This is the next article in the series On the Way to Step Functions — you can find the first article in the series here. Previously, I have outlined the ambient desire in the field (marshalable stacks) and described why that is largely unachievable. But if imperative invocations can’t bid us consolation, what could? DAGs, in fact. If you are impatient (and a Rails user) - just head to the geneva_drive repo for the grand reveal.

The RubyLA blog offers insights, tutorials, and community updates for Ruby developers in Los Angeles and beyond. Developers can explore Ruby language features, web development frameworks, and best practices for building Ruby applications. Additionally, the blog covers Ruby meetups, events, and job opportunities in the Los Angeles area, fostering collaboration and networking within the local Ruby community.

RUBYLAND

Directed acyclic graphs (DAGs) provide a better foundation for durable execution systems than imperative code with marshalable stacks. By representing workflows as dependency trees rather than execution flows, DAGs enable checkpointing, idempotent computation, and parallel execution. Systems like Terraform and VFX software (Nuke, Blender) demonstrate this pattern in practice. Step-based workflows are actually a simplified subset of DAGs that sacrifice parallelism for easier implementation, while maintaining the ability to evolve into full DAG systems later.

On the way to step functions: it is actually a DAG