Refactor PackageProps to make the Yaml loading and processing methods…

… common (#9236)

* Refactor PackageProps to make the Yaml loading and processing methods common

* Updates for feedback

eng/common/scripts/Helpers/Package-Helpers.ps1

@@ -90,4 +90,90 @@ function CompatibleConvertFrom-Yaml {
   else {
       return ConvertFrom-Yaml $content
   }
+}
+
+<#
+.SYNOPSIS
+Common function that will verify that the YmlFile being loaded exists, load the raw file and
+return the results of CompatibleConvertFrom-Yaml or report an exception and return null if
+there's a problem loading the yml file. The return is the PowerShell HashTable object.
+
+.DESCRIPTION
+Common function that will verify that the YmlFile being loaded exists, load the raw file and
+return the results of CompatibleConvertFrom-Yaml or report an exception and return null if
+there's a problem loading the yml file. This is just to save anyone needing to load yml from
+having to deal with checking the file's existence and ensure that the CompatibleConvertFrom-Yaml
+is made within a try/catch. The return is the PowerShell HashTable object from the
+CompatibleConvertFrom-Yaml call or $null if there was an issue with the convert.
+
+.PARAMETER YmlFile
+The full path of the yml file to load.
+
+.EXAMPLE
+LoadFrom-Yaml -YmlFile path/to/file.yml
+#>
+function LoadFrom-Yaml {
+  param(
+    [Parameter(Mandatory=$true)]
+    [string]$YmlFile
+  )
+  if (Test-Path -Path $YmlFile) {
+    try {
+      return Get-Content -Raw -Path $YmlFile | CompatibleConvertFrom-Yaml
+    }
+    catch {
+      Write-Host "LoadFrom-Yaml::Exception while parsing yml file $($YmlFile): $_"
+    }
+  }
+  else {
+    Write-Host "LoadFrom-Yaml::YmlFile '$YmlFile' does not exist."
+  }
+  return $null
+}
+
+<#
+.SYNOPSIS
+Given the Hashtable contents of a Yml file and an array of strings representing the keys
+return the value if it exist or null if it doesn't.
+
+.DESCRIPTION
+The Yaml file needs to be loaded via CompatibleConvertFrom-Yaml which returns the file as
+as hashtable. The Keys are basically the path in the yaml file whose value to return, or
+null if it doesn't exist. This function safely traverses the path, outputting an error
+if there's an issue or returning the object representing the result if successful. This
+function loops through the Keys safely trying to get values, checking each piece of the
+path to ensure it exists. Normally one would just do
+$Yml["extends"]["parameters"]["artifacts"]
+but if something was off it would throw. Doing it this way allows more succinct error
+reporting if a piece of the path didn't exist
+
+.PARAMETER YamlContentAsHashtable
+The hashtable representing the yaml file contents loaded through LoadFrom-Yaml
+or CompatibleConvertFrom-Yaml, which is what LoadFrom-Yaml calls.
+
+.PARAMETER Keys
+String array representation of the path in the yaml file whose value we're trying to retrieve.
+
+.EXAMPLE
+GetValueSafelyFrom-Yaml -YamlContentAsHashtable $YmlFileContent -Keys @("extends", "parameters", "Artifacts")
+#>
+function GetValueSafelyFrom-Yaml {
+  param(
+    [Parameter(Mandatory=$true)]
+    $YamlContentAsHashtable,
+    [Parameter(Mandatory=$true)]
+    [string[]]$Keys
+  )
+  $current = $YamlContentAsHashtable
+  foreach ($key in $Keys) {
+      if ($current.ContainsKey($key) -or $current[$key]) {
+        $current = $current[$key]
+      }
+      else {
+        Write-Host "The '$key' part of the path $($Keys -join "/") doesn't exist or is null."
+        return $null
+      }
+  }
+
+  return [object]$current
 }

eng/common/scripts/Package-Properties.ps1

@@ -17,7 +17,8 @@ class PackageProps
     [string]$ReleaseStatus
     # was this package purely included because other packages included it as an AdditionalValidationPackage?
     [boolean]$IncludedForValidation
-    # does this package include other packages that we should trigger validation for?
+    # does this package include other packages that we should trigger validation for or
+    # additional packages required for validation of this one
     [string[]]$AdditionalValidationPackages
     [HashTable]$ArtifactDetails
 
@@ -83,42 +84,21 @@ class PackageProps
         $this.Group = $group
     }
 
-    hidden [object]GetValueSafely($hashtable, [string[]]$keys) {
-        $current = $hashtable
-        foreach ($key in $keys) {
-            if ($current.ContainsKey($key) -or $current[$key]) {
-                $current = $current[$key]
-            }
-            else {
-                return $null
-            }
-        }
+    hidden [HashTable]ParseYmlForArtifact([string]$ymlPath) {
 
-        return $current
-    }
+        $content = LoadFrom-Yaml $ymlPath
+        if ($content) {
+            $artifacts = GetValueSafelyFrom-Yaml $content @("extends", "parameters", "Artifacts")
+            $artifactForCurrentPackage = $null
 
-    hidden [HashTable]ParseYmlForArtifact([string]$ymlPath) {
-        if (Test-Path -Path $ymlPath) {
-            try {
-                $content = Get-Content -Raw -Path $ymlPath | CompatibleConvertFrom-Yaml
-                if ($content) {
-                    $artifacts = $this.GetValueSafely($content, @("extends", "parameters", "Artifacts"))
-                    $artifactForCurrentPackage = $null
-
-                    if ($artifacts) {
-                        $artifactForCurrentPackage = $artifacts | Where-Object { $_["name"] -eq $this.ArtifactName -or $_["name"] -eq $this.Name }
-                    }
-
-                    if ($artifactForCurrentPackage) {
-                        return [HashTable]$artifactForCurrentPackage
-                    }
-                }
+            if ($artifacts) {
+                $artifactForCurrentPackage = $artifacts | Where-Object { $_["name"] -eq $this.ArtifactName -or $_["name"] -eq $this.Name }
             }
-            catch {
-              Write-Host "Exception while parsing yml file $($ymlPath): $_"
+
+            if ($artifactForCurrentPackage) {
+                return [HashTable]$artifactForCurrentPackage
             }
         }
-
         return $null
     }