improve threading synchronization for date lookup cache

Data/Helpers/DataValueCache.cs

@@ -68,10 +68,15 @@ namespace Data.Helpers
 
             foreach (var id in ids)
             {
-                if (_cacheStates[key].ContainsKey(id))
+                var cacheInstance = _cacheStates[key];
+
+                lock (_cacheStates)
+                {
+                    if (cacheInstance.ContainsKey(id))
                     {
                         continue;
                     }
+                }
 
                 var state = new CacheState<TReturnType>
                 {
@@ -80,11 +85,13 @@ namespace Data.Helpers
                     ExpirationTime = expirationTime ?? TimeSpan.FromMinutes(DefaultExpireMinutes)
                 };
 
-                _cacheStates[key].Add(id, state);
+                lock (_cacheStates)
+                {
+                    cacheInstance.Add(id, state);
+                }
 
                 _autoRefresh = autoRefresh;
 
-
                 if (!_autoRefresh || expirationTime == TimeSpan.MaxValue)
                 {
                     return;
@@ -96,8 +103,8 @@ namespace Data.Helpers
             }
         }
 
-        public async Task<TReturnType> GetCacheItem(string keyName, CancellationToken cancellationToken = default) =>
+        public Task<TReturnType> GetCacheItem(string keyName, CancellationToken cancellationToken = default) =>
-            await GetCacheItem(keyName, null, cancellationToken);
+            GetCacheItem(keyName, null, cancellationToken);
 
         public async Task<TReturnType> GetCacheItem(string keyName, object id = null,
             CancellationToken cancellationToken = default)
@@ -107,7 +114,14 @@ namespace Data.Helpers
                 throw new ArgumentException("No cache found for key {key}", keyName);
             }
 
-            var state = id is null ? _cacheStates[keyName].Values.First() : _cacheStates[keyName][id];
+            var cacheInstance = _cacheStates[keyName];
+
+            CacheState<TReturnType> state;
+            
+            lock (_cacheStates)
+            {
+                state = id is null ? cacheInstance.Values.First() : _cacheStates[keyName][id];
+            }
 
             // when auto refresh is off we want to check the expiration and value
             // when auto refresh is on, we want to only check the value, because it'll be refreshed automatically

Data/Helpers/LookupCache.cs

@@ -8,14 +8,14 @@ using System.Threading;
 using System.Threading.Tasks;
 using ILogger = Microsoft.Extensions.Logging.ILogger;
 
-namespace Data.Helpers
+namespace Data.Helpers;
+
+public class LookupCache<T> : ILookupCache<T> where T : class, IUniqueId
 {
-    public class LookupCache<T> : ILookupCache<T> where T : class, IUniqueId
-    {
     private readonly ILogger _logger;
     private readonly IDatabaseContextFactory _contextFactory;
     private Dictionary<long, T> _cachedItems;
-        private readonly SemaphoreSlim _onOperation = new SemaphoreSlim(1, 1);
+    private readonly SemaphoreSlim _onOperation = new(1, 1);
 
     public LookupCache(ILogger<LookupCache<T>> logger, IDatabaseContextFactory contextFactory)
     {
@@ -35,7 +35,7 @@ namespace Data.Helpers
 
         if (existingItem != null)
         {
-                _logger.LogDebug("Cached item already added for {type} {id} {value}", typeof(T).Name, item.Id,
+            _logger.LogDebug("Cached item already added for {Type} {Id} {Value}", typeof(T).Name, item.Id,
                 item.Value);
             _onOperation.Release();
             return existingItem;
@@ -43,7 +43,7 @@ namespace Data.Helpers
 
         try
         {
-                _logger.LogDebug("Adding new {type} with {id} {value}", typeof(T).Name, item.Id, item.Value);
+            _logger.LogDebug("Adding new {Type} with {Id} {Value}", typeof(T).Name, item.Id, item.Value);
             await using var context = _contextFactory.CreateContext();
             context.Set<T>().Add(item);
             await context.SaveChangesAsync();
@@ -52,7 +52,7 @@ namespace Data.Helpers
         }
         catch (Exception ex)
         {
-                _logger.LogError(ex, "Could not add item to cache for {type}", typeof(T).Name);
+            _logger.LogError(ex, "Could not add item to cache for {Type}", typeof(T).Name);
             throw new Exception("Could not add item to cache");
         }
         finally
@@ -66,22 +66,12 @@ namespace Data.Helpers
 
     public async Task<T> FirstAsync(Func<T, bool> query)
     {
-            await _onOperation.WaitAsync();
-
         try
         {
+            await _onOperation.WaitAsync();
             var cachedResult = _cachedItems.Values.Where(query);
-
-                if (cachedResult.Any())
-                {
             return cachedResult.FirstOrDefault();
         }
-            }
-
-            catch
-            {
-            }
-
         finally
         {
             if (_onOperation.CurrentCount == 0)
@@ -89,8 +79,6 @@ namespace Data.Helpers
                 _onOperation.Release(1);
             }
         }
-
-            return null;
     }
 
     public IEnumerable<T> GetAll()
@@ -107,8 +95,7 @@ namespace Data.Helpers
         }
         catch (Exception ex)
         {
-                _logger.LogError(ex, "Could not initialize caching for {cacheType}", typeof(T).Name);
+            _logger.LogError(ex, "Could not initialize caching for {CacheType}", typeof(T).Name);
-            }
         }
     }
 }