How to nest Steps and Parallel with Hera Runner?

[bieniekmateusz]

Hi, I have a workflow that splits into smaller workflows multiple times.
I see that Steps used as a template is one way to breakdown the workflow. Is there any way to tackle nesting? e.g.

with Steps(...):
    with Parallel(...):
        with Steps(name="parallelA"):
            ...
        with Steps(name="parallelB"):
            ...

[flaviuvadan]

I think https://hera.readthedocs.io/en/stable/examples/workflows/steps/callable_steps/ might help! Argo supports nested invocations of templates but not definitions. In the above we have nested definitions of steps whereas in the example all the definitions are defined "at the top level" and invocations are performed in a nested manner

[flaviuvadan]

Something like

@script()
def foo(...): ...

with Workflow(...) as w
    with Steps(...).parallel() as a:
        foo(...)
        foo(...)
    
    with Steps(...).parallel() as b:
        foo(...)
        foo(...)

    with Steps(...).parallel() as main:
        a()
        b()

And ofc you can set input parameters to go from main to a and b