Add ILogger support for TryRefreshAsync in .NET Core package (#273)

src/Microsoft.Extensions.Configuration.AzureAppConfiguration/AzureAppConfigurationExtensions.cs

@@ -54,6 +54,7 @@ public static IServiceCollection AddAzureAppConfiguration(this IServiceCollectio
                 throw new ArgumentNullException(nameof(services));
             }
 
+            services.AddLogging();
             services.AddSingleton<IConfigurationRefresherProvider, AzureAppConfigurationRefresherProvider>();
             return services;
         }

src/Microsoft.Extensions.Configuration.AzureAppConfiguration/AzureAppConfigurationProvider.cs

@@ -6,6 +6,7 @@
 using Microsoft.Extensions.Configuration.AzureAppConfiguration.Extensions;
 using Microsoft.Extensions.Configuration.AzureAppConfiguration.FeatureManagement;
 using Microsoft.Extensions.Configuration.AzureAppConfiguration.Models;
+using Microsoft.Extensions.Logging;
 using System;
 using System.Collections.Generic;
 using System.Diagnostics;
@@ -18,7 +19,6 @@
 
 namespace Microsoft.Extensions.Configuration.AzureAppConfiguration
 {
-
     internal class AzureAppConfigurationProvider : ConfigurationProvider, IConfigurationRefresher
     {
         private bool _optional;
@@ -41,6 +41,8 @@ internal class AzureAppConfigurationProvider : ConfigurationProvider, IConfigura
 
         // To avoid concurrent network operations, this flag is used to achieve synchronization between multiple threads.
         private int _networkOperationsInProgress = 0;
+        private ILogger _logger;
+        private ILoggerFactory _loggerFactory;
 
         public Uri AppConfigurationEndpoint
         {
@@ -68,6 +70,19 @@ public Uri AppConfigurationEndpoint
             }
         }
 
+        public ILoggerFactory LoggerFactory
+        {
+            get
+            {
+                return _loggerFactory;
+            }
+            set
+            {
+                _loggerFactory = value;
+                _logger = _loggerFactory?.CreateLogger(LoggingConstants.AppConfigRefreshLogCategory);
+            }
+        }
+
         public AzureAppConfigurationProvider(ConfigurationClient client, AzureAppConfigurationOptions options, bool optional)
         {
             _client = client ?? throw new ArgumentNullException(nameof(client));
@@ -182,12 +197,40 @@ public async Task<bool> TryRefreshAsync()
             {
                 await RefreshAsync().ConfigureAwait(false);
             }
-            catch (Exception e) when (
-                e is KeyVaultReferenceException ||
-                e is RequestFailedException ||
-                ((e as AggregateException)?.InnerExceptions?.All(e => e is RequestFailedException) ?? false) ||
-                e is OperationCanceledException)
+            catch (RequestFailedException e)
             {
+                if (IsAuthenticationError(e))
+                {
+                    _logger?.LogWarning(e, LoggingConstants.RefreshFailedDueToAuthenticationError);
+                }
+                else
+                {
+                    _logger?.LogWarning(e, LoggingConstants.RefreshFailedError);
+                }
+
+                return false;
+            }
+            catch (AggregateException e) when (e?.InnerExceptions?.All(e => e is RequestFailedException) ?? false)
+            {
+                if (IsAuthenticationError(e))
+                {
+                    _logger?.LogWarning(e, LoggingConstants.RefreshFailedDueToAuthenticationError);
+                }
+                else
+                {
+                    _logger?.LogWarning(e, LoggingConstants.RefreshFailedError);
+                }
+
+                return false;
+            }
+            catch (KeyVaultReferenceException e)
+            {
+                _logger?.LogWarning(e, LoggingConstants.RefreshFailedDueToKeyVaultError);
+                return false;
+            }
+            catch (OperationCanceledException)
+            {
+                _logger?.LogWarning(LoggingConstants.RefreshCanceledError);
                 return false;
             }
 
@@ -634,5 +677,20 @@ private DateTimeOffset AddRandomDelay(DateTimeOffset dt, TimeSpan maxDelay)
             long randomTicks = (long)(maxDelay.Ticks * RandomGenerator.NextDouble());
             return dt.AddTicks(randomTicks);
         }
+
+        private bool IsAuthenticationError(Exception ex)
+        {
+            if (ex is RequestFailedException rfe)
+            {
+                return rfe.Status == (int)HttpStatusCode.Unauthorized || rfe.Status == (int)HttpStatusCode.Forbidden;
+            }
+
+            if (ex is AggregateException ae)
+            {
+                return ae.InnerExceptions?.Any(inner => IsAuthenticationError(inner)) ?? false;
+            }
+
+            return false;
+        }
     }
 }

src/Microsoft.Extensions.Configuration.AzureAppConfiguration/AzureAppConfigurationRefresher.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT license.
 //
+using Microsoft.Extensions.Logging;
 using System;
 using System.Threading.Tasks;
 
@@ -11,6 +12,19 @@ internal class AzureAppConfigurationRefresher : IConfigurationRefresher
         private AzureAppConfigurationProvider _provider = null;
 
         public Uri AppConfigurationEndpoint { get; private set; } = null;
+
+        public ILoggerFactory LoggerFactory { 
+            get 
+            {
+                ThrowIfNullProvider(nameof(LoggerFactory));
+                return _provider.LoggerFactory;
+            }
+            set 
+            { 
+                ThrowIfNullProvider(nameof(LoggerFactory)); 
+                _provider.LoggerFactory = value;
+            } 
+        }
 
         public void SetProvider(AzureAppConfigurationProvider provider)
         {
@@ -20,7 +34,7 @@ public void SetProvider(AzureAppConfigurationProvider provider)
 
         public async Task RefreshAsync()
         {
-            ThrowIfNullProvider();
+            ThrowIfNullProvider(nameof(RefreshAsync));
             await _provider.RefreshAsync().ConfigureAwait(false);
         }
 
@@ -36,15 +50,15 @@ public async Task<bool> TryRefreshAsync()
 
         public void SetDirty(TimeSpan? maxDelay)
         {
-            ThrowIfNullProvider();
+            ThrowIfNullProvider(nameof(SetDirty));
             _provider.SetDirty(maxDelay);
         }
 
-        private void ThrowIfNullProvider()
+        private void ThrowIfNullProvider(string operation)
         {
             if (_provider == null)
             {
-                throw new InvalidOperationException("ConfigurationBuilder.Build() must be called before this operation can be performed.");
+                throw new InvalidOperationException($"ConfigurationBuilder.Build() must be called before {operation} can be accessed.");
             }
         }
     }

src/Microsoft.Extensions.Configuration.AzureAppConfiguration/AzureAppConfigurationRefresherProvider.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT license.
 //
+using Microsoft.Extensions.Logging;
 using System;
 using System.Collections.Generic;
 using System.Linq;
@@ -11,7 +12,7 @@ internal class AzureAppConfigurationRefresherProvider : IConfigurationRefresherP
     {
         public IEnumerable<IConfigurationRefresher> Refreshers { get; }
 
-        public AzureAppConfigurationRefresherProvider(IConfiguration configuration)
+        public AzureAppConfigurationRefresherProvider(IConfiguration configuration, ILoggerFactory _loggerFactory)
         {
             var configurationRoot = configuration as IConfigurationRoot;
             var refreshers = new List<IConfigurationRefresher>();
@@ -22,6 +23,12 @@ public AzureAppConfigurationRefresherProvider(IConfiguration configuration)
                 {
                     if (provider is IConfigurationRefresher refresher)
                     {
+                        // Use _loggerFactory only if LoggerFactory hasn't been set in AzureAppConfigurationOptions
+                        if (refresher.LoggerFactory == null)
+                        {
+                            refresher.LoggerFactory = _loggerFactory;
+                        }
+
                         refreshers.Add(refresher);
                     }
                 }

src/Microsoft.Extensions.Configuration.AzureAppConfiguration/Constants/LoggingConstants.cs

@@ -0,0 +1,17 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+//
+namespace Microsoft.Extensions.Configuration.AzureAppConfiguration
+{
+    internal class LoggingConstants
+    {
+        // Categories
+        public const string AppConfigRefreshLogCategory = "Microsoft.Extensions.Configuration.AzureAppConfiguration.Refresh";
+
+        // Error messages
+        public const string RefreshFailedDueToAuthenticationError = "A refresh operation failed due to an authentication error.";
+        public const string RefreshFailedDueToKeyVaultError = "A refresh operation failed while resolving a Key Vault reference.";
+        public const string RefreshFailedError = "A refresh operation failed.";
+        public const string RefreshCanceledError = "A refresh operation was canceled.";
+    }
+}

src/Microsoft.Extensions.Configuration.AzureAppConfiguration/IConfigurationRefresher.cs

@@ -2,6 +2,7 @@
 // Licensed under the MIT license.
 //
 using Azure;
+using Microsoft.Extensions.Logging;
 using System;
 using System.Threading.Tasks;
 
@@ -17,6 +18,11 @@ public interface IConfigurationRefresher
         /// </summary>
         Uri AppConfigurationEndpoint { get; }
 
+        /// <summary>
+        /// An <see cref="ILoggerFactory"/> for creating a logger to log errors.
+        /// </summary>
+        ILoggerFactory LoggerFactory { get; set; }
+
         /// <summary>
         /// Refreshes the data from App Configuration asynchronously.
         /// </summary>

src/Microsoft.Extensions.Configuration.AzureAppConfiguration/Microsoft.Extensions.Configuration.AzureAppConfiguration.csproj

@@ -18,6 +18,7 @@
     <PackageReference Include="Azure.Security.KeyVault.Secrets" Version="4.0.1" />
     <PackageReference Include="Microsoft.Extensions.Configuration" Version="3.1.18" />
     <PackageReference Include="Microsoft.Extensions.DependencyInjection.Abstractions" Version="3.1.18" />
+    <PackageReference Include="Microsoft.Extensions.Logging" Version="3.1.18" />
     <PackageReference Include="System.Text.Json" Version="4.6.0" />
   </ItemGroup>