From ba2bca4a9627989e338aa8fd3b409fd964efef86 Mon Sep 17 00:00:00 2001
From: Pavel Krymets <pavel@krymets.com>
Date: Thu, 27 Apr 2017 08:14:09 -0700
Subject: [PATCH] Run IHostingStartup's before materializing IConfiguration
 (#1052)

---
 .../WebHostBuilder.cs                         | 58 +++++++++----------
 .../WebHostBuilderTests.cs                    | 22 ++++++-
 2 files changed, 50 insertions(+), 30 deletions(-)

diff --git a/src/Microsoft.AspNetCore.Hosting/WebHostBuilder.cs b/src/Microsoft.AspNetCore.Hosting/WebHostBuilder.cs
index 5ae258f924..e721925937 100644
--- a/src/Microsoft.AspNetCore.Hosting/WebHostBuilder.cs
+++ b/src/Microsoft.AspNetCore.Hosting/WebHostBuilder.cs
@@ -273,35 +273,6 @@ namespace Microsoft.AspNetCore.Hosting
 
             _options = new WebHostOptions(_config);
 
-            var contentRootPath = ResolveContentRootPath(_options.ContentRootPath, AppContext.BaseDirectory);
-            var applicationName = _options.ApplicationName;
-
-            // Initialize the hosting environment
-            _hostingEnvironment.Initialize(applicationName, contentRootPath, _options);
-            _context.HostingEnvironment = _hostingEnvironment;
-
-            var services = new ServiceCollection();
-            services.AddSingleton(_hostingEnvironment);
-            services.AddSingleton(_context);
-
-            var builder = new ConfigurationBuilder()
-                .SetBasePath(_hostingEnvironment.ContentRootPath)
-                .AddInMemoryCollection(_config.AsEnumerable());
-
-            foreach (var configureAppConfiguration in _configureAppConfigurationBuilderDelegates)
-            {
-                configureAppConfiguration(_context, builder);
-            }
-
-            var configuration = builder.Build();
-            services.AddSingleton<IConfiguration>(configuration);
-            _context.Configuration = configuration;
-
-            // The configured ILoggerFactory is added as a singleton here. AddLogging below will not add an additional one.
-            var loggerFactory = _createLoggerFactoryDelegate?.Invoke(_context) ?? new LoggerFactory(configuration.GetSection("Logging"));
-            services.AddSingleton(loggerFactory);
-            _context.LoggerFactory = loggerFactory;
-
             if (!_options.PreventHostingStartup)
             {
                 var exceptions = new List<Exception>();
@@ -338,6 +309,35 @@ namespace Microsoft.AspNetCore.Hosting
                 }
             }
 
+            var contentRootPath = ResolveContentRootPath(_options.ContentRootPath, AppContext.BaseDirectory);
+            var applicationName = _options.ApplicationName;
+
+            // Initialize the hosting environment
+            _hostingEnvironment.Initialize(applicationName, contentRootPath, _options);
+            _context.HostingEnvironment = _hostingEnvironment;
+
+            var services = new ServiceCollection();
+            services.AddSingleton(_hostingEnvironment);
+            services.AddSingleton(_context);
+
+            var builder = new ConfigurationBuilder()
+                .SetBasePath(_hostingEnvironment.ContentRootPath)
+                .AddInMemoryCollection(_config.AsEnumerable());
+
+            foreach (var configureAppConfiguration in _configureAppConfigurationBuilderDelegates)
+            {
+                configureAppConfiguration(_context, builder);
+            }
+
+            var configuration = builder.Build();
+            services.AddSingleton<IConfiguration>(configuration);
+            _context.Configuration = configuration;
+
+            // The configured ILoggerFactory is added as a singleton here. AddLogging below will not add an additional one.
+            var loggerFactory = _createLoggerFactoryDelegate?.Invoke(_context) ?? new LoggerFactory(configuration.GetSection("Logging"));
+            services.AddSingleton(loggerFactory);
+            _context.LoggerFactory = loggerFactory;
+
             foreach (var configureLogging in _configureLoggingDelegates)
             {
                 configureLogging(_context, loggerFactory);
diff --git a/test/Microsoft.AspNetCore.Hosting.Tests/WebHostBuilderTests.cs b/test/Microsoft.AspNetCore.Hosting.Tests/WebHostBuilderTests.cs
index e5f809f3c5..4c5ff5b4bc 100644
--- a/test/Microsoft.AspNetCore.Hosting.Tests/WebHostBuilderTests.cs
+++ b/test/Microsoft.AspNetCore.Hosting.Tests/WebHostBuilderTests.cs
@@ -931,6 +931,21 @@ namespace Microsoft.AspNetCore.Hosting
             }
         }
 
+        [Fact]
+        public void Build_ConfigureAppConfigurationInHostingStartupWorks()
+        {
+            var builder = CreateWebHostBuilder()
+                .CaptureStartupErrors(false)
+                .Configure(app => { })
+                .UseServer(new TestServer());
+
+            using (var host = (WebHost)builder.Build())
+            {
+                var configuration = host.Services.GetRequiredService<IConfiguration>();
+                Assert.Equal("value", configuration["testhostingstartup:config"]);
+            }
+        }
+
         [Fact]
         public void Build_DoesRunHostingStartupFromPrimaryAssemblyEvenIfNotSpecified()
         {
@@ -1089,7 +1104,12 @@ namespace Microsoft.AspNetCore.Hosting
                        .UseSetting("testhostingstartup_chain", builder.GetSetting("testhostingstartup_chain") + "0")
                        .ConfigureServices(services => services.AddSingleton<ServiceA>())
                        .ConfigureServices(services => services.AddSingleton<ITestSink>(loggerProvider.Sink))
-                       .ConfigureLogging(lf => lf.AddProvider(loggerProvider));
+                       .ConfigureLogging(lf => lf.AddProvider(loggerProvider))
+                       .ConfigureAppConfiguration((context, configurationBuilder) => configurationBuilder.AddInMemoryCollection(
+                           new []
+                           {
+                               new KeyValuePair<string,string>("testhostingstartup:config", "value")
+                           }));
             }
         }