magman/MagMan.Core/Services/BaseServ.cs

using NLog;
using StackExchange.Redis;
using Microsoft.Extensions.Configuration;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace MagMan.Core.Services
{
    /// <summary>
    /// Classe di partenza x costruzione servizi di accesso dati + cache
    /// </summary>
    public class BaseServ
    {
        #region Public Methods

        /// <summary>
        /// Refresh globale cache redis
        /// </summary>
        /// <returns></returns>
        public async Task<bool> FlushRedisCache()
        {
            Stopwatch stopWatch = new Stopwatch();
            stopWatch.Start();
            await Task.Delay(1);
            RedisValue pattern = new RedisValue($"{Const.rKeyConfig}:*");
            bool answ = await ExecFlushRedisPattern(pattern);
            stopWatch.Stop();
            Log.Debug($"FlushRedisCache in {stopWatch.Elapsed.TotalMilliseconds} ms");
            return answ;
        }

        #endregion Public Methods

        #region Protected Fields

        protected static IConfiguration _configuration = null!;
        protected static Logger Log = LogManager.GetCurrentClassLogger();

        /// <summary>
        /// Numero di operazioni parallele che si possono svolgere... (se 0 NON usa cicli paralleli)
        /// </summary>
        protected int numPar = 0;

        /// <summary>
        /// Oggetto per connessione a REDIS
        /// </summary>
        protected IConnectionMultiplexer redisConn = null!;

        /// <summary>
        /// Oggetto DB redis da impiegare x chiamate R/W
        /// </summary>
        protected IDatabase redisDb = null!;

        #endregion Protected Fields

        #region Protected Properties

        protected string CodApp { get; set; } = "";

        /// <summary>
        /// Durata cache breve (1 min circa + perturbazione percentuale +/-10%)
        /// </summary>
        protected TimeSpan FastCache
        {
            get => TimeSpan.FromSeconds(cacheTtlShort * rnd.Next(900, 1100) / 1000);
        }

        /// <summary>
        /// Durata cache lunga (+ perturbazione percentuale +/-10%)
        /// </summary>
        protected TimeSpan LongCache
        {
            get => TimeSpan.FromSeconds(cacheTtlLong * rnd.Next(900, 1100) / 1000);
        }

        /// <summary>
        /// Durata cache MOLTO breve (10 sec circa + perturbazione percentuale +/-10%)
        /// </summary>
        protected TimeSpan UltraFastCache
        {
            get => TimeSpan.FromSeconds(cacheTtlShort / 6 * rnd.Next(900, 1100) / 1000);
        }

        /// <summary>
        /// Durata cache MOLTO lunga (+ perturbazione percentuale +/-10%)
        /// </summary>
        protected TimeSpan UltraLongCache
        {
            get => TimeSpan.FromSeconds(cacheTtlLong * 10 * rnd.Next(900, 1100) / 1000);
        }

        #endregion Protected Properties

        #region Protected Methods

        /// <summary>
        /// Esegue flush memoria redis dato pattern
        /// </summary>
        /// <param name="pattern"></param>
        /// <returns></returns>
        protected async Task<bool> ExecFlushRedisPattern(RedisValue pattern)
        {
            bool answ = false;
            /*******************************
             * Recupero elenco dei server da cui cancellare le chaivi:
             * - prendo solo i server connessi
             * - prendo solo NON repliche (= master)
             * - me ne aspetto 1 in uscita cmq
             *******************************/
            var connServ = redisConn.GetEndPoints()
                                        .Select(endpoint =>
                                        {
                                            var server = redisConn.GetServer(endpoint);
                                            return server;
                                        })
                                        .Where(x => x.IsConnected && !x.IsReplica)
                                        .ToList();

            // ciclo (anche se me ne aspetto 1 solo)
            foreach (var mServer in connServ)
            {
                try
                {
                    var keyList = mServer.Keys(redisDb.Database, pattern);
                    if (numPar > 0)
                    {
                        var options = new ParallelOptions { MaxDegreeOfParallelism = numPar };
                        await Parallel.ForEachAsync(keyList, async (item, token) =>
                        {
                            // cancello
                            await redisDb.KeyDeleteAsync(item);
                        });
                    }
                    else
                    {
                        foreach (var item in keyList)
                        {
                            await redisDb.KeyDeleteAsync(item);
                        }
                    }
                    answ = true;
                }
                catch (Exception exc)
                {
                    Log.Error($"Eccezione durante ExecFlushRedisPattern | pattern: {pattern}{Environment.NewLine}{exc}");
                }
            }
            return answ;
        }

        #endregion Protected Methods

        #region Private Fields

        /// <summary>
        /// Durata cache lunga IN SECONDI
        /// </summary>
        private int cacheTtlLong = 60 * 5;

        /// <summary>
        /// Durata cache breve IN SECONDI
        /// </summary>
        private int cacheTtlShort = 60 * 1;

        private Random rnd = new Random();

        #endregion Private Fields
    }
}