cFg

0.3

Initialize-DSCResource.ps1

function Initialize-DSCResource
{
    <#
    .Synopsis
        Initializes DSC resources within a module
    .Description
        Initializes DSC resources within a module, based off of scripts named *.version.resource.ps1 (i.e. foo.1.0.resource.ps1)
    .Link
        Reset-DSCResource
    .Example
        Initialize-DSCResource $env:ProgramFiles\WindowsPowerShell\Modules\cFg
    .Notes
        The .resource.ps1 files are used as a quick way to write a DSC resource.
         
        They are expected to contain a call to Write-DSCResource, and that call will use some default parameters based off of what was provided to Initialize-DSCResource. -ModuleRoot will be the base path of the module, and -ResourceName and -ResourceVersion will be inferred from the file.
    #>    
    [OutputType([Nullable])]
    param(
    # The root directory of the module.
    [Parameter(Mandatory=$true,Position=0,ValueFromPipelineByPropertyName=$true)]
    [Alias('Path')]
    [string]
    $ModuleRoot,
    
    # If set, will always recreate resources, even if they are the same version
    [Switch]
    $Force,

    # If provided, will not initialize resources whose version number is less then the provided value
    [Version]
    $MinimumVersion,

    # If provided, will not initialize resources whose version number is greater then the provided value
    [Version]
    $MaximumVersion
    )

    process {        
        if ($_ -is [Management.Automation.PSModuleInfo]) {
            $ModuleRoot = $ModuleRoot | Split-Path
        }

        $resourcePs1Files = Get-ChildItem -Recurse -Filter *resource*.ps1 -Path $ModuleRoot
        
        $oldDefault = $null
        $oldDefault = $PSDefaultParameterValues["Write-DSCResource:ModuleRoot"]

        $PSDefaultParameterValues["Write-DSCResource:ModuleRoot"] = $ModuleRoot
        #region Locate any resource.ps1 files
        $ResourceData = 
            foreach ($rp in $resourcePs1Files) {
                if ($rp.Name -like "*-*") {
                    Write-Verbose "Skipping Potential Resource File $rp, because it looks like a function"
                    continue
                }
                $nameParts = $rp.Name.Split('.')

                $v = $nameParts[-6..-3] -join '.' -as [Version]
                $resourceName = $nameParts[0..($nameParts.Count - 7)] -join '.'
                if (-not $v) {
                    $v = $nameParts[-5..-3] -join '.' -as [Version]
                    $resourceName = $nameParts[0..($nameParts.Count - 6)] -join '.'
                }
                if (-not $v) {
                    $v = $nameParts[-4..-3] -join '.' -as [Version]
                    $resourceName = $nameParts[0..($nameParts.Count - 5)] -join '.'
                }
                if (-not $v) {
                    $v = '0.0' -as [Version]
                    $resourceName = $nameParts[0..($nameParts.Count - 2)] -join '.'
                }
            
            

                New-Object PSObject -Property @{
                    ResourceName = $resourceName
                    ResourcePath = $rp.Fullname
                    ResourceVersion = $v 
                }
            }
        #endregion Locate any resource.ps1 files

        #region Run each resource file
        foreach ($rd in $ResourceData) {
            if ($MinimumVersion -and $rd.ResourceVersion -lt $MinimumVersion) {
                continue
            }
            if ($maximumVersion -and $rd.ResourceVersion -gt $maximumVersion) {
                continue
            }
            
            
            $existingResourceFiles = Get-ChildItem -Path (Join-Path $moduleRoot DSCResources) -Filter $rd.ResourceName  -ErrorAction SilentlyContinue |
                Get-ChildItem


            $shouldCreate = $true
            if ($existingResourceFiles) {
                $existingMof = $existingResourceFiles | ? {$_.Extension -eq '.mof' } 
                if ($existingMof) {
                    $versionLine = [IO.File]::ReadAllLines($existingMof.FullName) | 
                        Where-Object {$_ -like "*ClassVersion*" } | 
                        Select-Object -First 1 

                    $versionParts = $versionLine -split "[\[\],]" -ne ''
                    $versionPart = $versionParts |? { $_ -like "*ClassVersion*" } 
                    $ExistingVersion = ($versionPart -split '"')[1] -as [Version]

                    if ($ExistingVersion -lt $rd.ResourceVersion) {
                        $shouldCreate = $true
                    } else {
                        $shouldCreate = $false
                    }
                }


            }

            if ((-not $shouldCreate) -and -not $Force) {
                Write-Verbose "Skipping $($rd.ResourceName) v$($rd.ResourceVersion) because the same or a newer version exists"
                continue
            }

            

            $oldDefaultVersion = $PSDefaultParameterValues["Write-DSCResource:Version"]
            $oldDefaultResourceName = $PSDefaultParameterValues["Write-DSCResource:ResourceName"]
            $PSDefaultParameterValues["Write-DSCResource:ResourceName"] = $rd.resourceName
            $PSDefaultParameterValues["Write-DSCResource:Version"] = $rd.ResourceVersion

            & $rd.ResourcePath

            if ($oldDefaultVersion) {
                $PSDefaultParameterValues["Write-DSCResource:Version"] = $oldDefaultVersion
            } else {
                $PSDefaultParameterValues.Remove("Write-DSCResource:Version")
            }

            if ($oldDefaultResourceName) {
                $PSDefaultParameterValues["Write-DSCResource:ResourceName"] = $oldDefaultResourceName
            } else {
                $PSDefaultParameterValues.Remove("Write-DSCResource:ResourceName")
            }
        }
        
        #region Run each resource file


        if ($oldDefault) {
            $PSDefaultParameterValues["Write-DSCResource:ModuleRoot"] = $oldDefault
        } else {
            $PSDefaultParameterValues.Remove("Write-DSCResource:ModuleRoot")
        }
        
    }
}