Improved build cancellation.

Author: gfraiteur

src/PostSharp.Engineering.BuildTools/BaseCommand.cs

@@ -29,7 +29,6 @@ public sealed override int Execute( CommandContext context, T settings )
             CancellationTokenSource? timeoutCancellation = null;
 
             var mainCancellation = new CancellationTokenSource();
-            Console.CancelKeyPress += ( _, _ ) => mainCancellation.Cancel();
 
             try
             {
@@ -50,6 +49,8 @@ public sealed override int Execute( CommandContext context, T settings )
                     buildContext = buildContext.WithUseProjectDirectoryAsWorkingDirectory( true );
                 }
 
+                Console.CancelKeyPress += ( _, _ ) => OnCancel( buildContext, mainCancellation );
+
                 // Sets up a timeout. The Timer class does not support long periods, so we use CancellationTokenSource.
                 if ( settings.Timeout != null )
                 {
@@ -156,6 +157,8 @@ public sealed override int Execute( CommandContext context, T settings )
 
                 if ( buildContext.CancellationToken.IsCancellationRequested )
                 {
+                    buildContext.Console.WriteError( "The build was cancelled." );
+
                     return (int) ExitCode.Cancelled;
                 }
 
@@ -180,6 +183,34 @@ public sealed override int Execute( CommandContext context, T settings )
 
         protected abstract bool ExecuteCore( BuildContext context, T settings );
 
+        private static void OnCancel( BuildContext buildContext, CancellationTokenSource mainCancellation )
+        {
+            var console = buildContext.Console;
+
+            if ( RuntimeInformation.IsOSPlatform( OSPlatform.Windows ) )
+            {
+                console.WriteError( $"Cancelling and killing all child processes." );
+
+                // List all child processes.
+                var processes = ProcessHelper.GetProcessTree( console, Process.GetCurrentProcess().Id );
+
+                console.WriteMessage( "Process tree:" );
+
+                foreach ( var node in processes )
+                {
+                    var indent = new string( '-', (node.NestingLevel + 1) * 3 );
+                    console.WriteMessage( $"+{indent} {node.Process.Id} {ProcessHelper.GetCommandLine( node.Process )}" );
+                }
+
+                // Kill all processes (except the current one) in reverse order.
+                ProcessHelper.KillProcesses( console, processes.Reverse().Select( x => x.Process ) );
+            }
+
+            // Signal the main cancellation source.
+            // We don't exit the process so exception handlers and finally blocks can run.
+            mainCancellation.Cancel();
+        }
+
         private static void OnTimeout( BuildContext buildContext, Stopwatch stopwatch, CancellationTokenSource mainCancellation )
         {
             var console = buildContext.Console;
@@ -212,8 +243,13 @@ private static void OnTimeout( BuildContext buildContext, Stopwatch stopwatch, C
             else
             {
                 console.WriteError( $"The process timed out after {stopwatch.Elapsed}. Exiting." );
+                mainCancellation.Cancel();
             }
 
+            // Give the normal cancellation workflow a chance to complete.
+            Thread.Sleep( 10 );
+
+            // If we're still here, we're abruptly terminating the process.
             console.WriteWarning( "Terminating the current process." );
             Environment.FailFast( $"The process timed out after {stopwatch.Elapsed}." );
         }

src/PostSharp.Engineering.BuildTools/Resources/DockerBuild.ps1

@@ -90,6 +90,12 @@ function New-EnvJson
     return $jsonPath
 }
 
+if ($env:RUNNING_IN_DOCKER)
+{
+    Write-Error "Already running in Docker."
+    exit 1
+}
+
 # Generate ImageName from script directory if not provided
 if ( [string]::IsNullOrEmpty($ImageName))
 {
@@ -103,7 +109,8 @@ if ( [string]::IsNullOrEmpty($ImageName))
         $ImageTag = "docker-build-image"
     }
     Write-Host "Generated image name from directory: $ImageTag" -ForegroundColor Cyan
-} else
+}
+else
 {
     # Generate a hash of the repo directory tagging (4 bytes, 8 hex chars)
     $hashBytes = (New-Object -TypeName System.Security.Cryptography.SHA256Managed).ComputeHash([System.Text.Encoding]::UTF8.GetBytes($PSScriptRoot))
@@ -264,7 +271,7 @@ Write-Host "Git directories: " $gitDirectoriesAsString -ForegroundColor Gray
 # Kill all containers
 docker ps -q --filter "ancestor=$ImageTag" | ForEach-Object {
     Write-Host "Killing container $_"
-    docker kill $_ 
+    docker kill $_
 }
 
 # Building the image.

src/PostSharp.Engineering.BuildTools/Utilities/ConsoleHelper.cs

@@ -14,13 +14,6 @@ public class ConsoleHelper
     {
         private static readonly CancellationTokenSource _cancellationTokenSource = new();
 
-        static ConsoleHelper()
-        {
-            Console.CancelKeyPress += OnCancel;
-        }
-
-        private static void OnCancel( object? sender, ConsoleCancelEventArgs e ) => _cancellationTokenSource.Cancel();
-
         public static void Cancel() => _cancellationTokenSource.Cancel();
 
         // This now de facto a synonym of BuildContext.CancellationToken, but unifying this requires many changes.