Fix memory leak: RuntimeConfigProvider._changeTokenRegistration never disposed

src/Core/Configurations/RuntimeConfigProvider.cs

@@ -25,7 +25,7 @@ namespace Azure.DataApiBuilder.Core.Configurations;
 /// should not load the config directly, or maintain a reference to it, so that we can do hot-reloading by replacing
 /// the config that is available from this type.
 /// </remarks>
-public class RuntimeConfigProvider
+public class RuntimeConfigProvider : IDisposable
 {
     public delegate Task<bool> RuntimeConfigLoadedHandler(RuntimeConfigProvider sender, RuntimeConfig config);
 
@@ -46,6 +46,7 @@ public class RuntimeConfigProvider
     private RuntimeConfigLoader _configLoader;
     private DabChangeToken _changeToken = new();
     private readonly IDisposable _changeTokenRegistration;
+    private bool _disposed;
 
     public RuntimeConfigProvider(RuntimeConfigLoader runtimeConfigLoader)
     {
@@ -89,6 +90,12 @@ public IChangeToken GetChangeToken()
     /// </summary>
     public void Dispose()
     {
+        if (_disposed)
+        {
+            return;
+        }
+
+        _disposed = true;
         _changeTokenRegistration.Dispose();
     }
 

src/Service.Tests/Authentication/Helpers/WebHostBuilderHelper.cs

@@ -80,7 +80,7 @@ public static async Task<IHost> CreateWebHost(
                                     .AddEasyAuthAuthentication(easyAuthProvider);
                             }
 
-                            services.AddSingleton(runtimeConfigProvider);
+                            services.AddSingleton<RuntimeConfigProvider>(sp => runtimeConfigProvider);
 
                             // https://github.com/dotnet/aspnetcore/issues/53332#issuecomment-2091861884
                             // AddRouting() adds required services that .NET8 does not add by default
@@ -179,7 +179,7 @@ public static async Task<IHost> CreateWebHostCustomIssuer(SecurityKey key)
                                     };
                                 });
                             services.AddAuthorization();
-                            services.AddSingleton(runtimeConfigProvider);
+                            services.AddSingleton<RuntimeConfigProvider>(sp => runtimeConfigProvider);
                         })
                         .ConfigureLogging(o =>
                         {

src/Service.Tests/Authentication/JwtTokenAuthenticationUnitTests.cs

@@ -347,7 +347,7 @@ private static async Task<IHost> CreateWebHostCustomIssuer(SecurityKey key)
                                     };
                                 });
                             services.AddAuthorization();
-                            services.AddSingleton(runtimeConfigProvider);
+                            services.AddSingleton<RuntimeConfigProvider>(sp => runtimeConfigProvider);
                         })
                         .ConfigureLogging(o =>
                         {

src/Service.Tests/CosmosTests/TestBase.cs

@@ -174,8 +174,8 @@ protected WebApplicationFactory<Startup> SetupTestApplicationFactory()
                 _ = builder.ConfigureTestServices(services =>
                 {
                     services.AddSingleton<IFileSystem>(fileSystem);
-                    services.AddSingleton(loader);
-                    services.AddSingleton(provider);
+                    services.AddSingleton<FileSystemRuntimeConfigLoader>(sp => loader);
+                    services.AddSingleton<RuntimeConfigProvider>(sp => provider);
                     services.AddSingleton(authorizationResolverCosmos);
                 });
             });

src/Service.Tests/Mcp/AggregateRecordsToolTests.cs

@@ -665,7 +665,7 @@ private static IServiceProvider CreateServiceProvider(RuntimeConfig config)
             ServiceCollection services = new();
 
             RuntimeConfigProvider configProvider = TestHelper.GenerateInMemoryRuntimeConfigProvider(config);
-            services.AddSingleton(configProvider);
+            services.AddSingleton<RuntimeConfigProvider>(sp => configProvider);
 
             Mock<IAuthorizationResolver> mockAuthResolver = new();
             mockAuthResolver.Setup(x => x.IsValidRoleContext(It.IsAny<HttpContext>())).Returns(true);

src/Service.Tests/Mcp/DescribeEntitiesFilteringTests.cs

@@ -457,7 +457,7 @@ private static IServiceProvider CreateServiceProvider(RuntimeConfig config)
 
             // Use shared test helper to create RuntimeConfigProvider
             RuntimeConfigProvider configProvider = TestHelper.GenerateInMemoryRuntimeConfigProvider(config);
-            services.AddSingleton(configProvider);
+            services.AddSingleton<RuntimeConfigProvider>(sp => configProvider);
 
             // Mock IAuthorizationResolver
             Mock<IAuthorizationResolver> mockAuthResolver = new();

src/Service.Tests/Mcp/EntityLevelDmlToolConfigurationTests.cs

@@ -447,7 +447,7 @@ private static IServiceProvider CreateServiceProvider(RuntimeConfig config)
             ServiceCollection services = new();
 
             RuntimeConfigProvider configProvider = TestHelper.GenerateInMemoryRuntimeConfigProvider(config);
-            services.AddSingleton(configProvider);
+            services.AddSingleton<RuntimeConfigProvider>(sp => configProvider);
 
             Mock<IAuthorizationResolver> mockAuthResolver = new();
             mockAuthResolver.Setup(x => x.IsValidRoleContext(It.IsAny<HttpContext>())).Returns(true);

src/Service.Tests/Mcp/McpQueryTimeoutTests.cs

@@ -203,7 +203,7 @@ private static IServiceProvider CreateServiceProviderWithConfig(RuntimeConfig co
         {
             ServiceCollection services = new();
             RuntimeConfigProvider configProvider = TestHelper.GenerateInMemoryRuntimeConfigProvider(config);
-            services.AddSingleton(configProvider);
+            services.AddSingleton<RuntimeConfigProvider>(sp => configProvider);
             services.AddLogging();
             return services.BuildServiceProvider();
         }

src/Service.Tests/SqlTests/SqlTestBase.cs

@@ -178,7 +178,7 @@ protected async static Task InitializeTestFixture(
                     builder.ConfigureTestServices(services =>
                     {
                         services.AddHttpContextAccessor();
-                        services.AddSingleton(runtimeConfigProvider);
+                        services.AddSingleton<RuntimeConfigProvider>(sp => runtimeConfigProvider);
                         services.AddSingleton(_gqlFilterParser);
                         services.AddSingleton<IQueryEngine>(implementationFactory: serviceProvider =>
                         {

src/Service/Startup.cs

@@ -120,7 +120,7 @@ public void ConfigureServices(IServiceCollection services)
 
             services.AddSingleton(fileSystem);
             services.AddSingleton<FileSystemRuntimeConfigLoader>(sp => configLoader);
-            services.AddSingleton(configProvider);
+            services.AddSingleton<RuntimeConfigProvider>(sp => configProvider);
 
             bool runtimeConfigAvailable = configProvider.TryGetConfig(out RuntimeConfig? runtimeConfig);