Add Python tools installation from Github releases for Windows (#705)

* Add Toolset provision for Windows
Co-authored-by: MaksimZhukov <v-mazhuk@microsoft.com>

images/win/scripts/Installers/Install-Toolset.ps1

@@ -0,0 +1,76 @@
+################################################################################
+##  File:  Install-Toolset.ps1
+##  Team:  CI-Build
+##  Desc:  Install toolset
+################################################################################
+
+Function Install-Asset {
+    param(
+        [Parameter(Mandatory=$true)]
+        [object] $ReleaseAsset
+    )
+
+    $releaseAssetName = [System.IO.Path]::GetFileNameWithoutExtension($ReleaseAsset.filename)
+    $assetFolderPath = Join-Path $env:TEMP $releaseAssetName
+    $assetArchivePath = Start-DownloadWithRetry -Url $ReleaseAsset.download_url -Name $ReleaseAsset.filename
+
+    Write-Host "Extract $($ReleaseAsset.filename) content..."
+    7z.exe x $assetArchivePath -o"$assetFolderPath" -y | Out-Null
+
+    Write-Host "Invoke installation script..."
+    Push-Location -Path $assetFolderPath
+    Invoke-Expression .\setup.ps1
+    Pop-Location
+}
+
+Function Set-DefaultPythonVersion {
+    param(
+        [Parameter(Mandatory=$true)]
+        [object[]] $Toolset
+    )
+
+    $python = $Toolset  | Where-Object { ($_.name -eq "Python") -and ($_.default -ne "") } `
+                        | Select-Object default, arch -First 1
+
+    if ($python.default -ne $null) {
+        $pythonPath = Join-Path $Env:AGENT_TOOLSDIRECTORY "/Python/$($python.default)/$($python.arch)" -Resolve
+
+        Write-Host "Use Python $($python.default) as a system Python"
+        Add-MachinePathItem -PathItem $pythonPath
+        Add-MachinePathItem -PathItem "$pythonPath\Scripts"
+    } else {
+        Write-Host "Default Python version not found in toolset file!"
+    }
+}
+
+$ErrorActionPreference = "Stop"
+
+Import-Module -Name ImageHelpers -Force
+
+# Get toolcache content from toolset
+$tools = Get-ToolsetContent | Select-Object -ExpandProperty toolcache
+
+foreach ($tool in $tools) {
+    # Get versions manifest for current tool
+    $assets = Invoke-RestMethod $tool.url
+
+    # Get github release asset for each version
+    foreach ($toolVersion in $tool.versions) {
+        $asset = $assets | Where-Object version -like $toolVersion `
+                         | Sort-Object -Property {[version]$_.version} -Descending `
+                         | Select-Object -ExpandProperty files `
+                         | Where-Object { ($_.platform -eq $tool.platform) -and ($_.arch -eq $tool.arch) } `
+                         | Select-Object -First 1
+
+        Write-Host "Installing $($tool.name) $toolVersion $($tool.arch)..."
+        if ($asset -ne $null) {
+            Install-Asset -ReleaseAsset $asset
+        } else {
+            Write-Host "Asset was not found in versions manifest"
+            exit 1
+        }
+    }
+}
+
+# Install default python version
+Set-DefaultPythonVersion -Toolset $tools