AVD Store Azure Service Principal Credentials

<#
.SYNOPSIS
    Store Azure Service Principal credentials in an encrypted XML file.
.DESCRIPTION
    Store azure Service Principal credentials in an encrypted XML file, using the PowerShell Export-Clixml cmdlet.
.EXAMPLE
    Set-AzSPCredentials 
.CONTEXT
    Windows Virtual Desktops
.MODIFICATION_HISTORY
    Esther Barthel, MSc - 22/03/20 - Original code
    Esther Barthel, MSc - 22/03/20 - Standardizing script, based on the ControlUp Scripting Standards (version 0.2)

.LINK
    https://docs.microsoft.com/en-us/powershell/module/microsoft.powershell.utility/export-clixml?view=powershell-7 
    https://docs.microsoft.com/en-us/powershell/module/microsoft.powershell.utility/import-clixml?view=powershell-7
.NOTES
    Version:        0.1
    Author:         Esther Barthel, MSc
    Creation Date:  2020-03-22
    Updated:        2020-03-22
                    Standardized the function, based on the ControlUp Standards (v0.2)
    Updated:        2020-05-08
                    Created a separate Azure Credentials function to support ARM architecture and Az PowerShell Module scripted actions
    Purpose:        Script Action, created for ControlUp to support WVD monitoring
        
    Copyright (c) cognition IT. All rights reserved.
#>

# dot sourcing WVD Functions
[string]$mainformXAML = @'
<Window x:Class="wvdSP_Input_Form.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:Esther_s_Input_Form"
        mc:Ignorable="d"
        Title="Enter the WVD Service Principal (SP) details" Height="389.336" Width="617.103">
    <Grid>
        <TextBox x:Name="textboxTenantId" HorizontalAlignment="Left" Height="31" Margin="176,50,0,0" TextWrapping="Wrap" VerticalAlignment="Top" Width="398"/>
        <Label Content="SP Tenant ID" HorizontalAlignment="Left" Height="30" Margin="29,51,0,0" VerticalAlignment="Top" Width="117"/>
        <TextBox x:Name="textboxAppId" HorizontalAlignment="Left" Height="30" Margin="176,118,0,0" TextWrapping="Wrap" VerticalAlignment="Top" Width="398"/>
        <Label Content="SP App ID" HorizontalAlignment="Left" Height="30" Margin="29,118,0,0" VerticalAlignment="Top" Width="117"/>
        <PasswordBox x:Name="textboxAppSecret" HorizontalAlignment="Left" Height="31" Margin="176,192,0,0" VerticalAlignment="Top" Width="398"/>
        <Label Content="SP App Secret" HorizontalAlignment="Left" Height="30" Margin="29,193,0,0" VerticalAlignment="Top" Width="117"/>
        <Button x:Name="buttonOK" Content="OK" HorizontalAlignment="Left" Height="46" Margin="29,274,0,0" VerticalAlignment="Top" Width="175" IsDefault="True"/>
        <Button x:Name="buttonCancel" Content="Cancel" HorizontalAlignment="Left" Height="46" Margin="244,274,0,0" VerticalAlignment="Top" Width="175" IsDefault="True"/>

    </Grid>
</Window>
'@

Function Invoke-WVDSPCredentialsForm {
# Created by Guy Leech - @guyrleech 17/05/2020
    Param
    (
        [Parameter(Mandatory=$true)]
        $inputXaml
    )

    $form = $null
    $inputXML = $inputXaml -replace 'mc:Ignorable="d"' , '' -replace 'x:N' ,'N'  -replace '^<Win.*' , '<Window'
    [xml]$xaml = $inputXML

    if( $xaml )
    {
        $reader = New-Object -TypeName Xml.XmlNodeReader -ArgumentList $xaml

        try
        {
            $form = [Windows.Markup.XamlReader]::Load( $reader )
        }
        catch
        {
            Throw "Unable to load Windows.Markup.XamlReader. Double-check syntax and ensure .NET is installed.`n$_"
        }

        $xaml.SelectNodes( '//*[@Name]' ) | ForEach-Object `
        {
            Set-Variable -Name "WPF$($_.Name)" -Value $Form.FindName($_.Name) -Scope Global
        }
    }
    else
    {
        Throw "Failed to convert input XAML to WPF XML"
    }

    $form
}

function Get-AzSPStoredCredentials {
    <#
    .SYNOPSIS
        Retrieve the Azure Service Principal Stored Credentials.
    .DESCRIPTION
        Retrieve the Azure Service Principal Stored Credentials from a stored credentials file.
    .EXAMPLE
        Get-AzSPStoredCredentials
    .CONTEXT
        Azure
    .MODIFICATION_HISTORY
        Esther Barthel, MSc - 03/03/20 - Original code
        Esther Barthel, MSc - 03/03/20 - Standardizing script, based on the ControlUp Scripting Standards (version 0.2)
    .COMPONENT
        Import-Clixml - https://docs.microsoft.com/en-us/powershell/module/microsoft.powershell.utility/import-clixml?view=powershell-5.1
    .NOTES
        Version:        0.1
        Author:         Esther Barthel, MSc
        Creation Date:  2020-03-03
        Updated:        2020-03-03
                        Standardized the function, based on the ControlUp Standards (v0.2)
        Updated:        2020-05-08
                        Created a separate Azure Credentials function to support ARM architecture and Az PowerShell Module scripted actions
        Purpose:        Script Action, created for ControlUp WVD Monitoring
        
        Copyright (c) cognition IT. All rights reserved.
    #>
    [CmdletBinding()]
    Param()

    #region function settings
        # Stored Credentials XML file
        $System = "AZ"
        $strAzSPCredFolder = "$([environment]::GetFolderPath('CommonApplicationData'))\ControlUp\ScriptSupport"
        $AzSPCredentials = $null
    #endregion

    Write-Verbose ""
    Write-Verbose "----------------------------- "
    Write-Verbose "| Get Azure SP Credentials: | "
    Write-Verbose "----------------------------- "
    Write-Verbose ""

    If (Test-Path -Path "$($strAzSPCredFolder)\$($env:USERNAME)_$($System)_Cred.xml")
    {
        try 
        {
            $AzSPCredentials = Import-Clixml -Path "$strAzSPCredFolder\$($env:USERNAME)_$($System)_Cred.xml"
        }
        catch 
        {
            Write-Error ("The required PSCredential object could not be loaded. " + $_)
        }
    }
    Else
    {
        Write-Error "The Azure Service Principal Credentials file stored for this user ($($env:USERNAME)) cannot be found. `nCreate the file with the Set-AzSPCredentials script action (prerequisite)."
        Exit
    }
    return $AzSPCredentials
}

function Set-AzSPStoredCredentials {
    <#
    .SYNOPSIS
        Store the Azure Service Principal Credentials.
    .DESCRIPTION
        Store the Azure Service Principal Credentials to an encrypted stored credentials file.
    .EXAMPLE
        Set-AzSPStoredCredentials
    .CONTEXT
        Azure
    .MODIFICATION_HISTORY
        Esther Barthel, MSc - 22/03/20 - Original code
        Esther Barthel, MSc - 22/03/20 - Standardizing script, based on the ControlUp Scripting Standards (version 0.2)
    .COMPONENT
        Export-Clixml - https://docs.microsoft.com/en-us/powershell/module/microsoft.powershell.utility/export-clixml?view=powershell-5.1
    .NOTES
        Version:        0.1
        Author:         Esther Barthel, MSc
        Creation Date:  2020-03-22
        Updated:        2020-03-22
                        Standardized the function, based on the ControlUp Standards (v0.2)
        Updated:        2020-05-08
                        Created a separate Azure Credentials function to support ARM architecture and Az PowerShell Module scripted actions
        Purpose:        Script Action, created for ControlUp WVD Monitoring
        
        Copyright (c) cognition IT. All rights reserved.
    #>
    [CmdletBinding()]
    Param(
    )

    #region function settings
        # Stored Credentials XML file
        $System = "AZ"
        $strAzSPCredFolder = "$([environment]::GetFolderPath('CommonApplicationData'))\ControlUp\ScriptSupport"
        $AzSPCredentials = $null
    #endregion

    Write-Verbose ""
    Write-Verbose "------------------------------- "
    Write-Verbose "| Store Azure SP Credentials: | "
    Write-Verbose "------------------------------- "
    Write-Verbose ""

    If (!(Test-Path -Path "$($strAzSPCredFolder)"))
    {
        New-Item -ItemType Directory -Path "$($strAzSPCredFolder)"
        Write-Verbose "* AzSPCredentials: Path $($strAzSPCredFolder) created"
    }
    try 
    {
        Add-Type -AssemblyName PresentationFramework
        # Show the Form that will ask for the WVD Service Principal information (tenant ID, App ID, & App Secret)
        if( $mainForm = Invoke-WVDSPCredentialsForm -inputXaml $mainformXAML )
        {
            $WPFbuttonOK.Add_Click( {
                $_.Handled = $true
                $mainForm.DialogResult = $true
                $mainForm.Close()
            })
        
            $WPFbuttonCancel.Add_Click( {
                $_.Handled = $true
                $mainForm.DialogResult = $false
                $mainForm.Close()
            })
        
            $null = $WPFtextboxTenantId.Focus()
        
            if( $mainForm.ShowDialog() )
            {
                # Retrieve the form input (and check for errors)
                # tenant ID
                If ([string]::IsNullOrEmpty($($WPFtextboxTenantId.Text)))
                {
                    Write-Error "The provided tenant ID is empty!"
                    Exit
                }
                else 
                {
                    $tenantID = $($WPFtextboxTenantId.Text)
                }
                # app ID
                If ([string]::IsNullOrEmpty($($WPFtextboxAppId.Text)))
                {
                    Write-Error "The provided app ID is empty!"
                    Exit
                }
                else 
                {
                    $appID = $($WPFtextboxAppId.Text)
                }
                # app Secret
                If ([string]::IsNullOrEmpty($($WPFtextboxAppSecret.Password)))
                {
                    Write-Error "The provided app Secret is empty!"
                    Exit
                }
                else 
                {
                    $appSecret = $($WPFtextboxAppSecret.Password)
                }

                
                $appSecret = $($WPFtextboxAppSecret.Password)
        
                #Write-Output -InputObject "Tenant id is $($tenantID)"
                #Write-Output -InputObject "App id is $($appID)"
                #Write-Output -InputObject "App secret is $($appSecret)"
            }
            else 
            {
                Write-Error "The required tenant ID, app ID and app Secret could not be retrieved from the form."
                Break
            }
        }
    }
    catch
    {
        Write-Error ("The required information could not be retrieved from the input form. " + $_)
        Exit        
    }
        # Create the SP Credentials, so they are encrypted before being stored in the XML file
        $secureAppSecret = ConvertTo-SecureString -String $appSecret -AsPlainText -Force
        $spCreds = New-Object System.Management.Automation.PSCredential($appID, $secureAppSecret)

    try
    {
        $hashAzSPCredentials = @{
            'tenantID' = $tenantID
            'spCreds' = $spCreds
        }
        $AzSPCredentials = Export-Clixml -Path "$strAzSPCredFolder\$($env:USERNAME)_$($System)_Cred.xml" -InputObject $hashAzSPCredentials -Force
    }
    catch 
    {
        Write-Error ("The required PSCredential object could not be exported. " + $_)
        Exit
    }
    Write-Verbose "* AzSPCredentials: Exported succesfully."
    return $hashAzSPCredentials
}

# dot sourcing ControlUp Script Action settings
#region ControlUp Script Standards - version 0.2
    #Requires -Version 5.1

    # Configure a larger output width for the ControlUp PowerShell console
    [int]$outputWidth = 400
    # Altering the size of the PS Buffer
    $PSWindow = (Get-Host).UI.RawUI
    $WideDimensions = $PSWindow.BufferSize
    $WideDimensions.Width = $outputWidth
    $PSWindow.BufferSize = $WideDimensions

    # Ensure Debug information is shown, without the confirmation question after each Write-Debug
    If ($PSBoundParameters['Debug']) {$DebugPreference = "Continue"}
    If ($PSBoundParameters['Verbose']) {$VerbosePreference = "Continue"}
    $ErrorActionPreference = "Stop"
#endregion

#------------------------#
# Script Action workflow #
#------------------------#
Write-Output ""

## Retrieve input parameters

# Store the requested credentials in an encrypted file for future usage
If (Set-AzSPStoredCredentials)
{
    Write-Host ("The provided credentials are stored successfully for future references") -ForegroundColor Green
}
else 
{
    Write-Warning ("Unable to store the provided credentials")
}