Shorten default timeout of individual calls to backend

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

@@ -2,6 +2,7 @@
 // Licensed under the MIT license.
 //
 using Azure.Core;
+using Azure.Core.Pipeline;
 using Azure.Data.AppConfiguration;
 using Microsoft.Extensions.Configuration.AzureAppConfiguration.AzureKeyVault;
 using Microsoft.Extensions.Configuration.AzureAppConfiguration.Extensions;
@@ -10,6 +11,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Net.Http;
 using System.Threading.Tasks;
 
 namespace Microsoft.Extensions.Configuration.AzureAppConfiguration
@@ -18,10 +20,11 @@ namespace Microsoft.Extensions.Configuration.AzureAppConfiguration
     /// Options used to configure the behavior of an Azure App Configuration provider.         
     /// If neither <see cref="Select"/> nor <see cref="SelectSnapshot"/> is ever called, all key-values with no label are included in the configuration provider.
     /// </summary>
-    public class AzureAppConfigurationOptions
+    public class AzureAppConfigurationOptions : IDisposable
     {
         private const int MaxRetries = 2;
         private static readonly TimeSpan MaxRetryDelay = TimeSpan.FromMinutes(1);
+        private static readonly TimeSpan NetworkTimeout = TimeSpan.FromSeconds(10);
         private static readonly KeyValueSelector DefaultQuery = new KeyValueSelector { KeyFilter = KeyFilter.Any, LabelFilter = LabelFilter.Null };
 
         private List<KeyValueWatcher> _individualKvWatchers = new List<KeyValueWatcher>();
@@ -510,8 +513,23 @@ private static ConfigurationClientOptions GetDefaultClientOptions()
             clientOptions.Retry.MaxDelay = MaxRetryDelay;
             clientOptions.Retry.Mode = RetryMode.Exponential;
             clientOptions.AddPolicy(new UserAgentHeaderPolicy(), HttpPipelinePosition.PerCall);
+            clientOptions.Transport = new HttpClientTransport(new HttpClient()
+            {
+                Timeout = NetworkTimeout
+            });
 
             return clientOptions;
         }
+
+        /// <summary>
+        /// Disposes of this instance of <see cref="AzureAppConfigurationOptions"/> and any resources it holds.
+        /// </summary>
+        public void Dispose()
+        {
+            if (ClientOptions.Transport is HttpClientTransport transport)
+            {
+                transport.Dispose();
+            }
+        }
     }
 }

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

@@ -1221,6 +1221,13 @@ await ExecuteWithFailOverPolicyAsync<object>(clients, async (client) =>
 
         private bool IsFailOverable(AggregateException ex)
         {
+            TaskCanceledException tce = ex.InnerExceptions?.LastOrDefault(e => e is TaskCanceledException) as TaskCanceledException;
+
+            if (tce != null && tce.InnerException is TimeoutException)
+            {
+                return true;
+            }
+
             RequestFailedException rfe = ex.InnerExceptions?.LastOrDefault(e => e is RequestFailedException) as RequestFailedException;
 
             return rfe != null ? IsFailOverable(rfe) : false;