Representing conditional execution

[simleo]

How should we model workflows where one or more steps are executed only if a condition is verified (e.g., when clause in CWL)?

[mr-c]

Sine this RO-Crate profile is about a particular enactment of a workflow, then it might be simpler to not model the condition.

As a bonus, I guess one could record the decision to skip a step. For CWL that would require the CWL document and the input object for that workflow step, then one could investigate the JavaScript statement that was evaluated and found to produce a False (== skip) result. For CWL steps that weren't skipped, the step input object should already be represented allowing a similar analysis post-run of the decision by a human evaluating the JavaScript statement.

[GlassOfWhiskey]

This is related to #15. However, there is no SkippedActionStatus on schema.org. Maybe we need another field? Or we can use the PotentialActionStatus with that meaning?

[stain]

It depends on the workflow language if conditional execution means the step is run or the datalink is rewired - presumably some evaluation happens though. Is that part of the ControlAction with no tool invocation?

Or would it be an AssessAction that could end up with either subclass IgnoreAction or ChooseAction? Might get quite elaborate as you would then as object of those have what was evaluated rather than what inputs were potentially going to be used.

{
  "@context": "https://schema.org",
  "@type": "IgnoreAction",
  "agent": {
    "@type": "Person",
    "name": "John"
  },
  "object": {
    "@type": "BefriendAction",
    "agent": {
      "@type": "Person",
      "name": "Steve"
    },
    "instrument": {
      "@type": "WebPage",
      "url": "https://www.social.com"
    }
  }
}

[simleo]

StreamFlow is already using PotentialActionStatus

[simleo]

In CWLProv, skipped actions are not recorded. Hence, in runcrate convert, the tool / subworkflow is listed in the prospective provenance but there is no corresponding action in the retrospective provenance. See ResearchObject/runcrate#45, which adds an example where a subworkflow is skipped. The approach there is to list the subworkflow and the corresponding step in the crate, but no corresponding action (like in CWLProv).

[simleo]

StreamFlow is already using PotentialActionStatus

I ran the workflow used to test ResearchObject/runcrate#45 with Streamflow (0.2.0.dev5) and generated the RO-Crate: it turns out that it does not add an action with PotentialActionStatus. Instead, it behaves like runcrate after the merging of ResearchObject/runcrate#45 (subworkflow and step are listed, but no corresponding action).

[stain]

TRE-FX also have execution states https://trefx.uk/5s-crate/0.4/#execution-states - but for the overall workflow. e.g. http://schema.org/ActiveActionStatus if it's still running. In theory if someone was doing similar execution steps for a workflow that is not yet finished, then some of those would be in PotentialActionStatus until it's not executed. You would need to add something like a https://schema.org/IgnoreAction control action show that the step was later NOT picked so it would get complicated. So I would support #70 for its simplicity.