Expose access token cache count

src/client/Microsoft.Identity.Client/AuthenticationResultMetadata.cs

@@ -97,5 +97,10 @@ public AuthenticationResultMetadata(TokenSource tokenSource)
         /// See https://aka.ms/msal-net-logging for more details about logging.
         /// </remarks>
         public string Telemetry { get; set; }
+
+        /// <summary>
+        /// The number of access tokens in the cache.       
+        /// </summary>
+        public int CachedAccessTokenCount { get; set; }
     }
 }

src/client/Microsoft.Identity.Client/Cache/CacheSessionManager.cs

@@ -48,9 +48,11 @@ public async Task<MsalAccessTokenCacheItem> FindAccessTokenAsync()
             return await TokenCacheInternal.FindAccessTokenAsync(_requestParams).ConfigureAwait(false);
         }
 
-        public Task<Tuple<MsalAccessTokenCacheItem, MsalIdTokenCacheItem, Account>> SaveTokenResponseAsync(MsalTokenResponse tokenResponse)
+        public async Task<Tuple<MsalAccessTokenCacheItem, MsalIdTokenCacheItem, Account>> SaveTokenResponseAsync(MsalTokenResponse tokenResponse)
         {
-            return TokenCacheInternal.SaveTokenResponseAsync(_requestParams, tokenResponse);
+            var result = await TokenCacheInternal.SaveTokenResponseAsync(_requestParams, tokenResponse).ConfigureAwait(false);
+            RequestContext.ApiEvent.CachedAccessTokenCount = TokenCacheInternal.Accessor.EntryCount;
+            return result;
         }
 
         public async Task<Account> GetAccountAssociatedWithAccessTokenAsync(MsalAccessTokenCacheItem msalAccessTokenCacheItem)
@@ -181,6 +183,8 @@ private async Task RefreshCacheForReadOperationsAsync()
             {
                 RequestContext.ApiEvent.CacheLevel = CacheLevel.L1Cache;
             }
+
+            RequestContext.ApiEvent.CachedAccessTokenCount = TokenCacheInternal.Accessor.EntryCount;
         }
     }
 }

src/client/Microsoft.Identity.Client/Cache/ITokenCacheAccessor.cs

@@ -10,6 +10,8 @@ namespace Microsoft.Identity.Client.Cache
 {
     internal interface ITokenCacheAccessor
     {
+        int EntryCount { get; }
+
         void SaveAccessToken(MsalAccessTokenCacheItem item);
 
         void SaveRefreshToken(MsalRefreshTokenCacheItem item);

src/client/Microsoft.Identity.Client/Internal/Requests/RequestBase.cs

@@ -223,6 +223,7 @@ private void UpdateTelemetry(long elapsedMilliseconds, ApiEvent apiEvent, Authen
             authenticationResult.AuthenticationResultMetadata.CacheLevel = GetCacheLevel(authenticationResult);
             authenticationResult.AuthenticationResultMetadata.Telemetry = apiEvent.MsalRuntimeTelemetry;
             authenticationResult.AuthenticationResultMetadata.RegionDetails = CreateRegionDetails(apiEvent);
+            authenticationResult.AuthenticationResultMetadata.CachedAccessTokenCount = apiEvent.CachedAccessTokenCount;
 
             Metrics.IncrementTotalDurationInMs(authenticationResult.AuthenticationResultMetadata.DurationTotalInMs);
         }

src/client/Microsoft.Identity.Client/Platforms/Android/AndroidTokenCacheAccessor.cs

@@ -161,6 +161,8 @@ public List<MsalAccountCacheItem> GetAllAccounts(string optionalPartitionKey = n
         }
         #endregion
 
+        public int EntryCount { get; } = 0; // not implemented for Android
+
         public MsalAccountCacheItem GetAccount(MsalAccountCacheItem accountCacheItem)
         {
             return MsalAccountCacheItem.FromJsonString(_accountSharedPreference.GetString(accountCacheItem.CacheKey, null));

src/client/Microsoft.Identity.Client/Platforms/iOS/iOSTokenCacheAccessor.cs

@@ -167,7 +167,10 @@ public List<MsalAccountCacheItem> GetAllAccounts(string optionalPartitionKey = n
                 .Select(x => MsalAccountCacheItem.FromJsonString(x))
                 .ToList();
         }
-#endregion
+        #endregion
+
+        public int EntryCount { get; } = 0; // not implemented for iOS
+
 
         internal SecStatusCode TryGetBrokerApplicationToken(string clientId, out string appToken)
         {

src/client/Microsoft.Identity.Client/PlatformsCommon/Shared/InMemoryPartitionedAppTokenCacheAccessor.cs

@@ -5,6 +5,7 @@
 using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Linq;
+using System.Threading;
 using Microsoft.Identity.Client.Cache;
 using Microsoft.Identity.Client.Cache.Items;
 using Microsoft.Identity.Client.Core;
@@ -34,6 +35,11 @@ internal class InMemoryPartitionedAppTokenCacheAccessor : ITokenCacheAccessor
         protected readonly ILoggerAdapter _logger;
         private readonly CacheOptions _tokenCacheAccessorOptions;
 
+        private int _entryCount = 0;
+        private static int s_entryCount = 0;
+
+        public int EntryCount => GetEntryCountRef();
+
         public InMemoryPartitionedAppTokenCacheAccessor(
             ILoggerAdapter logger,
             CacheOptions tokenCacheAccessorOptions)
@@ -59,9 +65,18 @@ public void SaveAccessToken(MsalAccessTokenCacheItem item)
             string itemKey = item.CacheKey;
             string partitionKey = CacheKeyFactory.GetAppTokenCacheItemKey(item.ClientId, item.TenantId, item.KeyId, item.AdditionalCacheKeyComponents);
 
-            // if a conflict occurs, pick the latest value
-            AccessTokenCacheDictionary
-                .GetOrAdd(partitionKey, new ConcurrentDictionary<string, MsalAccessTokenCacheItem>())[itemKey] = item;
+            var partition = AccessTokenCacheDictionary.GetOrAdd(partitionKey, _ => new ConcurrentDictionary<string, MsalAccessTokenCacheItem>());
+            bool added = partition.TryAdd(itemKey, item);
+
+            // only increment the entry count if the item was added, not updated
+            if (added)
+            {
+                Interlocked.Increment(ref GetEntryCountRef());
+            }
+            else
+            {
+                partition[itemKey] = item;
+            }
         }
 
         /// <summary>
@@ -129,12 +144,19 @@ public void DeleteAccessToken(MsalAccessTokenCacheItem item)
         {
             var partitionKey = CacheKeyFactory.GetAppTokenCacheItemKey(item.ClientId, item.TenantId, item.KeyId);
 
-            AccessTokenCacheDictionary.TryGetValue(partitionKey, out var partition);
-            if (partition == null || !partition.TryRemove(item.CacheKey, out _))
+            if (AccessTokenCacheDictionary.TryGetValue(partitionKey, out var partition))
             {
-                _logger.InfoPii(
-                    () => $"[Internal cache] Cannot delete access token because it was not found in the cache. Key {item.CacheKey}.",
-                    () => "[Internal cache] Cannot delete access token because it was not found in the cache.");
+                bool removed = partition.TryRemove(item.CacheKey, out _);
+                if (removed)
+                {
+                    Interlocked.Decrement(ref GetEntryCountRef());
+                }
+                else
+                {
+                    _logger.InfoPii(
+                        () => $"[Internal cache] Cannot delete access token because it was not found in the cache. Key {item.CacheKey}.",
+                        () => "[Internal cache] Cannot delete access token because it was not found in the cache.");
+                }
             }
         }
 
@@ -219,6 +241,7 @@ public virtual void Clear(ILoggerAdapter requestlogger = null)
         {
             var logger = requestlogger ?? _logger;
             AccessTokenCacheDictionary.Clear();
+            Interlocked.Exchange(ref GetEntryCountRef(), 0);
             logger.Always("[Internal cache] Clearing app token cache accessor.");
             // app metadata isn't removable
         }
@@ -227,5 +250,11 @@ public virtual bool HasAccessOrRefreshTokens()
         {
             return AccessTokenCacheDictionary.Any(partition => partition.Value.Any(token => !token.Value.IsExpiredWithBuffer()));
         }
+
+        private ref int GetEntryCountRef()
+        {
+            return ref _tokenCacheAccessorOptions.UseSharedCache ? ref s_entryCount : ref _entryCount;
+        }
+
     }
 }

src/client/Microsoft.Identity.Client/PlatformsCommon/Shared/InMemoryPartitionedUserTokenCacheAccessor.cs

@@ -41,9 +41,15 @@ internal class InMemoryPartitionedUserTokenCacheAccessor : ITokenCacheAccessor
         private static readonly ConcurrentDictionary<string, MsalAppMetadataCacheItem> s_appMetadataDictionary =
             new ConcurrentDictionary<string, MsalAppMetadataCacheItem>();
 
+        private static int s_entryCount = 0;
+
         protected readonly ILoggerAdapter _logger;
         private readonly CacheOptions _tokenCacheAccessorOptions;
 
+        private int _entryCount = 0;
+
+        public int EntryCount => GetEntryCountRef();
+
         public InMemoryPartitionedUserTokenCacheAccessor(ILoggerAdapter logger, CacheOptions tokenCacheAccessorOptions)
         {
             _logger = logger ?? throw new ArgumentNullException(nameof(logger));
@@ -73,8 +79,17 @@ public void SaveAccessToken(MsalAccessTokenCacheItem item)
             string itemKey = item.CacheKey;
             string partitionKey = CacheKeyFactory.GetKeyFromCachedItem(item);
 
-            AccessTokenCacheDictionary
-                .GetOrAdd(partitionKey, new ConcurrentDictionary<string, MsalAccessTokenCacheItem>())[itemKey] = item; // if a conflict occurs, pick the latest value
+            var partition = AccessTokenCacheDictionary.GetOrAdd(partitionKey, _ => new ConcurrentDictionary<string, MsalAccessTokenCacheItem>());
+            bool added = partition.TryAdd(itemKey, item);
+            // only increment the entry count if this is a new item
+            if (added)
+            {
+                System.Threading.Interlocked.Increment(ref GetEntryCountRef());
+            }
+            else
+            {
+                partition[itemKey] = item;
+            }
         }
 
         public void SaveRefreshToken(MsalRefreshTokenCacheItem item)
@@ -151,12 +166,19 @@ public void DeleteAccessToken(MsalAccessTokenCacheItem item)
         {
             string partitionKey = CacheKeyFactory.GetKeyFromCachedItem(item);
 
-            AccessTokenCacheDictionary.TryGetValue(partitionKey, out var partition);
-            if (partition == null || !partition.TryRemove(item.CacheKey, out _))
+            if (AccessTokenCacheDictionary.TryGetValue(partitionKey, out var partition))
             {
-                _logger.InfoPii(
-                    () => $"[Internal cache] Cannot delete access token because it was not found in the cache. Key {item.CacheKey}.",
-                    () => "[Internal cache] Cannot delete access token because it was not found in the cache.");
+                bool removed = partition.TryRemove(item.CacheKey, out _);                
+                if (removed)
+                {
+                    System.Threading.Interlocked.Decrement(ref GetEntryCountRef());
+                }
+                else
+                {
+                    _logger.InfoPii(
+                        () => $"[Internal cache] Cannot delete access token because it was not found in the cache. Key {item.CacheKey}.",
+                        () => "[Internal cache] Cannot delete access token because it was not found in the cache.");
+                }
             }
         }
 
@@ -246,7 +268,7 @@ public virtual List<MsalRefreshTokenCacheItem> GetAllRefreshTokens(string partit
                     if (RefreshTokenCacheDictionary.Count == 1 && result.Count == 0)
                     {
                         logger.VerbosePii(
-                            () => $"[Internal cache] 0 RTs and 1 partition. Partition in cache is {RefreshTokenCacheDictionary.Keys.First()}", 
+                            () => $"[Internal cache] 0 RTs and 1 partition. Partition in cache is {RefreshTokenCacheDictionary.Keys.First()}",
                             () => "[Internal cache] 0 RTs and 1 partition] 0 RTs and 1 partition.");
                     }
                 }
@@ -290,7 +312,7 @@ public virtual List<MsalAccountCacheItem> GetAllAccounts(string partitionKey = n
             {
                 AccountCacheDictionary.TryGetValue(partitionKey, out ConcurrentDictionary<string, MsalAccountCacheItem> partition);
                 result = partition?.Select(kv => kv.Value)?.ToList() ?? CollectionHelpers.GetEmptyList<MsalAccountCacheItem>();
-                
+
                 if (logger.IsLoggingEnabled(LogLevel.Verbose))
                 {
                     logger.Verbose(() => $"[Internal cache] GetAllAccounts (with partition - exists? {partition != null}) found {result.Count} accounts.");
@@ -327,6 +349,8 @@ public virtual void Clear(ILoggerAdapter requestlogger = null)
             IdTokenCacheDictionary.Clear();
             AccountCacheDictionary.Clear();
             // app metadata isn't removable
+            System.Threading.Interlocked.Exchange(ref GetEntryCountRef(), 0);
+
         }
 
         /// WARNING: this API is slow as it loads all tokens, not just from 1 partition. 
@@ -336,5 +360,10 @@ public virtual bool HasAccessOrRefreshTokens()
             return RefreshTokenCacheDictionary.Any(partition => partition.Value.Count > 0) ||
                     AccessTokenCacheDictionary.Any(partition => partition.Value.Any(token => !token.Value.IsExpiredWithBuffer()));
         }
+
+        private ref int GetEntryCountRef()
+        {
+            return ref _tokenCacheAccessorOptions.UseSharedCache ? ref s_entryCount : ref _entryCount;
+        }
     }
 }

src/client/Microsoft.Identity.Client/PublicApi/net462/PublicAPI.Unshipped.txt

@@ -5,3 +5,5 @@ Microsoft.Identity.Client.Utils.MacMainThreadScheduler.IsRunning() -> bool
 Microsoft.Identity.Client.Utils.MacMainThreadScheduler.Stop() -> void
 Microsoft.Identity.Client.Utils.MacMainThreadScheduler.RunOnMainThreadAsync(System.Func<System.Threading.Tasks.Task> asyncAction) -> System.Threading.Tasks.Task
 Microsoft.Identity.Client.Utils.MacMainThreadScheduler.StartMessageLoop() -> void
+Microsoft.Identity.Client.AuthenticationResultMetadata.CachedAccessTokenCount.get -> int
+Microsoft.Identity.Client.AuthenticationResultMetadata.CachedAccessTokenCount.set -> void

src/client/Microsoft.Identity.Client/PublicApi/net472/PublicAPI.Unshipped.txt

@@ -5,3 +5,5 @@ Microsoft.Identity.Client.Utils.MacMainThreadScheduler.IsRunning() -> bool
 Microsoft.Identity.Client.Utils.MacMainThreadScheduler.Stop() -> void
 Microsoft.Identity.Client.Utils.MacMainThreadScheduler.RunOnMainThreadAsync(System.Func<System.Threading.Tasks.Task> asyncAction) -> System.Threading.Tasks.Task
 Microsoft.Identity.Client.Utils.MacMainThreadScheduler.StartMessageLoop() -> void
+Microsoft.Identity.Client.AuthenticationResultMetadata.CachedAccessTokenCount.get -> int
+Microsoft.Identity.Client.AuthenticationResultMetadata.CachedAccessTokenCount.set -> void

src/client/Microsoft.Identity.Client/PublicApi/net8.0-android/PublicAPI.Unshipped.txt

@@ -5,3 +5,5 @@ Microsoft.Identity.Client.Utils.MacMainThreadScheduler.IsRunning() -> bool
 Microsoft.Identity.Client.Utils.MacMainThreadScheduler.Stop() -> void
 Microsoft.Identity.Client.Utils.MacMainThreadScheduler.RunOnMainThreadAsync(System.Func<System.Threading.Tasks.Task> asyncAction) -> System.Threading.Tasks.Task
 Microsoft.Identity.Client.Utils.MacMainThreadScheduler.StartMessageLoop() -> void
+Microsoft.Identity.Client.AuthenticationResultMetadata.CachedAccessTokenCount.get -> int
+Microsoft.Identity.Client.AuthenticationResultMetadata.CachedAccessTokenCount.set -> void

src/client/Microsoft.Identity.Client/PublicApi/net8.0-ios/PublicAPI.Unshipped.txt

@@ -5,3 +5,5 @@ Microsoft.Identity.Client.Utils.MacMainThreadScheduler.IsRunning() -> bool
 Microsoft.Identity.Client.Utils.MacMainThreadScheduler.Stop() -> void
 Microsoft.Identity.Client.Utils.MacMainThreadScheduler.RunOnMainThreadAsync(System.Func<System.Threading.Tasks.Task> asyncAction) -> System.Threading.Tasks.Task
 Microsoft.Identity.Client.Utils.MacMainThreadScheduler.StartMessageLoop() -> void
+Microsoft.Identity.Client.AuthenticationResultMetadata.CachedAccessTokenCount.get -> int
+Microsoft.Identity.Client.AuthenticationResultMetadata.CachedAccessTokenCount.set -> void

src/client/Microsoft.Identity.Client/PublicApi/net8.0/PublicAPI.Unshipped.txt

@@ -5,3 +5,5 @@ Microsoft.Identity.Client.Utils.MacMainThreadScheduler.IsRunning() -> bool
 Microsoft.Identity.Client.Utils.MacMainThreadScheduler.Stop() -> void
 Microsoft.Identity.Client.Utils.MacMainThreadScheduler.RunOnMainThreadAsync(System.Func<System.Threading.Tasks.Task> asyncAction) -> System.Threading.Tasks.Task
 Microsoft.Identity.Client.Utils.MacMainThreadScheduler.StartMessageLoop() -> void
+Microsoft.Identity.Client.AuthenticationResultMetadata.CachedAccessTokenCount.get -> int
+Microsoft.Identity.Client.AuthenticationResultMetadata.CachedAccessTokenCount.set -> void

src/client/Microsoft.Identity.Client/PublicApi/netstandard2.0/PublicAPI.Unshipped.txt

@@ -5,3 +5,5 @@ Microsoft.Identity.Client.Utils.MacMainThreadScheduler.IsRunning() -> bool
 Microsoft.Identity.Client.Utils.MacMainThreadScheduler.Stop() -> void
 Microsoft.Identity.Client.Utils.MacMainThreadScheduler.RunOnMainThreadAsync(System.Func<System.Threading.Tasks.Task> asyncAction) -> System.Threading.Tasks.Task
 Microsoft.Identity.Client.Utils.MacMainThreadScheduler.StartMessageLoop() -> void
+Microsoft.Identity.Client.AuthenticationResultMetadata.CachedAccessTokenCount.get -> int
+Microsoft.Identity.Client.AuthenticationResultMetadata.CachedAccessTokenCount.set -> void

src/client/Microsoft.Identity.Client/TelemetryCore/Internal/Events/ApiEvent.cs

@@ -62,6 +62,8 @@ public string ApiIdString
 
         public string ApiErrorCode { get; set; }
 
+        public int CachedAccessTokenCount { get; set; }
+
         #region Region
         public string RegionUsed { get; set; }
 

tests/Microsoft.Identity.Test.Performance/AcquireTokenForClientCacheTests.cs

@@ -46,7 +46,6 @@ public class AcquireTokenForClientCacheTests
 
         [ParamsAllValues]
         public bool EnableCacheSerialization { get; set; }
-
         //[Params(false)]
         public bool UseMicrosoftIdentityWebCache { get; set; }