Hi, in the last Vdsm developer call we agreed to promote a few modules in the common repository. The common repository provides the additional guarantees over regular modules in lib/vdsm/ - stable API - (thus) safe to use across verticals the planned moves are: lib/vdsm/schedule.py -> lib/vdsm/common/schedule.py

lib/vdsm/periodic.py -> lib/vdsm/common/periodic.py

lib/vdsm/virt/api.py -> lib/vdsm/common/api.py

Question is if those modules should go under common/ or under another subdirectory, maybe infra?

Lastly, i have a proposal about better handling of those modules. First, the mere fact a module is placed under lib/vdsm/common provides the extra guarantees I mentioned. But should we added more annotations? for example something like __API__ = {} near the top of the module if this attribute exist, then the module is safe to use across verticals, has stable API and so forth (this is _in addition_ to the common/ package, not as replacement). Like: __API__ = { "introduced-in": "4.14.0", "deprecated-from": "4.18.0", "removed-at": "4.20.0", "contact": "fromani(a)redhat.com" }

We could refine further this concept if we like it. The idea is to be lightweight as possible while carrying all the information we need.

Hi, in the last Vdsm developer call we agreed to promote a few modules in the common repository. The common repository provides the additional guarantees over regular modules in lib/vdsm/ - stable API - (thus) safe to use across verticals the planned moves are: lib/vdsm/schedule.py -> lib/vdsm/common/schedule.py lib/vdsm/periodic.py -> lib/vdsm/common/periodic.py lib/vdsm/virt/api.py -> lib/vdsm/common/api.py Question is if those modules should go under common/ or under another subdirectory, maybe infra?

Lastly, i have a proposal about better handling of those modules. First, the mere fact a module is placed under lib/vdsm/common provides the extra guarantees I mentioned. But should we added more annotations? for example something like __API__ = {} near the top of the module if this attribute exist, then the module is safe to use across verticals, has stable API and so forth (this is _in addition_ to the common/ package, not as replacement). Like: __API__ = { "introduced-in": "4.14.0", "deprecated-from": "4.18.0", "removed-at": "4.20.0", "contact": "fromani(a)redhat.com" } We could refine further this concept if we like it. The idea is to be lightweight as possible while carrying all the information we need.

Comments welcome as usual bests, -- Francesco Romani RedHat Engineering Virtualization R & D Phone: 8261328 IRC: fromani _______________________________________________ Devel mailing list Devel(a)ovirt.org http://lists.ovirt.org/mailman/listinfo/devel

On Tue, Mar 29, 2016 at 7:44 PM, Martin Polednik <mpolednik(a)redhat.com&gt; wrote: > On 29/03/16 11:12 -0400, Francesco Romani wrote: >> >> Hi, >> >> in the last Vdsm developer call we agreed to promote a few modules in the >> common repository. >> The common repository provides the additional guarantees over regular >> modules in lib/vdsm/ >> >> - stable API >> - (thus) safe to use across verticals >> >> the planned moves are: >> >> lib/vdsm/schedule.py -> lib/vdsm/common/schedule.py >> lib/vdsm/periodic.py -> lib/vdsm/common/periodic.py >> lib/vdsm/virt/api.py -> lib/vdsm/common/api.py >> >> Question is if those modules should go under common/ or under another >> subdirectory, maybe infra? > > > Hi. > > I agree that some modules should be kept (and advertised) as stable. > > The name 'common' is more suited for such package as 'infra' is very ovirt > specific and could hurt readability and navigation of the project. It does > make sense to structure the project as follows: > > lib/vdsm/common > lib/vdsm/virt/common > lib/vdsm/storage/common > lib/vdsm/network/common This creates a dependency between the packages. The goal is to have packages that do not depend on each other except the common package, which is library code used by other parts.

> Taking extra care taken to avoid 'common junkyard' situation and > making sure that the scope of common corresponds to it's package. > > List of modules that I consider public (mostly author/main contributor > of these lately): > > lib/vdsm/cpuarch.py > lib/vdsm/cpuinfo.py > lib/vdsm/hostdev.py > lib/vdsm/machinetype.py > lib/vdsm/numa.py > lib/vdsm/osinfo.py > lib/vdsm/udevadm.py +1 >> Lastly, i have a proposal about better handling of those modules. >> >> First, the mere fact a module is placed under lib/vdsm/common provides the >> extra guarantees I mentioned. >> But should we added more annotations? >> >> for example something like >> >> __API__ = {} >> >> near the top of the module >> >> if this attribute exist, then the module is safe to use across verticals, >> has stable API and so forth >> (this is _in addition_ to the common/ package, not as replacement). >> >> Like: >> >> __API__ = { >> "introduced-in": "4.14.0", >> "deprecated-from": "4.18.0", >> "removed-at": "4.20.0", >> "contact": &quot;fromani(a)redhat.com&quot; >> } >> >> We could refine further this concept if we like it. The idea is to be >> lightweight as possible while >> carrying all the information we need. > > > I agree about keeping global metadata in that way, except ideally > using docstrings for better readability (e.g. interactive help()). To > better reflect the needs for granular deprecation and based on our > private discussion on this subject, I'd like to see at least > @deprecated(target_removal_version) decorator. On top of that, we need > properly documented public API and deprecation process. Using standard way such as __author__ is better than docstrings, see for example the output of help(module)

Nir _______________________________________________ Devel mailing list Devel(a)ovirt.org http://lists.ovirt.org/mailman/listinfo/devel

----- Original Message ----- > From: "Nir Soffer" <nsoffer(a)redhat.com&gt; > To: "Francesco Romani" <fromani(a)redhat.com&gt; > Cc: "devel" <devel(a)ovirt.org&gt; > Sent: Tuesday, March 29, 2016 6:00:56 PM > Subject: Re: [ovirt-devel] [vdsm] new internal stable modules + proposal [...] > > Lastly, i have a proposal about better handling of those modules. > > > > First, the mere fact a module is placed under lib/vdsm/common provides the > > extra guarantees I mentioned. > > But should we added more annotations? > > > > for example something like > > > > __API__ = {} > > > > near the top of the module > > > > if this attribute exist, then the module is safe to use across verticals, > > has stable API and so forth > > (this is _in addition_ to the common/ package, not as replacement). > > > > Like: > > > > __API__ = { > > "introduced-in": "4.14.0", > > "deprecated-from": "4.18.0", > > "removed-at": "4.20.0", > > "contact": &quot;fromani(a)redhat.com&quot; > > } > > Since this is internal api, I don't think we need this info. The > guarantee you have when you > use such module is that it will never break your code. If someone one > is changing such module, > it must change and test the code using it. > > Maybe the "standard" __author__ ? Yes, maybe just __author__ , __deprecated__ and perhaps __status__. I think __deprecated__ would be fit for the task.

(take from e.g. http://stackoverflow.com/questions/1523427/what-is-the-common-header-form... ) -- Francesco Romani RedHat Engineering Virtualization R & D Phone: 8261328 IRC: fromani _______________________________________________ Devel mailing list Devel(a)ovirt.org http://lists.ovirt.org/mailman/listinfo/devel