Re: Feature, conditionally started based on a system capability

[Sergiy Shyrkov <my...@gmail.com>]

Hello JB,

thank you for the prompt reply!

> You can to install the jahia-clustering feature only if  
> org.jahia.cluster "property" is activated, right ?
Yes, that's right (like a feature-switch or enabler).

I've corrected the syntax for the requirement and it is taken into  
consideration on the first installation of the feature.
I guess, my approach in having a feature dynamically be stopped or started  
based on a value of a property is just a wrong direction :-)

Right now I am having a working solution where I am just having a feature  
in the featuresBoot, as:

featuresBoot = \
     (bundle, \
     config, \
     deployer, \
...
     system, \
     wrap), \
     jahia-core, \
     jahia-jax-rs, \
     ${jahia.karaf.featuresBoot.extra}

And "jahia.karaf.featuresBoot.extra" system property is dynamically set by  
me (either to an empty string to to a "jahia-clustering").

For dynamically stopping/starting a feature on the property changes, I  
will do it manually in my code. Seems the right approach.

Thank you once again

Kind regards
Sergiy

On Fri, 29 Jan 2016 17:35:12 +0100, Jean-Baptiste Onofré <jb...@nanthrax.net>  
wrote:

> Hi Sergiy
>
> You can to install the jahia-clustering feature only if  
> org.jahia.cluster "property" is activated, right ?
>
> Did you try:
>
> <requirement>org.jahia.cluster;filter:=("activated=true")</requirement>
>
> (you don't need & in the LDIF syntax as you have only one test)
>
> and check if feature:requirement-list ?
>
> Thanks,
> Regards
> JB
>
> On 01/29/2016 05:22 PM, Sergiy Shyrkov wrote:
>> Hello,
>>
>> I would need some help/advice on the following use case, please (I am
>> new to Karaf).
>>
>> I would like to automatically have a feature be started, depending on
>> the availability of a system capability.
>> But I am not quite sure, I am taking a right approach.
>>
>> My feature, is related to clustering in our product and should be
>> activated or not, based on a Java system property.
>>
>> For now, I came up with the following system capability (which is
>> working so far):
>>
>> org.osgi.framework.system.capabilities= \
>> ...
>>   ${jahia-cluster-activated-${cluster.activated}}
>>
>> jahia-cluster-activated-false = org.jahia.cluster; activated="false"
>>
>> jahia-cluster-activated-true = org.jahia.cluster; activated="true"
>>
>>
>> And my feature is defined as follows (removing the unrelated stuff):
>>
>>      <feature name="jahia-clustering" version="${project.version}">
>>          <feature>cellar</feature>
>>
>> <requirement>org.jahia.cluster;filter:="(&amp;(activated=true))"</requirement>
>>
>>      </feature>
>>
>>
>> And here where I am stuck :-)
>> If I add my feature to the boot feature list (featuresBoot in
>> org.apache.karaf.features.cfg) I am getting a failure on Karaf startup
>> in case my system property cluster.activate=false:
>>
>> 2016-01-29 17:20:08,894 | ERROR | pool-21-thread-1 |
>> BootFeaturesInstaller            | 9 - org.apache.karaf.features.core -
>> 4.0.4 | Error installing boot features
>> org.osgi.service.resolver.ResolutionException: Unable to resolve root:
>> missing requirement [root] osgi.identity;
>> osgi.identity=jahia-clustering; type=karaf.feature;
>> version="[7.2.0.0-SNAPSHOT,7.2.0.0-SNAPSHOT]";
>> filter:="(&(osgi.identity=jahia-clustering)(type=karaf.feature)(version>=7.2.0.0-SNAPSHOT)(version<=7.2.0.0-SNAPSHOT))"
>> [caused by: Unable to resolve jahia-clustering/7.2.0.0-SNAPSHOT: missing
>> requirement [jahia-clustering/7.2.0.0-SNAPSHOT] org.jahia.cluster;
>> filter:="(&(activated=true))"]
>>      at
>> org.apache.felix.resolver.ResolutionError.toException(ResolutionError.java:42)
>>
>>
>>
>> And that prevents Karaf from starting.
>>
>> I have a feeling that I am using not the right solution for my use case
>> and would really appreciate any inputs / hints.
>>
>> Thanks in advance
>>
>> Kind regards
>> Sergiy
>>
>


-- 

Sergiy Shyrkov
Software Architect
jahia.com