Include the URL of your launchpad blueprint:
Rather than working on the whole stack in-memory, in convergence we want to distribute tasks across workers by sending out notifications when individual resources are ready to be operated on.
The workflow has been prototyped in https://github.com/zaneb/heat-convergence-prototype/blob/resumable/converge/converger.py
After calculating the traversal graph, the stack update call triggers the leaf nodes of the graph. After each node is processed, examine the traversal graph (which is stored in the Stack table) to determine which nodes are waiting for this one. Store input data for each of those nodes in their SyncPoints, and trigger a check on any which now contain their full complement of inputs.
The SyncPoint for the stack works similarly, except that when complete we notify the stack itself to mark the update as complete.