Add FilteredExport resource and update export method handling

Author: Gijsreyn

adapters/powershell/Tests/TestClassResource/0.0.1/TestClassResource.psd1

@@ -34,7 +34,7 @@ VariablesToExport = @()
 AliasesToExport = @()
 
 # DSC resources to export from this module
-DscResourcesToExport = @('TestClassResource', 'NoExport')
+DscResourcesToExport = @('TestClassResource', 'NoExport', 'FilteredExport')
 
 # Private data to pass to the module specified in RootModule/ModuleToProcess. This may also contain a PSData hashtable with additional module metadata used by PowerShell.
 PrivateData = @{

adapters/powershell/Tests/TestClassResource/0.0.1/TestClassResource.psm1

@@ -155,6 +155,52 @@ class NoExport: BaseTestClass
     }
 }
 
+[DscResource()]
+class FilteredExport : BaseTestClass
+{
+    [DscProperty(Key)]
+    [string] $Name
+
+    [DscProperty()]
+    [string] $Prop1
+
+    [void] Set()
+    {
+    }
+
+    [bool] Test()
+    {
+        return $true
+    }
+
+    [FilteredExport] Get()
+    {
+        return $this
+    }
+
+    static [FilteredExport[]] Export()
+    {
+        $resultList = [List[FilteredExport]]::new()
+        $obj = New-Object FilteredExport
+        $obj.Name = "DefaultObject"
+        $obj.Prop1 = "Default Property"
+        $resultList.Add($obj)
+
+        return $resultList.ToArray()
+    }
+
+    static [FilteredExport[]] Export([FilteredExport]$Name)
+    {
+        $resultList = [List[FilteredExport]]::new()
+        $obj = New-Object FilteredExport
+        $obj.Name = $Name
+        $obj.Prop1 = "Filtered Property for $Name"
+        $resultList.Add($obj)
+
+        return $resultList.ToArray()
+    }
+}
+
 function Test-World()
 {
     "Hello world from PSTestModule!"

adapters/powershell/Tests/powershellgroup.config.tests.ps1

@@ -105,6 +105,49 @@ Describe 'PowerShell adapter resource tests' {
     $out | Should -BeLike "*ERROR*Export method not implemented by resource 'TestClassResource/NoExport'*"
   }
 
+  It 'Export works with filtered export property' {
+    $yaml = @'
+            $schema: https://aka.ms/dsc/schemas/v3/bundled/config/document.json
+            resources:
+            - name: Working with class-based resources
+              type: Microsoft.DSC/PowerShell
+              properties:
+                resources:
+                - name: Class-resource Info
+                  type: TestClassResource/FilteredExport
+                  properties:
+                    Name: 'FilteredExport'
+'@
+    $out = $yaml | dsc -l trace config export -f - 2> "$TestDrive/export_trace.txt"
+    $LASTEXITCODE | Should -Be 0
+    $res = $out | ConvertFrom-Json
+    $res.'$schema' | Should -BeExactly 'https://aka.ms/dsc/schemas/v3/bundled/config/document.json'
+    $res.'resources' | Should -Not -BeNullOrEmpty
+    $res.resources[0].properties.result.count | Should -Be 1
+    $res.resources[0].properties.result[0].Name | Should -Be "FilteredExport"
+    $res.resources[0].properties.result[0].Prop1 | Should -Be "Filtered Property for FilteredExport"
+    "$TestDrive/export_trace.txt" | Should -FileContentMatch "Properties provided for filtered export"
+  }
+
+  It 'Export fails when filtered export is requested but not implemented' {
+    $yaml = @'
+            $schema: https://aka.ms/dsc/schemas/v3/bundled/config/document.json
+            resources:
+            - name: Working with class-based resources
+              type: Microsoft.DSC/PowerShell
+              properties:
+                resources:
+                - name: Class-resource Info
+                  type: TestClassResource/NoExport
+                  properties:
+                    Name: 'SomeFilter'
+'@
+    $out = $yaml | dsc config export -f - 2>&1 | Out-String
+    $LASTEXITCODE | Should -Be 2
+    $out | Should -Not -BeNullOrEmpty
+    $out | Should -BeLike "*ERROR*Export method with parameters not implemented by resource 'TestClassResource/NoExport'*"
+  }
+
   It 'Custom psmodulepath in config works' {
 
     $OldPSModulePath = $env:PSModulePath

adapters/powershell/psDscAdapter/powershell.resource.ps1

@@ -181,7 +181,7 @@ switch ($Operation) {
             # process the INPUT (desiredState) for each resource as dscresourceInfo and return the OUTPUT as actualState
             $actualState = $psDscAdapter.invoke( { param($op, $ds, $dscResourceCache) Invoke-DscOperation -Operation $op -DesiredState $ds -dscResourceCache $dscResourceCache }, $Operation, $ds, $dscResourceCache)
             if ($null -eq $actualState) {
-                Write-DscTrace -Operation Error -Message 'Incomplete GET for resource ' + $ds.Name
+                "Failed to invoke operation '{0}' for resource name '{1}'." -f $Operation, $ds.Name | Write-DscTrace -Operation Error
                 exit 1
             }
             if ($null -ne $actualState.Properties -and $actualState.Properties.InDesiredState -eq $false) {

adapters/powershell/psDscAdapter/psDscAdapter.psm1

@@ -150,6 +150,42 @@ function FindAndParseResourceDefinitions {
     return $resourceList
 }
 
+function GetExportMethod ($ResourceType, $HasFilterProperties, $ResourceTypeName) {
+    $methods = $ResourceType.GetMethods() | Where-Object { $_.Name -eq 'Export' }
+    $method = $null
+    
+    if ($HasFilterProperties) {
+        "Properties provided for filtered export" | Write-DscTrace -Operation Trace
+        $method = foreach ($mt in $methods) {
+            if ($mt.GetParameters().Count -gt 0) {
+                $mt
+                break
+            }
+        }
+        
+        if ($null -eq $method) {
+            "Export method with parameters not implemented by resource '$ResourceTypeName'. Filtered export is not supported." | Write-DscTrace -Operation Error
+            exit 1
+        }
+    }
+    else {
+        "No properties provided, using parameterless export" | Write-DscTrace -Operation Trace
+        $method = foreach ($mt in $methods) {
+            if ($mt.GetParameters().Count -eq 0) {
+                $mt
+                break
+            }
+        }
+        
+        if ($null -eq $method) {
+            "Export method not implemented by resource '$ResourceTypeName'" | Write-DscTrace -Operation Error
+            exit 1
+        }
+    }
+    
+    return $method
+}
+
 function LoadPowerShellClassResourcesFromModule {
     [CmdletBinding(HelpUri = '')]
     param(
@@ -471,20 +507,18 @@ function Invoke-DscOperation {
                         }
                         'Export' {
                             $t = $dscResourceInstance.GetType()
-                            $methods = $t.GetMethods() | Where-Object { $_.Name -eq 'Export' }
-                            $method = foreach ($mt in $methods) {
-                                if ($mt.GetParameters().Count -eq 0) {
-                                    $mt
-                                    break
-                                }
-                            }
+                            $hasFilter = $null -ne $DesiredState.properties -and 
+                            ($DesiredState.properties.PSObject.Properties | Measure-Object).Count -gt 0
+
+                            $method = GetExportMethod -ResourceType $t -HasFilterProperties $hasFilter -ResourceTypeName $DesiredState.Type
 
-                            if ($null -eq $method) {
-                                "Export method not implemented by resource '$($DesiredState.Type)'" | Write-DscTrace -Operation Error
-                                exit 1
-                            }
                             $resultArray = @()
-                            $raw_obj_array = $method.Invoke($null, $null)
+                            if ($hasFilter) {
+                                $raw_obj_array = $method.Invoke($null, @($dscResourceInstance))
+                            } else {
+                                $raw_obj_array = $method.Invoke($null, $null)
+                            }
+
                             foreach ($raw_obj in $raw_obj_array) {
                                 $Result_obj = @{}
                                 $ValidProperties | ForEach-Object {