1 files changed, 53 insertions, 2 deletions

diff --git a/eng/common/tools.ps1 b/eng/common/tools.ps1
index 4b2552032..5d526c74d 100644
--- a/eng/common/tools.ps1
+++ b/eng/common/tools.ps1
@@ -42,7 +42,7 @@
 [bool]$useInstalledDotNetCli = if (Test-Path variable:useInstalledDotNetCli) { $useInstalledDotNetCli } else { $true }
 
 # Enable repos to use a particular version of the on-line dotnet-install scripts.
-#    default URL: https://dot.net/v1/dotnet-install.ps1
+#    default URL: https://dotnet.microsoft.com/download/dotnet/scripts/v1/dotnet-install.ps1
 [string]$dotnetInstallScriptVersion = if (Test-Path variable:dotnetInstallScriptVersion) { $dotnetInstallScriptVersion } else { 'v1' }
 
 # True to use global NuGet cache instead of restoring packages to repository-local directory.
@@ -106,6 +106,46 @@ function Exec-Process([string]$command, [string]$commandArgs) {
   }
 }
 
+# Take the given block, print it, print what the block probably references from the current set of
+# variables using low-effort string matching, then run the block.
+#
+# This is intended to replace the pattern of manually copy-pasting a command, wrapping it in quotes,
+# and printing it using "Write-Host". The copy-paste method is more readable in build logs, but less
+# maintainable and less reliable. It is easy to make a mistake and modify the command without
+# properly updating the "Write-Host" line, resulting in misleading build logs. The probability of
+# this mistake makes the pattern hard to trust when it shows up in build logs. Finding the bug in
+# existing source code can also be difficult, because the strings are not aligned to each other and
+# the line may be 300+ columns long.
+#
+# By removing the need to maintain two copies of the command, Exec-BlockVerbosely avoids the issues.
+#
+# In Bash (or any posix-like shell), "set -x" prints usable verbose output automatically.
+# "Set-PSDebug" appears to be similar at first glance, but unfortunately, it isn't very useful: it
+# doesn't print any info about the variables being used by the command, which is normally the
+# interesting part to diagnose.
+function Exec-BlockVerbosely([scriptblock] $block) {
+  Write-Host "--- Running script block:"
+  $blockString = $block.ToString().Trim()
+  Write-Host $blockString
+
+  Write-Host "--- List of variables that might be used:"
+  # For each variable x in the environment, check the block for a reference to x via simple "$x" or
+  # "@x" syntax. This doesn't detect other ways to reference variables ("${x}" nor "$variable:x",
+  # among others). It only catches what this function was originally written for: simple
+  # command-line commands.
+  $variableTable = Get-Variable |
+    Where-Object {
+      $blockString.Contains("`$$($_.Name)") -or $blockString.Contains("@$($_.Name)")
+    } |
+    Format-Table -AutoSize -HideTableHeaders -Wrap |
+    Out-String
+  Write-Host $variableTable.Trim()
+
+  Write-Host "--- Executing:"
+  & $block
+  Write-Host "--- Done running script block!"
+}
+
 # createSdkLocationFile parameter enables a file being generated under the toolset directory
 # which writes the sdk's location into. This is only necessary for cmd --> powershell invocations
 # as dot sourcing isn't possible.
@@ -223,7 +263,7 @@ function GetDotNetInstallScript([string] $dotnetRoot) {
   if (!(Test-Path $installScript)) {
     Create-Directory $dotnetRoot
     $ProgressPreference = 'SilentlyContinue' # Don't display the console progress UI - it's a huge perf hit
-    $uri = "https://dot.net/$dotnetInstallScriptVersion/dotnet-install.ps1"
+    $uri = "https://dotnet.microsoft.com/download/dotnet/scripts/$dotnetInstallScriptVersion/dotnet-install.ps1"
 
     Retry({
       Write-Host "GET $uri"
@@ -632,6 +672,17 @@ function ExitWithExitCode([int] $exitCode) {
   exit $exitCode
 }
 
+# Check if $LASTEXITCODE is a nonzero exit code (NZEC). If so, print a Azure Pipeline error for
+# diagnostics, then exit the script with the $LASTEXITCODE.
+function Exit-IfNZEC([string] $category = "General") {
+  Write-Host "Exit code $LASTEXITCODE"
+  if ($LASTEXITCODE -ne 0) {
+    $message = "Last command failed with exit code $LASTEXITCODE."
+    Write-PipelineTelemetryError -Force -Category $category -Message $message
+    ExitWithExitCode $LASTEXITCODE
+  }
+}
+
 function Stop-Processes() {
   Write-Host 'Killing running build processes...'
   foreach ($processName in $processesToStopOnExit) {