throttle CacheTable refresh

AsbCloudInfrastructure/Services/Cache/CacheTable.cs

@@ -14,6 +14,8 @@ namespace AsbCloudInfrastructure.Services.Cache
     {
         private const int semaphoreTimeout = 5_000;
         private static readonly SemaphoreSlim semaphore = new(1);
+        private static readonly TimeSpan minPeriodRefresh = TimeSpan.FromSeconds(3);
+
         private readonly DbContext context;
         private (DateTime refreshDate, IEnumerable entities) data;
         private readonly List<TEntity> cached;
@@ -26,7 +28,7 @@ namespace AsbCloudInfrastructure.Services.Cache
             dbSet = context.Set<TEntity>();
             cached = (List<TEntity>)data.entities;
             if (cached.Count == 0)
-                Refresh();
+                Refresh(false);
         }
 
         public TEntity this[int index] { get => cached.ElementAt(index); }
@@ -89,37 +91,45 @@ namespace AsbCloudInfrastructure.Services.Cache
             return true;
         }
 
-        private void InternalRefresh()
+        private void InternalRefresh(bool force)
         {
+            if (!force && (data.refreshDate + minPeriodRefresh >= DateTime.Now))
+                return;
+            
             cached.Clear();
             var entities = dbSet.AsNoTracking().ToList();
-            cached.AddRange(entities);
-            data.refreshDate = DateTime.Now;
-        }
-
-        private async Task InternalRefreshAsync(CancellationToken token = default)
-        {
-            cached.Clear();
-            var entities = await context.Set<TEntity>().AsNoTracking()
-                .ToListAsync(token).ConfigureAwait(false);
+            Trace.WriteLine($"CacheTable<{typeof(TEntity).Name}> refresh");
             cached.AddRange(entities);
             data.refreshDate = DateTime.Now;            
         }
 
-        public int Refresh()
+        private async Task InternalRefreshAsync(bool force, CancellationToken token = default)
+        {
+            if (!force && (data.refreshDate + minPeriodRefresh >= DateTime.Now))
+                return;
+
+            cached.Clear();
+            var entities = await context.Set<TEntity>().AsNoTracking()
+                .ToListAsync(token).ConfigureAwait(false);
+            Trace.WriteLine($"CacheTable<{typeof(TEntity).Name}> refresh");
+            cached.AddRange(entities);
+            data.refreshDate = DateTime.Now;            
+        }
+
+        public int Refresh(bool force)
         {
             Sync((wasFree) => {
                 if (wasFree)
-                    InternalRefresh();
+                    InternalRefresh(force);
                 });
             return cached.Count;
         }
 
-        public async Task<int> RefreshAsync(CancellationToken token = default)
+        public async Task<int> RefreshAsync(bool force, CancellationToken token = default)
         {
             await SyncAsync(async (wasFree, token) => {
                 if (wasFree)
-                    await InternalRefreshAsync(token).ConfigureAwait(false);
+                    await InternalRefreshAsync(force, token).ConfigureAwait(false);
             }, token).ConfigureAwait(false);
             return cached.Count;
         }
@@ -138,14 +148,14 @@ namespace AsbCloudInfrastructure.Services.Cache
                 if (result != default)
                     return;
 
-                InternalRefresh();                
+                InternalRefresh(true);                
                 result = cached.FirstOrDefault(predicate);
                 if (result != default)
                     return;
 
                 var entry = dbSet.Add(makeNew());
                 context.SaveChanges();
-                InternalRefresh();
+                InternalRefresh(true);
                 result = entry.Entity;                
             });
             return result;
@@ -157,7 +167,7 @@ namespace AsbCloudInfrastructure.Services.Cache
             if (result != default)
                 return result;
 
-            Refresh();
+            Refresh(false);
             return cached.FirstOrDefault();
         }
 
@@ -167,7 +177,7 @@ namespace AsbCloudInfrastructure.Services.Cache
             if (result != default)
                 return result;
 
-            await RefreshAsync(token);
+            await RefreshAsync(false, token);
             return cached.FirstOrDefault();            
         }
 
@@ -177,7 +187,7 @@ namespace AsbCloudInfrastructure.Services.Cache
             if (result != default)
                 return result;
 
-            Refresh();
+            Refresh(false);
             return cached.FirstOrDefault(predicate);
         }
 
@@ -187,7 +197,7 @@ namespace AsbCloudInfrastructure.Services.Cache
             if (result != default)
                 return result;
 
-            await RefreshAsync(token);
+            await RefreshAsync(false, token);
             return cached.FirstOrDefault(predicate);
         }
 
@@ -199,7 +209,7 @@ namespace AsbCloudInfrastructure.Services.Cache
             if (result.Any())
                 return result;
 
-            Refresh();
+            Refresh(false);
             result = (predicate != default)
                 ? cached.Where(predicate)
                 : cached;
@@ -218,7 +228,7 @@ namespace AsbCloudInfrastructure.Services.Cache
             if (result.Any())
                 return result;
 
-            await RefreshAsync(token);
+            await RefreshAsync(false, token);
             result = (predicate != default)
                 ? cached.Where(predicate)
                 : cached;
@@ -236,7 +246,7 @@ namespace AsbCloudInfrastructure.Services.Cache
                 else
                     dbSet.Add(entity);
                 context.SaveChanges();
-                InternalRefresh();
+                InternalRefresh(true);
             });                
         }
 
@@ -247,7 +257,7 @@ namespace AsbCloudInfrastructure.Services.Cache
                 else
                     dbSet.Add(entity);
                 await context.SaveChangesAsync(token).ConfigureAwait(false);
-                await InternalRefreshAsync(token).ConfigureAwait(false);
+                await InternalRefreshAsync(true, token).ConfigureAwait(false);
             }, token);
 
         public void Upsert(IEnumerable<TEntity> entities)
@@ -265,7 +275,7 @@ namespace AsbCloudInfrastructure.Services.Cache
                         dbSet.Add(entity);                 
                 }
                 context.SaveChanges();
-                InternalRefresh();
+                InternalRefresh(true);
             });
         }
 
@@ -284,7 +294,7 @@ namespace AsbCloudInfrastructure.Services.Cache
                         dbSet.Add(entity);
                 }
                 await context.SaveChangesAsync(token).ConfigureAwait(false);
-                await InternalRefreshAsync(token).ConfigureAwait(false);
+                await InternalRefreshAsync(true, token).ConfigureAwait(false);
             }, token);
         }
 
@@ -293,14 +303,14 @@ namespace AsbCloudInfrastructure.Services.Cache
             {
                 dbSet.RemoveRange(dbSet.Where(predicate));
                 context.SaveChanges();
-                InternalRefresh();
+                InternalRefresh(true);
             });
         
         public Task RemoveAsync(Func<TEntity, bool> predicate, CancellationToken token = default)
             => SyncAsync(async (wasFree, token) => {
                 dbSet.RemoveRange(dbSet.Where(predicate));
                 await context.SaveChangesAsync(token).ConfigureAwait(false);
-                await InternalRefreshAsync(token).ConfigureAwait(false);
+                await InternalRefreshAsync(true, token).ConfigureAwait(false);
             }, token);
 
         public TEntity Insert(TEntity entity)
@@ -310,7 +320,7 @@ namespace AsbCloudInfrastructure.Services.Cache
             {
                 var entry = dbSet.Add(entity);
                 context.SaveChanges();
-                InternalRefresh();
+                InternalRefresh(true);
                 result = entry.Entity;
             });
             return result;
@@ -323,7 +333,7 @@ namespace AsbCloudInfrastructure.Services.Cache
             {
                 var entry = dbSet.Add(entity);
                 await context.SaveChangesAsync(token).ConfigureAwait(false);
-                await InternalRefreshAsync(token).ConfigureAwait(false);
+                await InternalRefreshAsync(true, token).ConfigureAwait(false);
                 result = entry.Entity;
             }, token);
             return result;
@@ -335,7 +345,7 @@ namespace AsbCloudInfrastructure.Services.Cache
             Sync(_ => {
                 dbSet.AddRange(newEntities);
                 result = context.SaveChanges();
-                InternalRefresh();
+                InternalRefresh(true);
             });            
             return result;
         }
@@ -346,7 +356,7 @@ namespace AsbCloudInfrastructure.Services.Cache
             await SyncAsync(async (wasFree, token) => {
                 dbSet.AddRange(newEntities);
                 result = await context.SaveChangesAsync(token).ConfigureAwait(false);
-                await RefreshAsync(token).ConfigureAwait(false);
+                await InternalRefreshAsync(true, token).ConfigureAwait(false);
             }, token);
             return result;
         }