[Users] [GSOC][Gerrit] add potential reviewers - questions

Wed Mar 12 17:30:00 UTC 2014

On 03/12/2014 05:57 PM, Alon Bar-Lev wrote:
> 
> 
> ----- Original Message -----
>> From: "Itamar Heim" <iheim at redhat.com>
>> To: "Eli Mesika" <emesika at redhat.com>, users at ovirt.org
>> Cc: "Maor Lipchuk" <mlipchuk at redhat.com>, "Tomasz Kołek" <tomasz-kolek at o2.pl>, "infra" <infra at ovirt.org>
>> Sent: Wednesday, March 12, 2014 5:52:25 PM
>> Subject: Re: [Users] [GSOC][Gerrit] add potential reviewers - questions
>>
>> On 03/12/2014 04:57 PM, Eli Mesika wrote:
>>>
>>>
>>> ----- Original Message -----
>>>> From: "David Caro" <dcaroest at redhat.com>
>>>> To: "Itamar Heim" <iheim at redhat.com>
>>>> Cc: "Maor Lipchuk" <mlipchuk at redhat.com>, users at ovirt.org, "Tomasz Kołek"
>>>> <tomasz-kolek at o2.pl>, "infra"
>>>> <infra at ovirt.org>
>>>> Sent: Wednesday, March 12, 2014 11:01:21 AM
>>>> Subject: Re: [Users] [GSOC][Gerrit] add potential reviewers - questions
>>>>
>>>> On Wed 12 Mar 2014 08:16:02 AM CET, Itamar Heim wrote:
>>>>> On 03/11/2014 10:08 PM, Maor Lipchuk wrote:
>>>>>> On 03/11/2014 05:20 PM, Itamar Heim wrote:
>>>>>>> On 03/11/2014 05:14 PM, Eyal Edri wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>> ----- Original Message -----
>>>>>>>>> From: "Itamar Heim" <iheim at redhat.com>
>>>>>>>>> To: "Eyal Edri" <eedri at redhat.com>, "Tomasz Kołek"
>>>>>>>>> <tomasz-kolek at o2.pl>, users at ovirt.org, "infra" <infra at ovirt.org>
>>>>>>>>> Sent: Tuesday, March 11, 2014 5:10:54 PM
>>>>>>>>> Subject: Re: [Users] [GSOC][Gerrit] add potential reviewers -
>>>>>>>>> questions
>>>>>>>>>
>>>>>>>>> On 03/11/2014 05:06 PM, Ewoud Kohl van Wijngaarden wrote:
>>>>>>>>>> On Tue, Mar 11, 2014 at 10:37:22AM -0400, Eyal Edri wrote:
>>>>>>>>>>>> Tomasz Kołek wrote:
>>>>>>>>>>>>
>>>>>>>>>>>> I've got a few questions about project description.
>>>>>>>>>>>> Please tell me if my problem's understanding is good or not.
>>>>>>>>>>>> We need to add a few flags/methods to git review module. This
>>>>>>>>>>>> flags
>>>>>>>>>>>> should
>>>>>>>>>>>> allow to add potential reviewers in gerrit.
>>>>>>>>>>>> So:
>>>>>>>>>>>> Let's assume that we've got special flags for this operations.
>>>>>>>>>>>> What's
>>>>>>>>>>>> next?
>>>>>>>>>>>> 1. In gerrit system we need to add special place for potential
>>>>>>>>>>>> reviewers?
>>>>>>>>>>>> 2. Potential reviewers should agree that they want to review?
>>>>>>>>>>>> 3. We can have more than one accepted reviewer?
>>>>>>>>>>>
>>>>>>>>>>> I'm not sure i understood exactly what you mean by 'potential
>>>>>>>>>>> reviewers'.  do want gerrit (hook?) to automatically add reviewers
>>>>>>>>>>> to
>>>>>>>>>>> a patch according to the code sent?  so in fact you'll have a place
>>>>>>>>>>> somewhere for mapping code & specific developers?
>>>>>>>>>>
>>>>>>>>>> I really like this idea. Gerrit currently requires new users to know
>>>>>>>>>> who
>>>>>>>>>> to add as reviewers, IMHO impeding new contributors.
>>>>>>>>>>
>>>>>>>>>> One relative simple solution would be to look at who recently
>>>>>>>>>> touched
>>>>>>>>>> the files that are being modified and add them as reviewers. This
>>>>>>>>>> can be
>>>>>>>>>> done by looking at the git log for a file. Some pseudo python code
>>>>>>>>>> solution:
>>>>>>>>>>
>>>>>>>>>> reviewers = set()
>>>>>>>>>>
>>>>>>>>>> for modified_file in commit.files:
>>>>>>>>>>         reviewers += set(commit.author for commit in
>>>>>>>>>> git.log(modified_file))
>>>>>>>>>>
>>>>>>>>>> return reviewers
>>>>>>>>>>
>>>>>>>>>> This gives a system that those who touche a file, become the
>>>>>>>>>> maintainer
>>>>>>>>>> for that file. A more complex solution could improve on that and
>>>>>>>>>> limit
>>>>>>>>>> the reviewers added per patch. One can think of limiting to only
>>>>>>>>>> contributions in the last X months, weigh contributions so common
>>>>>>>>>> committers are prefered. It could also combine several methods.
>>>>>>>>>>
>>>>>>>>>> For example to limit to the 5 authors who touched the most files:
>>>>>>>>>>
>>>>>>>>>> reviewers = collections.Counter()  # New in python 2.7
>>>>>>>>>>
>>>>>>>>>> for modified_file in commit.files:
>>>>>>>>>>         reviewers += collections.Counter(commit.author for commit in
>>>>>>>>>>         git.log(modified_file))
>>>>>>>>>>
>>>>>>>>>> return [author for author, count in reviewers.most_common(5)]
>>>>>>>>>>
>>>>>>>>>> Since Counter also accepts a dictionary, one could also weigh the
>>>>>>>>>> touched lines per file. Downside there is big whitespace/formatting
>>>>>>>>>> patches can skew the line count.
>>>>>>>>>>
>>>>>>>>>> In short, I think an entire thesis could be written on the optimal
>>>>>>>>>> way
>>>>>>>>>> to determine reviewers but a simple algorithm could do to show the
>>>>>>>>>> method works.
>>>>>>>>>>
>>>>>>>>>> Does this help?
>>>
>>> Maybe it will be worth to use the information we have in Bugzilla here:
>>>
>>> We can browse the BZ that were closed/verified in the last XXX days
>>> Per BZ , we know which patches are involved, who reviewed the patches,
>>> which files were changed, when files were changed and the rank of the
>>> change (number of lines changed)
>>> I believe that from this information we can compose a simple ranking
>>> algorithm that its output will be a list of N potential reviewers for the
>>> patch.
>>> Since we can aggregate the above information for all files related to the
>>> patch we want to add reviewers, we can have this set for the whole patch.
>>> This information should be processed and stored each N days and gerrit will
>>> be able to use it.
>>
>> why are we trying to invent hueristics, instead of declaring clear
>> ownership?
> 
> Reminder: my source metadata plan that requires cooperation.
> 
> Each source and component should have an explicit ownership up into bug database.
> 
> I won't repeat it now, it is available at archives.
> 
I think we are discussing two different issues here:
The first one considers the GSOC project, of adding reviewers
automatically to a patch, this can be done in many different heuristics
depending what the submitter prefers (use blame, maintainers who acked
the patches, bugs, list of owners to a file and so on).

The second issue is adding and maintain a list of owners by
files/folders in oVirt.
this is a specific use case to be used by the "add potential reviewers"
project.

>>
>>>
>>>
>>>>>>>>>> _______________________________________________
>>>>>>>>>> Users mailing list
>>>>>>>>>> Users at ovirt.org
>>>>>>>>>> http://lists.ovirt.org/mailman/listinfo/users
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>> I think if we do this, we want to make sure we cover per file who is
>>>>>>>>> required to +2 it before we consider it acked.
>>>>>>>>>
>>>>>>>>
>>>>>>>> won't it require maintaining static lists of people per
>>>>>>>> file/path/project?
>>>>>>>>
>>>>>>>
>>>>>>> yes, but considering our project layout, i don't see an alternative.
>>>>>>> (some of the layout could be improved to be path based, rather than
>>>>>>> file
>>>>>>> based)
>>>>>> I think it could be done automatically by analysing the file and see who
>>>>>> mostly changed it recently, since the "owner" of the file might be
>>>>>> dynamic, who ever changed most of it few days ago might be more familiar
>>>>>> with it today
>>>>>>
>>>>>> IMO the algorithm of adding the reviewers should be flexible.
>>>>>> For example, using a folder which will contain files, where each file
>>>>>> implement an algorithm to add the reviewers.
>>>>>>
>>>>>> for instance we can have two files:
>>>>>> 1. Add a reviewers by blame - the contributor which changed recently the
>>>>>> code lines
>>>>>> 2. Add a reviewers by file - the contributor who changed most of the
>>>>>> file recently.
>>>>>>
>>>>>> Each file will implement the functional operation and will output the
>>>>>> reviewers emails.
>>>>>>
>>>>>> The user can then add a new algorithm or change it to be more specific
>>>>>> to its project.
>>>>>> for example the user can add also the maintainers which acked the patch
>>>>>> that was blamed.
>>>>>>> _______________________________________________
>>>>>>> Users mailing list
>>>>>>> Users at ovirt.org
>>>>>>> http://lists.ovirt.org/mailman/listinfo/users
>>>>>>
>>>>>
>>>>> this shouldn't be automatic. we need to clearly define ownership. we
>>>>> can't
>>>>> do
>>>>> this per repo for the engine/vdsm. we can do this per repo for the other
>>>>> repo's probably (though solving the folder/file approach would cover the
>>>>> simpler repos as a private case).
>>>>>
>>>>> yes, it will require some work, maybe some moving around of files to make
>>>>> this
>>>>> easier by folders (topics) which should be relevant anyway.
>>>>
>>>> I think it would easier to maintain if we just have one file at the
>>>> root, instead of having the ownership information distributed
>>>> throughout the files/directories. That way you'll know where to look at
>>>> to check/modify the ownership as opposed to having to walk all the
>>>> files and upper directories.
>>>>
>>>> Also, adding all that ownership logic to gerrit might not be easy, as
>>>> it's not meant to go checking the source of the repositories looking
>>>> for configuration. We might want to take a look (again) to zuul, the
>>>> tool that openstack uses as gateway to trigger jenkins jobs and merge
>>>> patches.
>>>>
>>>>> _______________________________________________
>>>>> Infra mailing list
>>>>> Infra at ovirt.org
>>>>> http://lists.ovirt.org/mailman/listinfo/infra
>>>>
>>>>
>>>>
>>>> --
>>>> David Caro
>>>>
>>>> Red Hat S.L.
>>>> Continuous Integration Engineer - EMEA ENG Virtualization R&D
>>>>
>>>> Email: dcaro at redhat.com
>>>> Web: www.redhat.com
>>>> RHT Global #: 82-62605
>>>>
>>>>
>>>> _______________________________________________
>>>> Infra mailing list
>>>> Infra at ovirt.org
>>>> http://lists.ovirt.org/mailman/listinfo/infra
>>>>
>>
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