[PATCH 1 of 4 RFC] hook: have a generic hook for transaction opening

[Pierre-Yves David]

On 03/10/2015 06:04 AM, Augie Fackler wrote:
> On Tue, Mar 10, 2015 at 01:14:28AM -0700, Pierre-Yves David wrote:
>>
>>
>> On 03/10/2015 01:07 AM, Pierre-Yves David wrote:
>>> # HG changeset patch
>>> # User Pierre-Yves David <pierre-yves.david at fb.com>
>>> # Date 1418264389 28800
>>> #      Wed Dec 10 18:19:49 2014 -0800
>>> # Node ID 82dea52f27319896a8d33a0b805f439107a94845
>>> # Parent  4ef4e3c3c00693868ba428e21ac092e559e4fcea
>>> hook: have a generic hook for transaction opening
>>
>> This is RFC because I'm unhappy with the current names, but they are going
>> to be bikesheded anyway. So I would like to get the topic moving and code is
>> a good way to get that.
>>
>> The name in this series are:
>>
>> - txnopen (can abort)
>> - txnclosing (can abort)
>> - txnclosed
>
> I have no particular recommendations for better names (sorry), but I'm
> not sure what the merit of txnopen is given that we can't provide much
> information. A sample use case would help there, I guess.

I've no sample usecase for txnopen, but it is very cheap to add and I 
guess some extension//baroque setup will be very happy to have some 
official way to control//record transaction opening.

We could also move it a bit further to right after the transaction have 
been openened (or add a new hooks for that). So that its easy to add 
data in the transaction after it is open.

Maybe we should have a hook for aborted transaction too. But yet again 
I've no specific usecase in mind.

> As for the others, we could probably rework some existing
> functionality to be examples. verify-after-push could be done as a
> txnclosing, and txnclosed could be used by the notify extension, so I
> see merit in both of those.

txnclosing and txnclosed are -must-have-. None of the current hook allow 
to catch a full transaction run with all its data. This is extremely 
annoying for validation or synchronization.

-- 
Pierre-Yves David