ConvertTo-DSC

<#
.Synopsis
   ConvertTo-DSC allows you to get registry keys and values configured in existing GPOS
   and use that information to create DSC docuemnts.
.DESCRIPTION
   Group Policy Objects have been created, managed, configured, re-configured, deleted,
   backed up, imported, exported, inspected, detected, neglected and rejected for many years. 
   Now with the advent of Desired State Configuration (DSC) ensuring that the work with regards 
   to configuring registry policy, is not lost. ConvertTo-DSC is a cmdlet (advanced function) 
   that was created to address this sceanario. The ConvertTo-DSC cmdlet requires the GroupPolicy 
   PowerShell Module. The GP cmdlets are avaialbe on machines where the GPMC is installed. 
   The <gponame>.ps1 file will be opened in the PowerShell ISE as a convenience.
.PARAMETER GPOName
    The parameter GPOName is the displayname of the Group Policy Object to be referenced for
    the operation. The 'GPOName' parameter is aliased as 'GPO' for convenience and to conform
    to other GP cmdlets.
.PARAMETER OutputPath
    The 'OutputPath' parameter points to the directory where the DSC document will be created. 
    This parameter is aliased as 'Path' for convenience and to conform to other cmdlets.
.EXAMPLE
   ConvertTo-DSC -GPOName <gpo> -OutputFolder <folder where to create DSC .ps1 file>
.EXAMPLE
   GP2DSC -GPOName <GPO> -OutputFolder <folder>
.LINK
    Http://www.github.com/gpoguy
#>
function ConvertTo-DSC
{
    # add additional cmdletBinding information to make the experience more robust.
    [CmdletBinding()]
    [Alias("GP2DSC")]
    [OutputType([int])]
    # possible new scenarios... optional open in ISE when complete. 
    # optional create of .mof file, including target test machine. This scenario would 
    # be an e2e test where the GPO is selected, Registry data is converted to .ps1 config
    # the configuration is called and .mof is created and DSC configuration is started targeting
    # a test machine.
    Param
    # possibly re-work parameter names.
        ([Parameter(Mandatory=$true)]
        [Alias("GPO")]
        [string]$GPOName,
        
        [Parameter(Mandatory=$true)]
        [Alias("Path")]
        [string] $OutputFolder
        
    )

    Process
    {
        function ADMtoDSC
        {
            param
            ( 
               [String] $gpo,
               [String] $path
            )
            
            $policies = Recurse_PolicyKeys -key "HKLM\Software\Policies" -gpo $gpo
            # ADD SOME OUTPUT IF THERE IS NO SETTINGS IN THIS REGISTRY HIVE CONTINUE SILENTLY AND
            # MENTION IN VERBOSE OUTPUT "No settings in "HKLM\Software\Policies"

            $policies += Recurse_PolicyKeys -key "HKLM\Software\Microsoft\Windows NT\CurrentVersion" -gpo $gpo
            # ADD SOME OUTPUT IF THERE IS NO SETTINGS IN THIS REGISTRY HIVE CONTINUE SILENTLY AND
            # MENTION IN VERBOSE OUTPUT "No settings in "HKLM\Software\Microsoft\Winodws NT\CurrentVersion"

            # build the DSC configuration doc
            GenConfigDoc -path $path -gpo $gpo -policies $policies
            # add error/debug and verbose.
        }

        function Recurse_PolicyKeys
        # This function goes through the registry.pol data and finds entries associated with the 
        # two policy hives mentioned above. Consider rename of the function to be more modular and 
        # powershell'ish
        {
            param
            (
                [string]$key,
                [string]$gpoName
            )
            
            # Get-GPRegistryValue is from the GroupPolicy PowerShell module.
            $current = Get-GPRegistryValue -Name $gpo -Key $key
            foreach ($item in $current)
            {
                if ($item.ValueName -ne $null)
                {
                    [array]$returnVal += $item
                }
                else
                {
                    Recurse_PolicyKeys -Key $item.FullKeyPath -gpoName $gpo
                }
            }
            return $returnVal
            # hmmmmm
        }

        function GenConfigDoc
        # consider rename of function - New-DSCDoc
        # add verbose output, error handling and debugging
        {
            param
            (
                [string] $path,
                [string] $gpo,
                [array] $policies
            )
            #parse the spaces out of the GPO name, since we use it for the Configuration name
            $gpo = $gpo -replace " ","_"
            $outputFile = "$path\$gpo.ps1"
            "Configuration `"$gpo`"" | out-file -FilePath $outputFile
            '{' | out-file -FilePath $outputFile -Append
            'Node localhost' | out-file -FilePath $outputFile -Append
            '  {' | out-file -FilePath $outputFile -Append
            foreach ($regItem in $policies)
            {
                if ($regItem.FullKeyPath -eq $null) #throw away any blank entries
                {
                     continue
                }
                # now build the resources
                # exploring other ways to create the resource info.
                # figure out if certain encoding is needed for the output. ISE shows spaces as
                # unicode character.
                "    Registry `"" + $regItem.ValueName + "`""| out-file -FilePath $outputFile -Append
                '    {' | out-file -FilePath $outputFile -Append
                "      Ensure = `"Present`"" | out-file -FilePath $outputFile -Append
                "      Key = `""+ $regItem.FullKeyPath + "`""| out-file -FilePath $outputFile -Append
                "      ValueName = `"" + $regItem.ValueName + "`"" | out-file -FilePath $outputFile -Append
                "      ValueType = `"" +$regItem.Type + "`"" | out-file -FilePath $outputFile -Append
                "      ValueData = `"" +$regItem.Value + "`""| out-file -FilePath $outputFile -Append
                '    }' | out-file -FilePath $outputFile -Append
            }
            '  }' | out-file -FilePath $outputFile -Append
            '}' | out-file -FilePath $outputFile -Append
            $gpo | out-file -FilePath $outputFile -Append
        }
        ADMToDSC -gpo $gpoName -path $outputFolder
        ISE "$outputfolder\$gponame.ps1"
    }
}