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From Christian Schneider <ch...@die-schneider.net>
Subject Re: [DISCUSS] Remove features lifecycle in K4
Date Tue, 14 Apr 2015 06:52:43 GMT
I was not aware we have this information in the wires. I will try to 
implement it using these.

So what I would do is this:
I start with the features to be stopped / started.
I then propagate down to the subfeatures / bundles.
For each feature processed I compute the state as the highest state of 
all features that depend on it and the requested state.

Does that make sense?

The problem in this algorithm is that in many cases we will not be able 
to stop features / bundles as they are needed by other features.
So probably we will need some reporting to explain why some features / 
bundles could not achieve the request state. To really stop a feature 
the user would then
have to stop all top level features. Only then would it really change 
its state.

We could also have kind of a force mode where we change the state first 
to the top and then down again. So this would guarantee that a feature 
changes its state but it could shut down half of karaf unintendedly. 
Which would be especially dangerous if we hit some core features like 
the feature service. So I tend to rather not support this.

Christian

On 13.04.2015 18:01, Guillaume Nodet wrote:
> Yeah, I was thinking about it.
> Though the obvious other solution is to fix it.
>
> I have actually started an email this morning to discuss but I haven't
> finished it.
>
> Overall, I think it may not be very difficult to fix, as the bundle state
> changes are already handled correctly afaik.  The real problem is to agree
> on the semantics on the effects, so that we can compute the desired state
> of each bundle correctly.
>
> Problems arise when a bundle is used by several features, one of which
> being started and the other resolved.
>
> Anyway, it's really up to you, I don't mind fixing the code as long as we
> agree on the behaviour.
>
> 2015-04-13 17:51 GMT+02:00 Jean-Baptiste Onofré <jb@nanthrax.net>:
>
>> Hi all,
>>
>> I discussed with Christian about KARAF-3102.
>>
>> The feature lifecycle doesn't actually fully work, especially around the
>> stop action.
>>
>> In order to avoid to perturb the users, I think we should remove the
>> features lifecycle commands. Else, if they are provided, users will try it
>> and may be disappointed as they won't work as expected.
>>
>> WDYT ?
>>
>> Regards
>> JB
>> --
>> Jean-Baptiste Onofré
>> jbonofre@apache.org
>> http://blog.nanthrax.net
>> Talend - http://www.talend.com
>>


-- 
Christian Schneider
http://www.liquid-reality.de

Open Source Architect
http://www.talend.com


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