Capturing user input from a powershell workflow

Question

I have the following:

Workflow Test {
    $message = "Hey"
    InlineScript{
        Write-Output $using:message
        Read-Host 'Get user input before proceeding.'
    }
    InlineScript{
        Write-Output $using:message
    }
}

Test

What I get in return:

A command that prompts the user failed because the host program or the command type does not support user interaction.

Is there any way to tell a workflow to pause for user input before proceeding? I'm using Workflows to support parallel foreach - but I want to pause between operations.

I could try this:

Workflow Test1 {
    $message = "Hey"
    InlineScript{
        Write-Output $using:message
        Read-Host 'Get user input before proceeding.'
    }
}

Workflow Test2 {
    $message = "Hey"
    InlineScript{
        Write-Output $using:message
    }
}

Test1
// wait for user input
Test2

But then I have repeated constants there - $message - which isn't very DRY.

I'm fairly certain that this isn't possible. Workflows can be triggered "interactively" but are expected to be run non-interactive, and often against a number of different machines all at once. The reason you even need InlineScript to support all PowerShell commands is because it's a different environment, so you can think of those blocks as running in a different runspace. — briantist
– briantist, Commented Aug 10, 2016 at 20:33
@briantist - I see. I guess I could do separate workflows, but then I have to repeat all of my variable declarations in every single one, which seems really messy. Any tips on this? Updating question now. — RobVious
– RobVious, Commented Aug 10, 2016 at 20:50
If the only reason you're using a workflow is for parallelism, I'd recommend just using jobs or PoshRsJob. — briantist
– briantist, Commented Aug 10, 2016 at 20:51

Bernie White · Accepted Answer · 2016-08-10 22:25:38Z

2

A PowerShell Workflow is designed to run without interaction. Each workflow is scheduled as a job that runs in a seperate PowerShell instance.

Workflows are designed to be robust and parallel, and allowing input from a person in the middle of a workflow would increase the risk of something going wrong in the middle of execution.

You can pass parameters into a workflow by using the normal param keyword, which would allow you to get any information you need to execute the workflow up front.

workflow DoStuff
{
    param([string[]]$Value)

    ...
}

Another way to not require interactivity would be think about how you could detect when PowerShell should move on to the next operation instead of requiring a person to.

edited Aug 10, 2016 at 22:25

answered Aug 10, 2016 at 22:20

Bernie White

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