Reduce Redis EXPIRE calls using CustomRedisSessionStoreCustom redis session store

dotnet/src/dotnetcore/GxNetCoreStartup/SessionHelper.cs

@@ -1,25 +1,23 @@
-using Microsoft.AspNetCore.Http;
-using Microsoft.Extensions.Caching.Distributed;
-using Microsoft.Extensions.Caching.StackExchangeRedis;
+using System;
 using System.Collections.Concurrent;
-using System.Threading.Tasks;
+using System.Linq;
 using System.Threading;
-using System;
+using System.Threading.Tasks;
 using GeneXus.Services;
-using System.Linq;
+using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.Caching.Distributed;
+using StackExchange.Redis;
 
 namespace GeneXus.Application
 {
 	public class TenantRedisCache : IDistributedCache
 	{
 		private readonly IHttpContextAccessor _httpContextAccessor;
-		private readonly IServiceProvider _serviceProvider;
-		private readonly ConcurrentDictionary<string, RedisCache> _redisCaches = new();
+		private readonly ConcurrentDictionary<string, IDistributedCache> _redisCaches = new();
 
-		public TenantRedisCache(IHttpContextAccessor httpContextAccessor, IServiceProvider serviceProvider)
+		public TenantRedisCache(IHttpContextAccessor httpContextAccessor)
 		{
 			_httpContextAccessor = httpContextAccessor;
-			_serviceProvider = serviceProvider;
 		}
 
 		private IDistributedCache GetTenantCache()
@@ -29,12 +27,7 @@ private IDistributedCache GetTenantCache()
 			return _redisCaches.GetOrAdd(tenantId, id =>
 			{
 				ISessionService sessionService = GXSessionServiceFactory.GetProvider();
-				var options = new RedisCacheOptions
-				{
-					Configuration = sessionService.ConnectionString,
-					InstanceName = $"{id}:"
-				};
-				return new RedisCache(options);
+				return new CustomRedisSessionStore(sessionService.ConnectionString, TimeSpan.FromMinutes(sessionService.SessionTimeout), id);
 			});
 		}
 
@@ -48,6 +41,80 @@ private IDistributedCache GetTenantCache()
 		public Task SetAsync(string key, byte[] value, DistributedCacheEntryOptions options, CancellationToken token = default) => GetTenantCache().SetAsync(key, value, options, token);
 	}
 
+	public class CustomRedisSessionStore : IDistributedCache
+	{
+		private readonly IDatabase _db;
+		private readonly TimeSpan _idleTimeout;
+		private readonly TimeSpan _refreshThreshold;
+		private readonly string _instanceName;
+
+		public CustomRedisSessionStore(string connectionString, TimeSpan idleTimeout, string instanceName)
+		{
+			var mux = ConnectionMultiplexer.Connect(connectionString);
+			_db = mux.GetDatabase();
+			_idleTimeout = idleTimeout;
+			_refreshThreshold = TimeSpan.FromTicks((long)(idleTimeout.Ticks * 0.2));
+			_instanceName = instanceName ?? string.Empty;
+		}
+
+		private string FormatKey(string key) => string.IsNullOrEmpty(_instanceName) ? key : $"{_instanceName}:{key}";
+
+		public byte[] Get(string key) => _db.StringGet(FormatKey(key));
+
+		public async Task<byte[]> GetAsync(string key, CancellationToken token = default)
+		{
+			string redisKey = FormatKey(key);
+			var value = await _db.StringGetAsync(redisKey);
+
+			await RefreshKeyIfNeededAsync(redisKey);
+
+			return value;
+		}
+
+		public void Refresh(string key)
+		{
+			string redisKey = FormatKey(key);
+
+			var ttl = _db.KeyTimeToLive(redisKey);
+
+			if (ShouldRefreshKey(ttl))
+			{
+				_db.KeyExpire(redisKey, _idleTimeout);
+			}
+		}
+		private bool ShouldRefreshKey(TimeSpan? ttl)
+		{
+			return ttl.HasValue && ttl.Value < _refreshThreshold;
+		}
+		public async Task RefreshAsync(string key, CancellationToken token = default)
+		{
+			string redisKey = FormatKey(key);
+			await RefreshKeyIfNeededAsync(redisKey);
+		}
+		private async Task RefreshKeyIfNeededAsync(string redisKey)
+		{
+			var ttl = await _db.KeyTimeToLiveAsync(redisKey);
+
+			if (ShouldRefreshKey(ttl))
+			{
+				_ = _db.KeyExpireAsync(redisKey, _idleTimeout);
+			}
+		}
+		public void Remove(string key) => _db.KeyDelete(FormatKey(key));
+
+		public Task RemoveAsync(string key, CancellationToken token = default)
+			=> _db.KeyDeleteAsync(FormatKey(key));
+
+		public void Set(string key, byte[] value, DistributedCacheEntryOptions options)
+		{
+			_db.StringSet(FormatKey(key), value, _idleTimeout);
+		}
+
+		public Task SetAsync(string key, byte[] value, DistributedCacheEntryOptions options, CancellationToken token = default)
+		{
+			return _db.StringSetAsync(FormatKey(key), value, _idleTimeout);
+		}
+	}
 
 	public class TenantMiddleware
 	{

dotnet/src/dotnetcore/GxNetCoreStartup/Startup.cs

@@ -468,12 +468,11 @@ private void ConfigureSessionService(IServiceCollection services, ISessionServic
 				}
 				else
 				{
-					services.AddStackExchangeRedisCache(options =>
-					{
-						GXLogging.Info(log, $"Using Redis for Distributed session, ConnectionString:{sessionService.ConnectionString}, InstanceName: {sessionService.InstanceName}");
-						options.Configuration = sessionService.ConnectionString;
-						options.InstanceName = sessionService.InstanceName;
-					});
+					GXLogging.Info(log, $"Using Redis for Distributed session, ConnectionString:{sessionService.ConnectionString}, InstanceName: {sessionService.InstanceName}");
+
+					services.AddSingleton<IDistributedCache>(sp =>
+						new CustomRedisSessionStore(sessionService.ConnectionString, TimeSpan.FromMinutes(Preferences.SessionTimeout), sessionService.InstanceName));
+
 					services.AddDataProtection().PersistKeysToStackExchangeRedis(ConnectionMultiplexer.Connect(sessionService.ConnectionString), DATA_PROTECTION_KEYS).SetApplicationName(sessionService.InstanceName);
 				}
 			}