A set of tools that might be useful later (#7180)

tools/bootstrap/python_.ps1

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+# bootstrap/python_.ps1
+#
+# Python bootstrapping script for Windows.
+#
+# Automatically downloads a portable edition of a pinned Python version to
+# a cache directory, installs Pip, installs `requirements.txt`, and then invokes
+# Python.
+#
+# The underscore in the name is so that typing `bootstrap/python` into
+# PowerShell finds the `.bat` file first, which ensures this script executes
+# regardless of ExecutionPolicy.
+$host.ui.RawUI.WindowTitle = "starting :: python $args"
+$ErrorActionPreference = "Stop"
+[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12
+Add-Type -AssemblyName System.IO.Compression.FileSystem
+
+function ExtractVersion {
+	param([string] $Path, [string] $Key)
+	foreach ($Line in Get-Content $Path) {
+		if ($Line.StartsWith("export $Key=")) {
+			return $Line.Substring("export $Key=".Length)
+		}
+	}
+	throw "Couldn't find value for $Key in $Path"
+}
+
+# Convenience variables
+$Bootstrap = Split-Path $script:MyInvocation.MyCommand.Path
+$Tools = Split-Path $Bootstrap
+$Cache = "$Bootstrap/.cache"
+if ($Env:TG_BOOTSTRAP_CACHE) {
+	$Cache = $Env:TG_BOOTSTRAP_CACHE
+}
+$PythonVersion = ExtractVersion -Path "$Bootstrap/../../_build_dependencies.sh" -Key "PYTHON_VERSION"
+$PythonDir = "$Cache/python-$PythonVersion"
+$PythonExe = "$PythonDir/python.exe"
+$Log = "$Cache/last-command.log"
+
+# Download and unzip a portable version of Python
+if (!(Test-Path $PythonExe -PathType Leaf)) {
+	$host.ui.RawUI.WindowTitle = "Downloading Python $PythonVersion..."
+	New-Item $Cache -ItemType Directory -ErrorAction silentlyContinue | Out-Null
+
+	$Archive = "$Cache/python-$PythonVersion-embed.zip"
+	Invoke-WebRequest `
+		"https://www.python.org/ftp/python/$PythonVersion/python-$PythonVersion-embed-amd64.zip" `
+		-OutFile $Archive `
+		-ErrorAction Stop
+
+	[System.IO.Compression.ZipFile]::ExtractToDirectory($Archive, $PythonDir)
+
+	$PythonVersionArray = $PythonVersion.Split(".")
+	$PythonVersionString = "python$($PythonVersionArray[0])$($PythonVersionArray[1])"
+	Write-Output "Generating PATH descriptor."
+	New-Item "$Cache/$PythonVersionString._pth" | Out-Null
+	Set-Content "$Cache/$PythonVersionString._pth" "$PythonVersionString.zip`n.`n..\..\..`nimport site`n"
+	# Copy a ._pth file without "import site" commented, so pip will work
+	Copy-Item "$Cache/$PythonVersionString._pth" $PythonDir `
+		-ErrorAction Stop
+
+	Remove-Item $Archive
+}
+
+# Install pip
+if (!(Test-Path "$PythonDir/Scripts/pip.exe")) {
+	$host.ui.RawUI.WindowTitle = "Downloading Pip..."
+
+	Invoke-WebRequest "https://bootstrap.pypa.io/get-pip.py" `
+		-OutFile "$Cache/get-pip.py" `
+		-ErrorAction Stop
+
+	& $PythonExe "$Cache/get-pip.py" --no-warn-script-location
+	if ($LASTEXITCODE -ne 0) {
+		exit $LASTEXITCODE
+	}
+
+	Remove-Item "$Cache/get-pip.py" `
+		-ErrorAction Stop
+}
+
+# Use pip to install our requirements
+if (!(Test-Path "$PythonDir/requirements.txt") -or ((Get-FileHash "$Tools/requirements.txt").hash -ne (Get-FileHash "$PythonDir/requirements.txt").hash)) {
+	$host.ui.RawUI.WindowTitle = "Updating dependencies..."
+
+	& $PythonExe -m pip install -U pip -r "$Tools/requirements.txt"
+	if ($LASTEXITCODE -ne 0) {
+		exit $LASTEXITCODE
+	}
+
+	Copy-Item "$Tools/requirements.txt" "$PythonDir/requirements.txt"
+	Write-Output "`n---`n"
+}
+
+# Invoke python with all command-line arguments
+Write-Output $PythonExe | Out-File -Encoding utf8 $Log
+[System.String]::Join([System.Environment]::NewLine, $args) | Out-File -Encoding utf8 -Append $Log
+Write-Output "---" | Out-File -Encoding utf8 -Append $Log
+$host.ui.RawUI.WindowTitle = "python $args"
+$ErrorActionPreference = "Continue"
+& $PythonExe -u $args 2>&1 | ForEach-Object {
+	$str = "$_"
+	if ($_.GetType() -eq [System.Management.Automation.ErrorRecord]) {
+		$str = $str.TrimEnd("`r`n")
+	}
+	$str | Out-File -Encoding utf8 -Append $Log
+	$str | Out-Host
+}
+exit $LastExitCode