Add nice error page for boot, like in v8

src/Umbraco.Core/Configuration/Models/UnattendedSettings.cs

@@ -19,6 +19,12 @@ namespace Umbraco.Cms.Core.Configuration.Models
         /// </remarks>
         public bool InstallUnattended { get; set; } = false;
 
+        /// <summary>
+        /// Gets or sets a value indicating whether unattended upgrades are enabled.
+        /// </summary>
+        public bool UpgradeUnattended { get; set; } = false;
+
+
         /// <summary>
         /// Gets or sets a value to use for creating a user with a name for Unattended Installs
         /// </summary>

src/Umbraco.Infrastructure/Runtime/CoreRuntime.cs

@@ -14,7 +14,6 @@ using Umbraco.Cms.Core.Services;
 using Umbraco.Cms.Infrastructure.Migrations.Install;
 using Umbraco.Cms.Infrastructure.Migrations.Upgrade;
 using Umbraco.Cms.Infrastructure.Persistence;
-using Constants = Umbraco.Cms.Core.Constants;
 
 namespace Umbraco.Cms.Infrastructure.Runtime
 {
@@ -96,7 +95,7 @@ namespace Umbraco.Cms.Infrastructure.Runtime
 
             if (State.Level <= RuntimeLevel.BootFailed)
             {
-                throw new InvalidOperationException($"Cannot start the runtime if the runtime level is less than or equal to {RuntimeLevel.BootFailed}");
+                return; // The exception will be rethrown by BootFailedMiddelware
             }
 
             IApplicationShutdownRegistry hostingEnvironmentLifetime = _applicationShutdownRegistry;
@@ -110,8 +109,8 @@ namespace Umbraco.Cms.Infrastructure.Runtime
 
             await _eventAggregator.PublishAsync(new UmbracoApplicationStarting(State.Level), cancellationToken);
 
-            // if level is Updrade and reason is UpgradeMigrations, that means we need to perform an unattended upgrade
-            if (State.Reason == RuntimeLevelReason.UpgradeMigrations && State.Level == RuntimeLevel.Upgrade)
+            // if level is Run and reason is UpgradeMigrations, that means we need to perform an unattended upgrade
+            if (State.Reason == RuntimeLevelReason.UpgradeMigrations && State.Level == RuntimeLevel.Run)
             {
                 // do the upgrade
                 DoUnattendedUpgrade();
@@ -181,11 +180,12 @@ namespace Umbraco.Cms.Infrastructure.Runtime
                     _databaseFactory.ConfigureForUpgrade();
                 }
             }
-            catch
+            catch (Exception ex)
             {
                 State.Configure(RuntimeLevel.BootFailed, RuntimeLevelReason.BootFailedOnException);
                 timer?.Fail();
-                throw;
+                _logger.LogError(ex, "Boot Failed");
+                // We do not throw the exception. It will be rethrown by BootFailedMiddleware
             }
         }
     }

src/Umbraco.Infrastructure/RuntimeState.cs

@@ -116,7 +116,8 @@ namespace Umbraco.Cms.Core
 
                         // else it is bad enough that we want to throw
                         Reason = RuntimeLevelReason.BootFailedCannotConnectToDatabase;
-                        throw new BootFailedException("A connection string is configured but Umbraco could not connect to the database.");
+                        BootFailedException =new BootFailedException("A connection string is configured but Umbraco could not connect to the database.");
+                        throw BootFailedException;
                     }
                 case UmbracoDatabaseState.NotInstalled:
                     {
@@ -133,7 +134,7 @@ namespace Umbraco.Cms.Core
                         // although the files version matches the code version, the database version does not
                         // which means the local files have been upgraded but not the database - need to upgrade
                         _logger.LogDebug("Has not reached the final upgrade step, need to upgrade Umbraco.");
-                        Level = RuntimeLevel.Upgrade;
+                        Level = _unattendedSettings.Value.UpgradeUnattended ? RuntimeLevel.Run : RuntimeLevel.Upgrade;
                         Reason = RuntimeLevelReason.UpgradeMigrations;
                     }
                     break;
@@ -192,7 +193,8 @@ namespace Umbraco.Cms.Core
 
                 // else it is bad enough that we want to throw
                 Reason = RuntimeLevelReason.BootFailedCannotCheckUpgradeState;
-                throw new BootFailedException("Could not check the upgrade state.", e);
+                BootFailedException = new BootFailedException("Could not check the upgrade state.", e);
+                throw BootFailedException;
             }
         }
 
@@ -251,9 +253,12 @@ namespace Umbraco.Cms.Core
                     _logger.LogInformation(ex, "Error during unattended install.");
                     database.AbortTransaction();
 
-                    throw new UnattendedInstallException(
+                    var innerException = new UnattendedInstallException(
                         "The database configuration failed with the following message: " + ex.Message
                         + "\n Please check log file for additional information (can be found in '/App_Data/Logs/')");
+                    BootFailedException = new BootFailedException(innerException.Message, innerException);
+
+                    throw BootFailedException;
                 }
             }
         }

src/Umbraco.Web.Common/Extensions/ApplicationBuilderExtensions.cs

@@ -121,6 +121,7 @@ namespace Umbraco.Extensions
 
             if (!app.UmbracoCanBoot())
             {
+                app.UseStaticFiles(); // We need static files to show the nice error page.
                 app.UseMiddleware<BootFailedMiddleware>();
             }
             else

src/Umbraco.Web.Common/Middleware/BootFailedMiddleware.cs

@@ -1,7 +1,10 @@
+using System.IO;
+using System.Text;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Http;
 using Umbraco.Cms.Core;
 using Umbraco.Cms.Core.Exceptions;
+using Umbraco.Cms.Core.Hosting;
 using Umbraco.Cms.Core.Services;
 
 namespace Umbraco.Cms.Web.Common.Middleware
@@ -12,10 +15,12 @@ namespace Umbraco.Cms.Web.Common.Middleware
     public class BootFailedMiddleware : IMiddleware
     {
         private readonly IRuntimeState _runtimeState;
+        private readonly IHostingEnvironment _hostingEnvironment;
 
-        public BootFailedMiddleware(IRuntimeState runtimeState)
+        public BootFailedMiddleware(IRuntimeState runtimeState, IHostingEnvironment hostingEnvironment)
         {
             _runtimeState = runtimeState;
+            _hostingEnvironment = hostingEnvironment;
         }
 
         public async Task InvokeAsync(HttpContext context, RequestDelegate next)
@@ -23,12 +28,35 @@ namespace Umbraco.Cms.Web.Common.Middleware
             if (_runtimeState.Level == RuntimeLevel.BootFailed)
             {
                 // short circuit
-                BootFailedException.Rethrow(_runtimeState.BootFailedException);
+                //
+
+                if (_hostingEnvironment.IsDebugMode)
+                {
+                    BootFailedException.Rethrow(_runtimeState.BootFailedException);
+                }
+                else  // Print a nice error page
+                {
+                    context.Response.Clear();
+                    context.Response.StatusCode = 500;
+
+                    var file = GetBootErrorFileName();
+
+                    var viewContent = await File.ReadAllTextAsync(file);
+                    await context.Response.WriteAsync(viewContent, Encoding.UTF8);
+                }
             }
             else
             {
                 await next(context);
             }
+
+        }
+        private string GetBootErrorFileName()
+        {
+            var fileName = _hostingEnvironment.MapPathWebRoot("~/config/errors/BootFailed.html");
+            if (File.Exists(fileName)) return fileName;
+
+            return _hostingEnvironment.MapPathWebRoot("~/umbraco/views/errors/BootFailed.html");
         }
     }
 }