Hi Calin,
Thanks for putting this together. I’ve been thinking about the same problem (how to automatically generate workflows when nodes and/or relationships use non-normative Interface types). However, I’ve been pursuing a slightly different approach:
- My approach tries to extend the Interface Type definitions themselves with additional information about the “state machine” implemented by the interface. This could be accomplished
by moving some of the Workflow definition constructs into Interface Type definitions:
- What is the order in which operations must be called? This could be expressed using the same “preconditions” concept we’re currently using in Workflow definitions
- What is the state into which the node/relationship transitions as a result of successful execution of the operation? Again, this can be expressed using the same “set_state” constructs
that are currently using in Workflow definitions.
- By extending interface type definitions, an orchestrator could automatically construct the proper sequence of steps for individual nodes. However, we also need to specify the sequencing
between nodes. This could again be done by leveraging the “preconditions” construct, where certain operations cannot be performed until the relationships in and out of the nodes are in certain states. However:
- How can this be done without making assumptions about the Interface Types used by those relationships?
- How can this be done without making assumptions about the number of relationships exist in and out of each node?
This is where some of the constructs you’re proposing could be helpful.
I’ll try to more formally present the beginnings of my approach over the next week or so, and perhaps we can work together on getting this finalized.
Thanks,
Chris
From: tosca@lists.oasis-open.org <tosca@lists.oasis-open.org>
On Behalf Of Calin Curescu
Sent: Tuesday, October 30, 2018 6:51 AM
To: tosca@lists.oasis-open.org
Subject: [tosca] Groups - Specifying custom declarative workflows in TOSCA uploaded