the populateTs method does the following:
> 
>     def allowedMultipleInstalls(self, po):
>         """takes a packageObject, returns 1 or 0 depending on if the package
>            should/can be installed multiple times with different vers
>            like kernels and kernel modules, for example"""
> 
>         if po.name in self.conf.installonlypkgs:
>             return True
> 
>         provides = po.provides_names
>         if filter (lambda prov: prov in self.conf.installonlypkgs, provides):
>             return True
> 
>         return False
> 
>     def populateTs(self, test=0, keepold=1):
>         """take transactionData class and populate transaction set"""
> 
>         for txmbr in self.tsInfo.getMembers():
>             if txmbr.ts_state in ['u', 'i']:
>                 if txmbr.ts_state == 'u':
>                     if self.allowedMultipleInstalls(txmbr.po):
>                         self.verbose_logger.log(logginglevels.DEBUG_2,
>                             _('%s converted to install'), txmbr.po)
>                         txmbr.ts_state = 'i'
>                         txmbr.output_state = TS_INSTALL
> 
> Is there a way to add my packages to conf.installonlypkgs before the transaction is populated? Or does it not matter,
> will the effect be the same as what I'm already doing? Or better yet, I know my case is relatively narrow, but would it
> maybe be feasible to support wildcard matching in installonlypkgs one day?
> 
> Thanks in advance!
>


First - I don't think it makes sense to have installonlypkgs per-repo - 
if only b/c it is impacts installed pkgs so it is not clearly a 
repo-thing. But that's not a big deal.

Secondly, why not have your plugin add items to installonlypkgs based on 
a wildcard and the nyou don't have to do anything in postresolve at all. 
installonlypkgs will mark them as trueinstalls on their own.

finally, 16000 installonly pkgs? Really? That sounds like a recipe for 
pain to me.

let me know if this doesn't make sense.
-sv