add dashboard option to auto launch (#350)

src/Microsoft.Tye.Hosting/TyeHost.cs

@@ -4,10 +4,13 @@
 
 using System;
 using System.Collections.Generic;
+using System.CommandLine.Invocation;
+using System.Diagnostics;
 using System.Globalization;
 using System.Linq;
 using System.Net;
 using System.Net.Sockets;
+using System.Runtime.InteropServices;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.Extensions.Configuration;
@@ -98,6 +101,11 @@ namespace Microsoft.Tye.Hosting
 
             await _processor.StartAsync(_application);
 
+            if (_args.Contains("--dashboard"))
+            {
+                OpenDashboard(app.Addresses.First());
+            }
+
             return app;
         }
 
@@ -298,6 +306,31 @@ namespace Microsoft.Tye.Hosting
             _processor = null;
         }
 
+        private void OpenDashboard(string url)
+        {
+            try
+            {
+                // https://github.com/dotnet/corefx/issues/10361
+                if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+                {
+                    url = url.Replace("&", "^&");
+                    System.Diagnostics.Process.Start(new ProcessStartInfo("cmd", $"/c start {url}") { CreateNoWindow = true });
+                }
+                else if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
+                {
+                    System.Diagnostics.Process.Start("xdg-open", url);
+                }
+                else if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
+                {
+                    System.Diagnostics.Process.Start("open", url);
+                }
+            }
+            catch (Exception ex)
+            {
+                _logger.LogError(ex, "Error launching dashboard.");
+            }
+        }
+
         public async ValueTask DisposeAsync()
         {
             await StopAsync();

src/tye/Program.RunCommand.cs

@@ -64,6 +64,12 @@ namespace Microsoft.Tye
                 Required = false
             });
 
+            command.AddOption(new Option("--dashboard")
+            {
+                Description = "Launch dashboard on run.",
+                Required = false
+            });
+
             command.Handler = CommandHandler.Create<IConsole, FileInfo, string[]>(async (console, path, debug) =>
             {
                 // Workaround for https://github.com/dotnet/command-line-api/issues/723#issuecomment-593062654