Improve failure reporting when platform tools fail to start

src/Particular.PlatformSample/PlatformLauncher.cs

@@ -97,8 +97,15 @@ public static async Task Launch(bool showPlatformToolConsoleOutput = false, stri
             launcher.ServicePulse(pulsePort, controlPort, monitoringPort, servicePulseDefaultRoute);
 
             Console.Write("Waiting for ServiceControl to be available");
-            await Network.WaitForHttpOk($"http://localhost:{controlPort}/api", stopWaiting: () => launcher.FindExitedTools().Count > 0, cancellationToken: tokenSource.Token)
-                .ConfigureAwait(false);
+            try
+            {
+                await Network.WaitForHttpOk($"http://localhost:{controlPort}/api", stopWaiting: () => launcher.FindExitedTools().Count > 0, cancellationToken: tokenSource.Token)
+                    .ConfigureAwait(false);
+            }
+            catch (OperationCanceledException) when (tokenSource.Token.IsCancellationRequested)
+            {
+                // Ctrl+C was pressed, or the caller cancelled, before ServiceControl was available
+            }
 
             // A platform tool exited on its own (not because of Ctrl+C), for example because the .NET runtime version it requires is not installed
             var failedTools = launcher.FindExitedTools();
@@ -108,11 +115,19 @@ await Network.WaitForHttpOk($"http://localhost:{controlPort}/api", stopWaiting:
                 {
                     // HasExited can be true before all the error output has been read; this waits for the rest
                     await failedTool.Process.WaitForExitAsync(CancellationToken.None).ConfigureAwait(false);
-                    Console.WriteLine($"{failedTool.Name} failed to start:");
-                    Console.WriteLine(failedTool.ErrorOutput.ToString());
+                    Console.WriteLine($"{failedTool.Name} failed to start (exit code {failedTool.Process.ExitCode}):");
+
+                    // Nothing is captured when the tool output is shown in the console, or when the tool exits without writing to stderr
+                    var errorOutput = failedTool.ErrorOutput.ToString();
+                    Console.WriteLine(errorOutput.Length > 0
+                        ? errorOutput
+                        : $"No error output was captured. Check the console output above or the logs in {Path.Combine(finder.Root, ".logs")}{Environment.NewLine}");
                 }
 
                 launcher.StopProcesses();
+
+                // Launch() is usually the last call in the sample's Main, so this makes the process report the failure
+                Environment.ExitCode = 1;
                 return;
             }