Resetting root configuration on specialization

Author: fabiocav

src/WebJobs.Script.WebHost/Standby/StandbyManager.cs

@@ -10,6 +10,7 @@
 using Microsoft.AspNetCore.Http;
 using Microsoft.Azure.WebJobs.Logging;
 using Microsoft.Azure.WebJobs.Script.Extensions;
+using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.FileProviders;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Options;
@@ -25,17 +26,20 @@ public class StandbyManager : IStandbyManager
         private readonly IScriptHostManager _scriptHostManager;
         private readonly IOptionsMonitor<ScriptApplicationHostOptions> _options;
         private readonly Lazy<Task> _specializationTask;
+        private readonly IConfigurationRoot _configuration;
         private readonly ILogger _logger;
         private static CancellationTokenSource _standbyCancellationTokenSource = new CancellationTokenSource();
         private static IChangeToken _standbyChangeToken = new CancellationChangeToken(_standbyCancellationTokenSource.Token);
         private static SemaphoreSlim _semaphore = new SemaphoreSlim(1, 1);
 
-        public StandbyManager(IScriptHostManager scriptHostManager, IOptionsMonitor<ScriptApplicationHostOptions> options, ILoggerFactory loggerFactory)
+        public StandbyManager(IScriptHostManager scriptHostManager, IConfiguration configuration, IOptionsMonitor<ScriptApplicationHostOptions> options, ILoggerFactory loggerFactory)
         {
             _scriptHostManager = scriptHostManager ?? throw new ArgumentNullException(nameof(scriptHostManager));
             _options = options ?? throw new ArgumentNullException(nameof(options));
             _logger = loggerFactory.CreateLogger(LogCategories.Startup);
             _specializationTask = new Lazy<Task>(SpecializeHostCoreAsync, LazyThreadSafetyMode.ExecutionAndPublication);
+
+            _configuration = configuration as IConfigurationRoot;
         }
 
         public static IChangeToken ChangeToken => _standbyChangeToken;
@@ -47,6 +51,9 @@ public Task SpecializeHostAsync()
 
         public async Task SpecializeHostCoreAsync()
         {
+            // Trigger a configuration reload to pick up all current settings
+            _configuration?.Reload();
+
             NotifyChange();
 
             await _scriptHostManager.RestartHostAsync();

test/WebJobs.Script.Tests/StandbyManagerTests.cs

@@ -0,0 +1,37 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT License. See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using System.Text;
+using System.Threading.Tasks;
+using Microsoft.Azure.WebJobs.Script.WebHost;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Options;
+using Moq;
+using Xunit;
+
+namespace Microsoft.Azure.WebJobs.Script.Tests
+{
+    public class StandbyManagerTests
+    {
+        [Fact]
+        public async Task Specialize_ResetsConfiguration()
+        {
+            var mockHostManager = new Mock<IScriptHostManager>();
+            mockHostManager.Setup(m => m.State)
+                .Returns(ScriptHostState.Running);
+
+            var mockConfiguration = new Mock<IConfigurationRoot>();
+            var mockOptionsMonitor = new Mock<IOptionsMonitor<ScriptApplicationHostOptions>>();
+            var mockLoggerFactory = new Mock<ILoggerFactory>();
+
+            var manager = new StandbyManager(mockHostManager.Object, mockConfiguration.Object, mockOptionsMonitor.Object, mockLoggerFactory.Object);
+
+            await manager.SpecializeHostAsync();
+
+            mockConfiguration.Verify(c => c.Reload());
+        }
+    }
+}