SetBasePath earlier. Copy sources once

Author: halter73

src/DefaultBuilder/src/BootstrapHostBuilder.cs

@@ -17,6 +17,9 @@ internal class BootstrapHostBuilder : IHostBuilder
         private readonly Configuration _configuration;
         private readonly WebHostEnvironment _environment;
 
+        private readonly List<Action<IConfigurationBuilder>> _configureHostActions = new List<Action<IConfigurationBuilder>>();
+        private readonly List<Action<HostBuilderContext, IConfigurationBuilder>> _configureAppActions = new List<Action<HostBuilderContext, IConfigurationBuilder>>();
+
         public BootstrapHostBuilder(Configuration configuration, WebHostEnvironment webHostEnvironment)
         {
             _configuration = configuration;
@@ -38,8 +41,7 @@ public IHost Build()
 
         public IHostBuilder ConfigureAppConfiguration(Action<HostBuilderContext, IConfigurationBuilder> configureDelegate)
         {
-            configureDelegate(_context, _configuration);
-            _environment.ApplyConfigurationSettings(_configuration);
+            _configureAppActions.Add(configureDelegate ?? throw new ArgumentNullException(nameof(configureDelegate)));
             return this;
         }
 
@@ -52,8 +54,7 @@ public IHostBuilder ConfigureContainer<TContainerBuilder>(Action<HostBuilderCont
 
         public IHostBuilder ConfigureHostConfiguration(Action<IConfigurationBuilder> configureDelegate)
         {
-            configureDelegate(_configuration);
-            _environment.ApplyConfigurationSettings(_configuration);
+            _configureHostActions.Add(configureDelegate ?? throw new ArgumentNullException(nameof(configureDelegate)));
             return this;
         }
 
@@ -66,7 +67,7 @@ public IHostBuilder ConfigureServices(Action<HostBuilderContext, IServiceCollect
 
         public IHostBuilder UseServiceProviderFactory<TContainerBuilder>(IServiceProviderFactory<TContainerBuilder> factory) where TContainerBuilder : notnull
         {
-            // This is not called by HostingHostBuilderExtensions.ConfigureDefaults currently, but that chould change in the future.
+            // This is not called by HostingHostBuilderExtensions.ConfigureDefaults currently, but that could change in the future.
             // If this does get called in the future, it should be called again at a later stage on the ConfigureHostBuilder.
             return this;
         }
@@ -77,5 +78,22 @@ public IHostBuilder UseServiceProviderFactory<TContainerBuilder>(Func<HostBuilde
             // during the initial config stage. It should be called again later on the ConfigureHostBuilder.
             return this;
         }
+
+        internal void ExecuteActions()
+        {
+            foreach (var configureHostAction in _configureHostActions)
+            {
+                configureHostAction(_configuration);
+            }
+
+            _environment.ApplyConfigurationSettings(_configuration);
+
+            foreach (var configureAppAction in _configureAppActions)
+            {
+                configureAppAction(_context, _configuration);
+            }
+
+            _environment.ApplyConfigurationSettings(_configuration);
+        }
     }
 }

src/DefaultBuilder/src/Configuration.cs

@@ -91,15 +91,15 @@ private ConfigurationRoot BuildConfigurationRoot()
             var providers = new List<IConfigurationProvider>();
             foreach (var source in _sources)
             {
-                IConfigurationProvider provider = source.Build(this);
+                var provider = source.Build(this);
                 providers.Add(provider);
             }
             return new ConfigurationRoot(providers);
         }
 
         private void RaiseChanged()
         {
-            ConfigurationReloadToken previousToken = Interlocked.Exchange(ref _changeToken, new ConfigurationReloadToken());
+            var previousToken = Interlocked.Exchange(ref _changeToken, new ConfigurationReloadToken());
             previousToken.OnReload();
         }
 

src/DefaultBuilder/src/ConfigureHostBuilder.cs

@@ -20,21 +20,27 @@ public sealed class ConfigureHostBuilder : IHostBuilder
         /// <inheritdoc />
         public IDictionary<object, object> Properties { get; } = new Dictionary<object, object>();
 
-        internal Configuration Configuration => _configuration;
-
-        private readonly IConfigurationBuilder _hostConfiguration = new ConfigurationBuilder();
-
         private readonly WebHostEnvironment _environment;
         private readonly Configuration _configuration;
         private readonly IServiceCollection _services;
 
+        private readonly HostBuilderContext _context;
+
         internal ConfigureHostBuilder(Configuration configuration, WebHostEnvironment environment, IServiceCollection services)
         {
             _configuration = configuration;
             _environment = environment;
             _services = services;
+
+            _context = new HostBuilderContext(Properties)
+            {
+                Configuration = _configuration,
+                HostingEnvironment = _environment
+            };
         }
 
+        internal bool ConfigurationEnabled { get; set; }
+
         IHost IHostBuilder.Build()
         {
             throw new NotSupportedException($"Call {nameof(WebApplicationBuilder)}.{nameof(WebApplicationBuilder.Build)}() instead.");
@@ -43,7 +49,13 @@ IHost IHostBuilder.Build()
         /// <inheritdoc />
         public IHostBuilder ConfigureAppConfiguration(Action<HostBuilderContext, IConfigurationBuilder> configureDelegate)
         {
-            _operations += b => b.ConfigureAppConfiguration(configureDelegate);
+            if (ConfigurationEnabled)
+            {
+                // Run these immediately so that they are observable by the imperative code
+                configureDelegate(_context, _configuration);
+                _environment.ApplyConfigurationSettings(_configuration);
+            }
+
             return this;
         }
 
@@ -57,10 +69,12 @@ public IHostBuilder ConfigureContainer<TContainerBuilder>(Action<HostBuilderCont
         /// <inheritdoc />
         public IHostBuilder ConfigureHostConfiguration(Action<IConfigurationBuilder> configureDelegate)
         {
-            // HACK: We need to evaluate the host configuration as they are changes so that we have an accurate view of the world
-            configureDelegate(_hostConfiguration);
-
-            _environment.ApplyConfigurationSettings(_hostConfiguration.Build());
+            if (ConfigurationEnabled)
+            {
+                // Run these immediately so that they are observable by the imperative code
+                configureDelegate(_configuration);
+                _environment.ApplyConfigurationSettings(_configuration);
+            }
 
             return this;
         }
@@ -69,12 +83,7 @@ public IHostBuilder ConfigureHostConfiguration(Action<IConfigurationBuilder> con
         public IHostBuilder ConfigureServices(Action<HostBuilderContext, IServiceCollection> configureDelegate)
         {
             // Run these immediately so that they are observable by the imperative code
-            configureDelegate(new HostBuilderContext(Properties)
-            {
-                Configuration = Configuration,
-                HostingEnvironment = _environment
-            },
-            _services);
+            configureDelegate(_context, _services);
 
             return this;
         }

src/DefaultBuilder/src/WebApplicationBuilder.cs

@@ -29,23 +29,29 @@ internal WebApplicationBuilder(Assembly? callingAssembly, string[]? args = null)
             // from the service collection before it is built. That needs to be fixed...
             Environment = _environment = new WebHostEnvironment(callingAssembly);
 
+            Configuration.SetBasePath(_environment.ContentRootPath);
             Services.AddSingleton(Environment);
 
             // Run methods to configure both generic and web host defaults early to populate config from appsettings.json
             // environment variables (both DOTNET_ and ASPNETCORE_ prefixed) and other possible default sources to prepopulate
             // the correct defaults.
             var bootstrapBuilder = new BootstrapHostBuilder(Configuration, _environment);
-            bootstrapBuilder.ConfigureWebHostDefaults(configure: _ => { });
             bootstrapBuilder.ConfigureDefaults(args);
+            bootstrapBuilder.ConfigureWebHostDefaults(configure: _ => { });
+            bootstrapBuilder.ExecuteActions();
 
-            Configuration.SetBasePath(_environment.ContentRootPath);
             Logging = new LoggingBuilder(Services);
             WebHost = _deferredWebHostBuilder = new ConfigureWebHostBuilder(Configuration, _environment, Services);
             Host = _deferredHostBuilder = new ConfigureHostBuilder(Configuration, _environment, Services);
 
+            // Register Configuration as IConfiguration so updates can be observed even after the WebApplication is built.
             Services.AddSingleton<IConfiguration>(Configuration);
 
+            // Add default services
             _deferredHostBuilder.ConfigureDefaults(args);
+            // Configuration changes made by ConfigureDefaults(args) were already picked up by the BootstrapHostBuilder,
+            // so we ignore changes to config until ConfigureDefaults completes.
+            _deferredHostBuilder.ConfigurationEnabled = true;
         }
 
         /// <summary>
@@ -158,17 +164,7 @@ private void ConfigureApplication(WebHostBuilderContext context, IApplicationBui
 
         private void ConfigureWebHost(IWebHostBuilder genericWebHostBuilder)
         {
-            genericWebHostBuilder.Configure(ConfigureApplication);
-
-            _hostBuilder.ConfigureServices((context, services) =>
-            {
-                foreach (var s in Services)
-                {
-                    services.Add(s);
-                }
-            });
-
-            _hostBuilder.ConfigureAppConfiguration((hostContext, builder) =>
+            _hostBuilder.ConfigureHostConfiguration(builder =>
             {
                 // All the sources in builder.Sources should be in Configuration.Sources
                 // already thanks to the BootstrapHostBuilder.
@@ -180,6 +176,16 @@ private void ConfigureWebHost(IWebHostBuilder genericWebHostBuilder)
                 }
             });
 
+            _hostBuilder.ConfigureServices((context, services) =>
+            {
+                foreach (var s in Services)
+                {
+                    services.Add(s);
+                }
+            });
+
+            genericWebHostBuilder.Configure(ConfigureApplication);
+
             _deferredHostBuilder.ExecuteActions(_hostBuilder);
             _deferredWebHostBuilder.ExecuteActions(genericWebHostBuilder);