[Rock-dev] Using a specific task deployment in a composition (Roby)

[Chris Müller]

 From the view point of roby, its compeletely no problem, because each task is referenced by the role name for
configuration. But i guess there could occur some problems with the filenames of the log data, whose names are declared
by the deployment definitions (by orogen).

If no explicit mapping from the providing pool of tasks by the deployments is given, roby is probably
deciding itself, which task is used as long as it has the correct task type. If you have more than one
tasks of a given task type, it could be e.g. the task 'sonar_rear'
(the name defined in the deployment) is used for 'sonar_front'.
But can be referenced in roby via the role 'sonar_rear'.

I haven't met yet such a problem with our log datas, but i wouldn't exclude this constellation.



23.05.2012 10:40, Janosch Machowinski wrote:
> Hi Chris,
> why do you actually need to nail a task to a
> deployments ? If it is only about the configuration,
> you can do this like this :
> add(Cmp::DualSonar.use('sonar' =>
> SonarTritech::Micron.with_conf(''default', 'foo'), 'sonar_rear' =>
> SonarTritech::Micron.with_conf(''default', 'rear')))
> Greetings
>       Janosch
> On 21.05.2012 16:35, Chris Müller wrote:
>> Hi,
>>
>> Thomas has asked me about an interesting use case in defining a
>> composition in roby. Here is a simplified description about the problem.
>> Assume the following setup:
>>
>> # deployments
>> simple_deployment("sonar", "sonar_tritech::Micron")
>> simple_deployment("sonar_rear", "sonar_tritech::Micron")
>>
>> # compositions
>> composition 'DualSonar'
>>        add SonarTritech::Micron, :as =>   'sonar'
>>        add SonarTritech::Micron, :as =>   'sonar_rear'
>> end
>>
>> The final question is how can we map the Micron task from deployment
>> "sonar" directly
>> to place holder for the 'sonar' task in the DualSonar composition.
>>
>> On our AUV Avalon we have a similar use case, where we distinguish two
>> sonar devices from the same driver and it seems it maps magically in the
>> correct order. (never met any problem by roby).
>>
>> I don't know if the :as flag is influencing the mapping mechanism for
>> the right deployment or only the order of deployment declarations is
>> relevant.
>>
>> In the experiments it wouldn't be a problem because each task in the
>> composition is configured through the :as identifier. But after a few
>> thoughts i would currently not exclude a situation where the deployment
>> "sonar" is configured and used for the "sonar_rear" task.
>>
>> Does anyone have some more experiences with this use case? (Matthias,
>> Janosch?)
>>
>> Chris
>>
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>