[openstack-dev] [Mistral] Understanding parameters for tasks and actions

Nikolay Makhotkin nmakhotkin at mirantis.com
Wed Feb 26 08:32:51 UTC 2014


Timur, '$' here is mean referrence to context at stage which it has been
given to.

'$.image_id' takes 'image_id' from current workflow execution context
variable


On Wed, Feb 26, 2014 at 12:30 PM, Nikolay Makhotkin <nmakhotkin at mirantis.com
> wrote:

> Hi, Renat!
>
>
>
> *Suggestions*
>> *1*. Define "input" and "output" at task level like this:
>>      createVM:
>>        input:
>>          image_id: $.image_id
>>        output: vm_id
>> Where "output: vm_id" is basically a replacement for "store-as: vm_id" at
>> action level, i.e. it's a hint to Mistral to store the output of this task
>> under "vm_id" key in execution context. Again, the idea is to define task
>> and action responsibilities more strictly:
>>
>>    - *Task is a high-level workflow building block which defines
>>    workflow logical step and how it modifies workflow data. Task doesn't
>>    contain technical details on how it's implemented.*
>>
>>
>>    - *Action is an implementor of the workflow logical step defined by a
>>    task. Action defines specific algorithm of how task is implemented.*
>>
>>
>> *2*. User "parameters" only for actions to specify their additional
>> properties influencing their nature (like method for HTTP actions).
>
>
> Just clarify your thoughts:
>  - All static keys and parameters should be in actions
>  - All dynamic keys and parameters should be in tasks block
>  - We may use our context to define some parameters in action or task
>
> And, yes, I think it is a good idea to differentiate this. It is become
> easier
>



-- 
Best Regards,
Nikolay
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