how to do nested "with items" in orquesta?

[clindner85]

Hi all,

During execution of a workflow, I want to find out if another workflow is already running (avoid duplicates).
I can only find out if it is a duplicate by checking one of the child workflows.

Basically, I need to process the result from st2.executions.list action=my.workflow status=running
That may give me one or many executions where each execution has several "children" exec IDs listed.

In python, I would do something like:

"""Pseudocode"""
executions = st2.executions.list(action="my.workflow", status="running")
for parent in executions:
    for child in parent.children:
        # do something

How can I do such a nested for loop in orquesta using "with items"?

Would it be more effective and less complex to create a custom action and deal with this in python code?
Many thanks in advance!
Chris

[nzlosh]

To control workflow concurrency use Policies https://docs.stackstorm.com/reference/policies.html, since attempting to perform concurrency management from an action that checks St2 execution state will more than likely encounter unresolvable race conditions.

The is no concept of nesting with-items as per https://docs.stackstorm.com/orquesta/languages/orquesta.html#with-items-model, it's important to understand that results are not available per item iteration, but at the end of the with-item action in the form of a result list. So with-items behaves nothing like a python loop.

If the StackStorm concurrency model doesn't fit your needs, you may have to look at an external distributed locking system, be it your own or a third parties.

[clindner85]

Many thanks for the fast reply!
I'll check the policies and probably redesign my workflow accordingly.

[bertyah]

To piggy back on this response, is concurrency Policies something that would work for Rate limiting actions that reach out to APIs?