Add BootstrapRefreshInterval (#2052)

Add a new timer with exponential backoff for failing to fetch metadata at bootstrap til we get the first config
AzureAD · Apr 13, 2023 · 90da399 · 90da399
1 parent 2eb488a
commit 90da399
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Showing 3 changed files with 73 additions and 7 deletions.
diff --git a/src/Microsoft.IdentityModel.Protocols/Configuration/ConfigurationManager.cs b/src/Microsoft.IdentityModel.Protocols/Configuration/ConfigurationManager.cs
@@ -29,11 +29,12 @@ public class ConfigurationManager<T> : BaseConfigurationManager, IConfigurationM
         private readonly IConfigurationValidator<T> _configValidator;
         private T _currentConfiguration;
         private Exception _fetchMetadataFailure;
+        private TimeSpan _bootstrapRefreshInterval = TimeSpan.FromSeconds(1);
 
-        /// <summary>
-        /// Static initializer for a new object. Static initializers run before the first instance of the type is created.
-        /// </summary>
-        static ConfigurationManager()
+    /// <summary>
+    /// Static initializer for a new object. Static initializers run before the first instance of the type is created.
+    /// </summary>
+    static ConfigurationManager()
         {               
         }
 
@@ -182,15 +183,33 @@ public async Task<T> GetConfigurationAsync(CancellationToken cancel)
                     catch (Exception ex)
                     {
                         _fetchMetadataFailure = ex;
-                        _syncAfter = DateTimeUtil.Add(now.UtcDateTime, AutomaticRefreshInterval < RefreshInterval ? AutomaticRefreshInterval : RefreshInterval);
+
                         if (_currentConfiguration == null) // Throw an exception if there's no configuration to return.
+                        {
+                            if (_bootstrapRefreshInterval < RefreshInterval)
+                            {
+                                // Adopt exponential backoff for bootstrap refresh interval with a decorrelated jitter if it is not longer than the refresh interval.
+                                TimeSpan _bootstrapRefreshIntervalWithJitter = TimeSpan.FromSeconds(new Random().Next((int)_bootstrapRefreshInterval.TotalSeconds));
+                                _bootstrapRefreshInterval += _bootstrapRefreshInterval;
+                                _syncAfter = DateTimeUtil.Add(now.UtcDateTime, _bootstrapRefreshIntervalWithJitter);
+                            }
+                            else
+                            {
+                                _syncAfter = DateTimeUtil.Add(now.UtcDateTime, AutomaticRefreshInterval < RefreshInterval ? AutomaticRefreshInterval : RefreshInterval);
+                            }
+
                             throw LogHelper.LogExceptionMessage(
                                 new InvalidOperationException(
-                                    LogHelper.FormatInvariant(LogMessages.IDX20803, LogHelper.MarkAsNonPII(MetadataAddress ?? "null"), LogHelper.MarkAsNonPII(ex)), ex));
+                                    LogHelper.FormatInvariant(LogMessages.IDX20803, LogHelper.MarkAsNonPII(MetadataAddress ?? "null"), LogHelper.MarkAsNonPII(_syncAfter), LogHelper.MarkAsNonPII(ex)), ex));
+                        } 
                         else
+                        {
+                            _syncAfter = DateTimeUtil.Add(now.UtcDateTime, AutomaticRefreshInterval < RefreshInterval ? AutomaticRefreshInterval : RefreshInterval);
+
                             LogHelper.LogExceptionMessage(
                                 new InvalidOperationException(
                                     LogHelper.FormatInvariant(LogMessages.IDX20806, LogHelper.MarkAsNonPII(MetadataAddress ?? "null"), LogHelper.MarkAsNonPII(ex)), ex));
+                        }
                     }
                 }
 

diff --git a/src/Microsoft.IdentityModel.Protocols/LogMessages.cs b/src/Microsoft.IdentityModel.Protocols/LogMessages.cs
@@ -21,7 +21,7 @@ internal static class LogMessages
         internal const string IDX20108 = "IDX20108: The address specified '{0}' is not valid as per HTTPS scheme. Please specify an https address for security reasons. If you want to test with http address, set the RequireHttps property  on IDocumentRetriever to false.";
 
         // configuration retrieval errors
-        internal const string IDX20803 = "IDX20803: Unable to obtain configuration from: '{0}'. Exception: '{1}.";
+        internal const string IDX20803 = "IDX20803: Unable to obtain configuration from: '{0}'. Will retry at '{1}'. Exception: '{2}'.";
         internal const string IDX20804 = "IDX20804: Unable to retrieve document from: '{0}'.";
         internal const string IDX20805 = "IDX20805: Obtaining information from metadata endpoint: '{0}'.";
         internal const string IDX20806 = "IDX20806: Unable to obtain an updated configuration from: '{0}'. Returning the current configuration. Exception: '{1}.";

diff --git a/test/Microsoft.IdentityModel.Protocols.OpenIdConnect.Tests/ConfigurationManagerTests.cs b/test/Microsoft.IdentityModel.Protocols.OpenIdConnect.Tests/ConfigurationManagerTests.cs
@@ -136,6 +136,53 @@ public void FetchMetadataFailureTest()
             TestUtilities.AssertFailIfErrors(context);
         }
 
+        [Fact]
+        public void BootstrapRefreshIntervalTest()
+        {
+            var context = new CompareContext($"{this}.BootstrapRefreshIntervalTest");
+
+            var documentRetriever = new HttpDocumentRetriever(HttpResponseMessageUtils.SetupHttpClientThatReturns("OpenIdConnectMetadata.json", HttpStatusCode.NotFound));
+            var configManager = new ConfigurationManager<OpenIdConnectConfiguration>("OpenIdConnectMetadata.json", new OpenIdConnectConfigurationRetriever(), documentRetriever) { RefreshInterval = TimeSpan.FromSeconds(2) };
+
+            // First time to fetch metadata.
+            try
+            {
+                var configuration = configManager.GetConfigurationAsync().Result;
+            }
+            catch (Exception firstFetchMetadataFailure)
+            {
+                // Refresh interval is BootstrapRefreshInterval
+                var syncAfter = configManager.GetType().GetField("_syncAfter", BindingFlags.NonPublic | BindingFlags.Instance).GetValue(configManager);
+                if ((DateTimeOffset)syncAfter > DateTime.UtcNow + TimeSpan.FromSeconds(2))
+                    context.AddDiff($"Expected the refresh interval is longer than 2 seconds.");
+
+                if (firstFetchMetadataFailure.InnerException == null)
+                    context.AddDiff($"Expected exception to contain inner exception for fetch metadata failure.");
+
+                // Fetch metadata again during refresh interval, the exception should be same from above.
+                try
+                {
+                    configManager.RequestRefresh();
+                    var configuration = configManager.GetConfigurationAsync().Result;
+                }
+                catch (Exception secondFetchMetadataFailure)
+                {
+                    if (secondFetchMetadataFailure.InnerException == null)
+                        context.AddDiff($"Expected exception to contain inner exception for fetch metadata failure.");
+
+                    syncAfter = configManager.GetType().GetField("_syncAfter", BindingFlags.NonPublic | BindingFlags.Instance).GetValue(configManager);
+
+                    // Refresh interval is RefreshInterval
+                    if ((DateTimeOffset)syncAfter > DateTime.UtcNow + configManager.RefreshInterval)
+                        context.AddDiff($"Expected the refresh interval is longer than 2 seconds.");
+
+                    IdentityComparer.AreEqual(firstFetchMetadataFailure, secondFetchMetadataFailure, context);
+                }
+            }
+
+            TestUtilities.AssertFailIfErrors(context);
+        }
+
         [Fact]
         public void GetSets()
         {