OASIS Topology and Orchestration Specification for Cloud Applications (TOSCA) TC

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Re: [tosca] Custom Declarative workflows

  • 1.  Re: [tosca] Custom Declarative workflows

    Posted 10-29-2019 13:44
      |   view attached




    Hi Priya,  all,
     
    Following up from last meeting, please find attached a comparison between custom declarative workflows and their equivalent imperative workflows.
    Let s discuss this in the next meeting.
     
    BR,
    /Calin
     

    From: <tosca@lists.oasis-open.org> on behalf of Priya T G <priya.g@netcracker.com>
    Date: Tuesday, 15 October 2019 at 10:36
    To: Calin Curescu <calin.curescu@ericsson.com>, "tosca@lists.oasis-open.org" <tosca@lists.oasis-open.org>
    Subject: [tosca] Custom Declarative workflows


     

    Hi Calin,
     
    Thank you for the proposal on custom declarative workflows, I missed the discussions last week on this topic.
    Not sure if we are still debating on the need for custom declarative workflows or if  we have deep dived in to the proposal.

    We very much support the idea, a few comments/suggestions regarding the proposed approach:
     
     

    Can we add the possibility to describe this workflow not only in topology_template->workflows section, but also under node type:
     
    node_types:
       tosca.nodes.nfv.NS:
          derived_from: ...
          workflows:
             instantiate:
               description: custom declarative workflow that performs the entire startup sequence
               workflow_type: declarative
               node_types: [tosca.nodes.Root]
               follow_relationships: [tosca.relationships.Root]
               direction: target-to-source
               ....          

     
      topology_template:
      substitution_mappings:
            node_type: tosca.nodes.nfv.NS
     
     
    This enables the topology template that substitutes this node type to derive this workflow.
     
     
     
    2. Can we describe activities under a step definition instead of directly describing them under workflow definition, as highlighted in the snippet below:  
     
     
    workflows:
      startup:
        description: custom declarative workflow that performs the entire startup sequence
        workflow_type: declarative
        node_types: [tosca.nodes.Root]
        follow_relationships: [tosca.relationships.Root]
        direction: target-to-source
       
    steps :
          
    declarative_step:
               activities:
                   ....
     
     
    3. An observation: To align with TOSCA approach, it is more appropriate to describe
    direction: target-to-source 
     
    as
     
    direction:
    TARGET_TO_SOURCE
     
    Regards,
    Priya
     
     


    From: tosca@lists.oasis-open.org [mailto:tosca@lists.oasis-open.org]
    On Behalf Of Chris Lauwers
    Sent: Tuesday, October 15, 2019 10:57 AM
    To: tosca@lists.oasis-open.org
    Subject: [tosca] Agenda for 10/15/19 Language Ad-Hoc Meeting


     
    [External Email]



     



    Discuss feedback on Calin s declarative workflow proposal Language support for multiple instances



    Scaling of nodes Creating multiple node instances from the same node template Multiple requirements

     
    Chris

     



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    Attachment: custom_declarative_vs_imperative_workflows_examples.docx Description: custom_declarative_vs_imperative_workflows_examples.docx


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