Readarr/src/NzbDrone.Core/Instrumentation/ReconfigureLogging.cs

using System.Collections.Generic;
using System.Linq;
using NLog;
using NLog.Config;
using NzbDrone.Common.Extensions;
using NzbDrone.Core.Configuration;
using NzbDrone.Core.Configuration.Events;
using NzbDrone.Core.Messaging.Events;

namespace NzbDrone.Core.Instrumentation
{
    public class ReconfigureLogging : IHandleAsync<ConfigFileSavedEvent>
    {
        private readonly IConfigFileProvider _configFileProvider;

        public ReconfigureLogging(IConfigFileProvider configFileProvider)
        {
            _configFileProvider = configFileProvider;
        }

        public void Reconfigure()
        {
            var minimumLogLevel = LogLevel.FromString(_configFileProvider.LogLevel);
            LogLevel minimumConsoleLogLevel;

            if (_configFileProvider.ConsoleLogLevel.IsNotNullOrWhiteSpace())
                minimumConsoleLogLevel = LogLevel.FromString(_configFileProvider.ConsoleLogLevel);
            else if (minimumLogLevel > LogLevel.Info)
                minimumConsoleLogLevel = minimumLogLevel;
            else
                minimumConsoleLogLevel = LogLevel.Info;

            var rules = LogManager.Configuration.LoggingRules;

            //Console
            SetMinimumLogLevel(rules, "consoleLogger", minimumConsoleLogLevel);

            //Log Files
            SetMinimumLogLevel(rules, "appFileInfo", minimumLogLevel <= LogLevel.Info ? LogLevel.Info : LogLevel.Off);
            SetMinimumLogLevel(rules, "appFileDebug", minimumLogLevel <= LogLevel.Debug ? LogLevel.Debug : LogLevel.Off);
            SetMinimumLogLevel(rules, "appFileTrace", minimumLogLevel <= LogLevel.Trace ? LogLevel.Trace : LogLevel.Off);

            LogManager.ReconfigExistingLoggers();
        }

        private void SetMinimumLogLevel(IList<LoggingRule> rules, string target, LogLevel minimumLogLevel)
        {
            foreach (var rule in rules.Where(v => v.Targets.Any(t => t.Name == target)))
            {
                SetMinimumLogLevel(rule, minimumLogLevel);
            }
        }

        private void SetMinimumLogLevel(LoggingRule rule, LogLevel minimumLogLevel)
        {
            foreach (var logLevel in GetLogLevels())
            {
                if (logLevel < minimumLogLevel)
                {
                    rule.DisableLoggingForLevel(logLevel);
                }

                else
                {
                    rule.EnableLoggingForLevel(logLevel);
                }
            }
        }

        private List<LogLevel> GetLogLevels()
        {
            return new List<LogLevel>
                       {
                           LogLevel.Trace,
                           LogLevel.Debug,
                           LogLevel.Info,
                           LogLevel.Warn,
                           LogLevel.Error,
                           LogLevel.Fatal
                       };
        }

        public void HandleAsync(ConfigFileSavedEvent message)
        {
            Reconfigure();
        }
    }
}