Stage conditional on success of a run result

[chrissimon-au]

I have a situation where it would be helpful to have a way to conditionally run a stage depending on the success of a run command (in my case, a grep).

I could just run the cmd, and if it fails, then the stage will fail, and I've had a look at using continueStageOnFailure which doesn't run the rest of the stage and move to the next stage - which is exactly what I want, but has a few issues:

• It prints an error message (which really it should be treated the same as when' false)
• other steps in the stage will not cause a pipeline failure if they fail, which they should

What it feels like I really need is something like whenRun which accepts the same arguments as run but which acts more like a when' command with the success result of the run being the when' argument.

I'm happy to take a look at opening a PR for this, but wanted to know first if you'd be happy to include it, and if you have any suggestions for implementation.

From a browse through the source it looks like it should go into ConditionsBuilder.fs. But there are quite a lot of _.run custom operations in StageBuilder in order to create all the possible uses of run - do I need to duplicate them all was whenRun variants, or is there an easier way you can see to achieve my goal?

[albertwoo]

@chrissimon-au PRs are welcomed.

whenRun is ok, but indeed it may duplicates alot of code. And not easy to extend.

What about when' with stage overload, for example:

pipeline "demo" {
   when' (stage "xxx" {
       run "xxxx"
   })
   ....
}

[chrissimon-au]

Interesting idea, yes that would work, and provide more flexibility around managing the run. So in my case, it would be something like:

pipeline "demo" {

   stage "always runs" {
      echo "always'
   }

   stage "sometimes runs" {
      when` (stage "condition" {
         run "grep content file"
      })

      echo "you'll only see this if the grep found something"
   }

   stage "later stage" {
      echo "always"
   }
}

This would even look nicer if the stage is set to a variable earlier, e.g.

let contentInFile = stage "content In File" {
    run "grep content file"
}

pipeline "demo" {

   stage "always runs" {
      echo "always'
   }

   stage "sometimes runs" {
      when` contentInFile

      echo "you'll only see this if the content was found in the file"
   }

   stage "later stage" {
      echo "always"
   }
}

Since it's the when' block it would be composable into whenAny, whenAll etc. - nice!

Let me see if I can work out how to add it... will submit a PR or come back with more questions :)