PowerShell 3.0 Workflow Secret Sauce

I was poking around in workflows and stumbled across this when I looked at a workflows definition and saw a large PowerShell scriptblock. I'm sure some of you will find this as interesting as I did. Actually, this explains a lot about workflows and how and why they behave the way they do. Enjoy!

Note: fu was the actual workflow name I used just to look at an empty defined workflow, e.g. workflow fu {}; then use this to see the properties of the workflow: gci function:fu | fl *

Below is what is in the ScriptBlock property.

[CmdletBinding()]
param (
[hashtable[]] $PSParameterCollection,
[string[]] $PSComputerName,
[ValidateNotNullOrEmpty()] $PSCredential,
[uint32] $PSConnectionRetryCount,
[uint32] $PSConnectionRetryIntervalSec,
[ValidateRange(1, 2147483)][uint32] $PSRunningTimeoutSec,
[ValidateRange(1, 2147483)][uint32] $PSElapsedTimeoutSec,
[bool] $PSPersist,
[ValidateNotNullOrEmpty()] [System.Management.Automation.Runspaces.AuthenticationMechanism] $PSAuthentication,
[ValidateNotNullOrEmpty()][System.Management.AuthenticationLevel] $PSAuthenticationLevel,
[ValidateNotNullOrEmpty()] [string] $PSApplicationName,
[uint32] $PSPort,
[switch] $PSUseSSL,
[ValidateNotNullOrEmpty()] [string] $PSConfigurationName,
[ValidateNotNullOrEmpty()][string[]] $PSConnectionURI,
[switch] $PSAllowRedirection,
[ValidateNotNullOrEmpty()][System.Management.Automation.Remoting.PSSessionOption] $PSSessionOption,
[ValidateNotNullOrEmpty()] [string] $PSCertificateThumbprint,
[hashtable] $PSPrivateMetadata,
[switch] $AsJob,
[string] $JobName,
[Parameter(ValueFromPipeline=$true)]$InputObject
)
begin {
function fu {
[CmdletBinding()]
param (
$PSInputCollection,
[string[]] $PSComputerName,
[ValidateNotNullOrEmpty()] $PSCredential,
[uint32] $PSConnectionRetryCount,
[uint32] $PSConnectionRetryIntervalSec,
[ValidateRange(1, 2147483)][uint32] $PSRunningTimeoutSec,
[ValidateRange(1, 2147483)][uint32] $PSElapsedTimeoutSec,
[bool] $PSPersist,
[ValidateNotNullOrEmpty()] [System.Management.Automation.Runspaces.AuthenticationMechanism] $PSAuthentication,
[ValidateNotNullOrEmpty()][System.Management.AuthenticationLevel] $PSAuthenticationLevel,
[ValidateNotNullOrEmpty()] [string] $PSApplicationName,
[uint32] $PSPort,
[switch] $PSUseSSL,
[ValidateNotNullOrEmpty()] [string] $PSConfigurationName,
[ValidateNotNullOrEmpty()][string[]] $PSConnectionURI,
[switch] $PSAllowRedirection,
[ValidateNotNullOrEmpty()][System.Management.Automation.Remoting.PSSessionOption] $PSSessionOption,
[ValidateNotNullOrEmpty()] [string] $PSCertificateThumbprint,
[hashtable] $PSPrivateMetadata,
[switch] $AsJob,
[string] $JobName,
[Parameter(ValueFromPipeline=$true)]$InputObject
) $PSBoundParameters
}
$PSInputCollection = New-Object 'System.Collections.Generic.List[PSObject]'
}
process {
if ($PSBoundParameters.ContainsKey('InputObject'))
{
$PSInputCollection.Add($InputObject)
}
}
end {
$parametersWithDefaults = @()
trap { break }
$parameterCollectionProcessed = $false
$PSParameterCollectionDefaultsMember = $null
if ($PSBoundParameters.ContainsKey('PSParameterCollection'))
{
foreach ($pa in $PSBoundParameters.Keys)
{
if ($pa -eq 'JobName' -or $pa -eq 'AsJob' -or $pa -eq 'InputObject' -or $pa -eq 'PSParameterCollection')
{
continue
}
$msg = [Microsoft.PowerShell.Commands.ImportWorkflowCommand]::InvalidPSParameterCollectionAdditionalErrorMessage;
throw (New-Object System.Management.Automation.ErrorRecord $msg, StartWorkflow.InvalidArgument, InvalidArgument, $PSParameterCollection)
}
$parameterCollectionProcessed = $true
foreach ($collection in $PSParameterCollection)
{
if ($collection['PSComputerName'] -eq '*' )
{
if ($PSParameterCollectionDefaultsMember -ne $null)
{
$msg = [Microsoft.PowerShell.Commands.ImportWorkflowCommand]::ParameterErrorMessage;
throw ( New-Object System.Management.Automation.ErrorRecord $msg, StartWorkflow.InvalidArgument, InvalidArgument, $PSParameterCollection)
}
$PSParameterCollectionDefaultsMember = $collection;
foreach($parameter in $parametersWithDefaults)
{
if(! $collection.ContainsKey($parameter))
{
$collection[$parameter] = (Get-Variable $parameter).Value
}
}
}
}
$PSParameterCollection = [Microsoft.PowerShell.Commands.ImportWorkflowCommand]::MergeParameterCollection(
$PSParameterCollection, $PSParameterCollectionDefaultsMember)
$PSParameterCollection = foreach ( $c in $PSParameterCollection) {
if($c.containskey('AsJob') -or $c.containsKey('JobName') -or $c.containsKey('PSParameterCollection') -or $c.containsKey('InputObject'))
{
$msg = [Microsoft.PowerShell.Commands.ImportWorkflowCommand]::InvalidPSParameterCollectionEntryErrorMessage;
throw ( New-Object System.Management.Automation.ErrorRecord $msg, StartWorkflow.InvalidArgument, InvalidArgument, $PSParameterCollection)
}
& "fu" @c
}
if (-not $PSParameterCollectionDefaultsMember)
{
foreach ($collection in $PSParameterCollection)
{
foreach($parameter in $parametersWithDefaults)
{
if(! $collection.ContainsKey($parameter))
{
$collection[$parameter] = (Get-Variable $parameter).Value
}
}
}
}
}
else
{
foreach($parameter in $parametersWithDefaults)
{
if(! $PSBoundParameters.ContainsKey($parameter))
{
$PSBoundParameters[$parameter] = (Get-Variable $parameter).Value
}
}
$PSBoundParameters = & "fu" @PSBoundParameters
}
if ($PSBoundParameters['PSCredential'])
{
$CredentialTransform = New-Object System.Management.Automation.CredentialAttribute
$LocalCredential = $CredentialTransform.Transform($ExecutionContext, $PSCredential)
$PSBoundParameters['PSCredential'] = [system.management.automation.pscredential]$LocalCredential
if (!$PSBoundParameters['PSComputerName'] -and !$PSBoundParameters['PSConnectionURI'])
{
$PSBoundParameters['PSComputerName'] = New-Object string @(,'localhost')
}
}
$jobName = ''
if ($PSBoundParameters['JobName'])
{
$jobName = $PSBoundParameters['JobName']
[void] $PSBoundParameters.Remove('JobName');
}
[hashtable[]] $jobSpecifications = @()
$parametersCollection = $null;
if ($PSBoundParameters['PSParameterCollection'])
{
$parameterSCollection = $PSBoundParameters['PSParameterCollection']
[void] $PSBoundParameters.Remove('PSParameterCollection');
}
if ($PSBoundParameters['InputObject'])
{
[void] $PSBoundParameters.Remove('InputObject');
}
$null = $PSBoundParameters.Remove('AsJob')
$null = $psBoundParameters.Remove('WarningVariable')
$null = $psBoundParameters.Remove('ErrorVariable')
$null = $psBoundParameters.Remove('OutVariable')
$null = $psBoundParameters.Remove('OutBuffer')
$psBoundParameters['PSWorkflowRoot'] = ''
try
{
$psBoundParameters['PSSenderInfo'] = $PSSenderInfo
}
catch
{
}
$psBoundParameters['PSCurrentDirectory'] = $pwd.Path
$myCommand = $MyInvocation.MyCommand
$myModule = $myCommand.Module
if ($myModule)
{
[Hashtable] $privateData = $myModule.PrivateData -as [Hashtable]
if ($privateData)
{
[hashtable] $authorMetadata = $privateData[$myCommand.Name]
if ($authorMetadata)
{
$authorMetadata = @{} + $authorMetadata
if ($psBoundParameters['PSPrivateMetadata'])
{
foreach ($pair in $psPrivateMetadata.GetEnumerator())
{
$authorMetadata[$pair.Key] = $pair.Value
}
}
$psBoundParameters['PSPrivateMetadata'] = $authorMetadata
}
}
}
if (! $PSBoundParameters['PSInputCollection'])
{
$PSBoundParameters['PSInputCollection'] = $PSInputCollection
}
$errorAction = "Continue"
if ($PSBoundParameters['ErrorAction'] -eq "SilentlyContinue")
{
$errorAction = "SilentlyContinue"
}
if($PSBoundParameters['ErrorAction'] -eq "Ignore")
{
$PSBoundParameters['ErrorAction'] = "SilentlyContinue"
$errorAction = "SilentlyContinue"
}
if ($PSBoundParameters['ErrorAction'] -eq "Inquire")
{
$PSBoundParameters['ErrorAction'] = "Continue"
$errorAction = "Continue"
}
$warningAction = "Continue"
if ($PSBoundParameters['WarningAction'] -eq "SilentlyContinue" -or $PSBoundParameters['WarningAction'] -eq "Ignore")
{
$warningAction = "SilentlyContinue"
}
if ($PSBoundParameters['WarningAction'] -eq "Inquire")
{
$PSBoundParameters['WarningAction'] = "Continue"
$warningAction = "Continue"
}
$finalParameterCollection = $null
if ($PSParameterCollection -ne $null)
{
$finalParameterCollection = $PSParameterCollection
}
else
{
$finalParameterCollection = $PSBoundParameters
}
try
{
$job = [Microsoft.PowerShell.Commands.ImportWorkflowCommand]::StartWorkflowApplication(
$PSCmdlet,
$jobName,
'ab0c05c8-c28f-48c7-97ea-915f34f4c0b8',
$AsJob,
$parameterCollectionProcessed,
$finalParameterCollection)
}
catch
{
$e = $_.Exception
if ($e -is [System.Management.Automation.MethodException] -and $e.InnerException)
{
$e = $e.InnerException
}
$msg = [Microsoft.PowerShell.Commands.ImportWorkflowCommand]::UnableToStartWorkflowMessageMessage -f `
$MyInvocation.MyCommand.Name, $e.Message
$newException = New-Object System.Management.Automation.RuntimeException $msg, $e
throw (New-Object System.Management.Automation.ErrorRecord $newException, StartWorkflow.InvalidArgument, InvalidArgument, $finalParameterCollection)
}
if (-not $AsJob -and $job -ne $null)
{
try
{
Receive-Job -Job $job -Wait -Verbose -Debug -ErrorAction $errorAction -WarningAction $warningAction
$PSCmdlet.InvokeCommand.HasErrors = $job.State -eq 'failed'
}
finally
{
if($job.State -ne "Suspended" -and $job.State -ne "Stopped")
{
Remove-Job -Job $job -Force
}
else
{
$job
}
}
}
else
{
$job
}
}

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PowerShell 3.0 Workflow Secret Sauce

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