Made Install-Dependencies much faster by only installing missing requirements

build/Install-Dependencies.ps1

@@ -2,26 +2,71 @@
 #  Copyright (c) Microsoft Corporation.  All Rights Reserved.  Licensed under the MIT License.  See License in the project root for license information.
 # ------------------------------------------------------------------------------
 
-[cmdletbinding()]
+[CmdletBinding()]
 param(
-	[ArgumentCompleter({ (Get-ChildItem -Path "$PSScriptRoot\..\module").Name })]
-	[string]
-	$ModuleName = 'Entra',
+    # The name of the module to install dependencies for. The module name should match the folder name in the module folder. If not provided, the script will default to 'Entra'.
+    [ArgumentCompleter({ (Get-ChildItem -Path "$PSScriptRoot\..\module").Name })]
+    [string]
+    $ModuleName = 'Entra',
 
-	[ValidateScript({ Test-Path $_ })]
-	[string]
-    $ModuleSettingsPath
+    # Path to the ModuleSettings.json file. If not provided, the script will look for the file in the module folder.
+    [ValidateScript({ Test-Path $_ })]
+    [string]
+    $ModuleSettingsPath,
+
+    # Force installation of the required modules, even if they are already installed.
+    [switch]
+    $Force
 )
 
-. "$psscriptroot/common-functions.ps1"
+try {
+    # Review: are the common functions required for this script? There does not seem to be any dependencies on them [yet?].
+    . "$PSScriptRoot/common-functions.ps1"
+} catch {
+    Write-Error -Message "Failed to load common-functions.ps1. Error: $_" -RecommendedAction "This script should be run from the 'build' folder. Ensure 'common-functions.ps1' exists and is accessible."
+}
+
+# Get module settings from the relevant ModuleSettings.json file.
+if ($ModuleSettingsPath) {
+    $SettingsPath = $ModuleSettingsPath
+} else {
+    $SettingsPath = "$PSScriptRoot/../module/$ModuleName/config/ModuleSettings.json"
+}
+$ModuleSettings = Get-Content -Path $SettingsPath | ConvertFrom-Json
+$RequiredVersion = $ModuleSettings.destinationModuleVersion
+
+# Do not check for installed modules if -Force is specified.
+if ($Force) {
+    Write-Verbose 'Skipping the check for installed prerequisites. Forcing the installation of all required modules.'
+} else {
+    Write-Verbose 'Checking installed modules for required dependencies.'
+    $InstalledModules = Get-Module -ListAvailable -Verbose:$false | Group-Object -Property Name
+}
 
-$settingPath = "$PSScriptRoot/../module/$ModuleName/config/ModuleSettings.json"
-if ($ModuleSettingsPath) { $settingPath = $ModuleSettingsPath }
-$content = Get-Content -Path $settingPath | ConvertFrom-Json
-Write-Verbose("Installing Module $($content.sourceModule)")
-Install-Module $content.sourceModule -scope currentuser -Force -AllowClobber
+# Install the AzureAD module.
+$SourceModule = $ModuleSettings.sourceModule
+if (($InstalledModules.Name -contains $SourceModule) -and -not $Force) {
+    Write-Verbose "The $SourceModule module is already installed."
+} else {
+    Write-Verbose("Installing Module: $sourceModule")
+    try {
+        Install-Module $sourceModule -Scope CurrentUser -Force -AllowClobber
+    } catch {
+        Write-Error "Failed to install the $sourceModule module. Error: $_"
+    }
+}
 
-foreach ($moduleName in $content.destinationModuleName){
-    Write-Verbose("Installing Module $($moduleName)")
-    Install-Module $moduleName -scope currentuser -RequiredVersion $content.destinationModuleVersion -Force -AllowClobber
-}
+# Install the required module dependencies if missing the required version or if -Force.
+foreach ($moduleName in $ModuleSettings.destinationModuleName) {
+    $InstalledModuleReference = $InstalledModules.Where({ $_.Name -eq $moduleName })
+    if (-not $InstalledModuleReference -or $Force) {
+        Write-Verbose "Installing version $RequiredVersion of $moduleName"
+        try {
+            Install-Module $moduleName -Scope CurrentUser -RequiredVersion $RequiredVersion -Force -AllowClobber
+        } catch {
+            Write-Error "Failed to install module $moduleName ${RequiredVersion}. Error: $_"
+        }
+    } elseif ($InstalledModuleReference.Group.Version -contains $RequiredVersion) {
+        Write-Verbose "Found version $RequiredVersion of $moduleName"
+    }
+}