Powershell workflow function issue - powershell

Question

I´m trying to reuse code on my SMA runbooks but everything I try to put inside a function doesn´t seem to work as expected.
For example, If I do this it works and returns the username of the credential:
workflow RB_Test
{
$credent = Get-AutomationPSCredential -Name "CRED_TESTE"
$var = $credent.Username
"result = ${var}"
}
Output:
But if I turn into this it doesn't work anymore (returns null):
workflow RB_Test
{
function FN_Test
{
$credent = Get-AutomationPSCredential -Name "CRED_TESTE"
$var = $credent.Username
"result = ${var}"
}
FN_Test
}
Output:
I've tried different things but without success. The debug/verbose screen don't return anything different. That also doesn't work:
Inlinescript {
. FN_Test
}
My goal would be to put several functions into a separate module and then import it on my runbooks for reusability but this really seems not to work.
This is a runbook (powershell workflow) created in the Service Management Automation (SMA).
I've read that there are some restrictions with Powershell workflow compared to pure Powershell but I am not sure if I am hitting one of them:
https://blogs.technet.microsoft.com/heyscriptingguy/2013/01/02/powershell-workflows-restrictions/
Thanks

Answer 1

Here's what I've had to do to get functions to work:
workflow FunctionTest {
function log {
param(
[string]$Message
)
Write-Output $Message
Write-Output "Filename: $Filename"
Write-Output "using:Filename: $using:Filename"
Write-Output "workflow:Filename: $workflow:Filename"
Write-Output "----"
## Under what conditions is 'global' used? Can't be used in a workflow...Hey Scripting Guy!
}
workflow DoSomething {
param(
[string]$Filename
)
log "Starting DoSomething"
}
$Filename = "LogFile_2017.csv"
log "Starting workflow"
## Variables need to be passed into workflow from parent-workflow
DoSomething -Filename $Filename
log "End workflow"
}
FunctionTest
I found you need to define your functions before using them. The tricky part was discovering that you have to pass your variables into the child-workflow.
The scope of the variables takes some getting used to.