Minimumlevel partial fix with IConfigurationRoot.Providers

A partial fix for minimumlevel not being correctly overriden by higher priority providers.

Author: Bánhegyi Álmos

src/Serilog.Settings.Configuration/Settings/Configuration/ConfigurationReader.cs

@@ -22,12 +22,19 @@ class ConfigurationReader : IConfigurationReader
         readonly IConfigurationSection _section;
         readonly IReadOnlyCollection<Assembly> _configurationAssemblies;
         readonly ResolutionContext _resolutionContext;
+#if NETSTANDARD || NET461
+        readonly IConfigurationRoot _configurationRoot;
+#endif
 
         public ConfigurationReader(IConfigurationSection configSection, AssemblyFinder assemblyFinder, IConfiguration configuration = null)
         {
             _section = configSection ?? throw new ArgumentNullException(nameof(configSection));
             _configurationAssemblies = LoadConfigurationAssemblies(_section, assemblyFinder);
             _resolutionContext = new ResolutionContext(configuration);
+#if NETSTANDARD || NET461
+            _configurationRoot = configuration as IConfigurationRoot;
+#endif
+
         }
 
         // Used internally for processing nested configuration sections -- see GetMethodCalls below.
@@ -85,7 +92,7 @@ void ApplyMinimumLevel(LoggerConfiguration loggerConfiguration)
         {
             var minimumLevelDirective = _section.GetSection("MinimumLevel");
 
-            var defaultMinLevelDirective = minimumLevelDirective.Value != null ? minimumLevelDirective : minimumLevelDirective.GetSection("Default");
+            IConfigurationSection defaultMinLevelDirective = GetDefaultMinLevelDirective();
             if (defaultMinLevelDirective.Value != null)
             {
                 ApplyMinimumLevel(defaultMinLevelDirective, (configuration, levelSwitch) => configuration.ControlledBy(levelSwitch));
@@ -124,6 +131,35 @@ void ApplyMinimumLevel(IConfigurationSection directive, Action<LoggerMinimumLeve
 
                 SubscribeToLoggingLevelChanges(directive, levelSwitch);
             }
+
+            IConfigurationSection GetDefaultMinLevelDirective()
+            {
+                #if NETSTANDARD || NET461
+
+                var defaultLevelDirective = minimumLevelDirective.GetSection("Default");
+                if (_configurationRoot != null && minimumLevelDirective.Value != null && defaultLevelDirective.Value != null)
+                {
+                    foreach (var provider in _configurationRoot.Providers.Reverse())
+                    {
+                        if (provider.TryGet(minimumLevelDirective.Path, out _))
+                        {
+                            return _configurationRoot.GetSection(minimumLevelDirective.Path);
+                        }
+
+                        if (provider.TryGet(defaultLevelDirective.Path, out _))
+                        {
+                            return _configurationRoot.GetSection(defaultLevelDirective.Path);
+                        }
+                    }
+
+                    return null;
+                }
+
+                #endif //NET451 or fallback
+
+                return minimumLevelDirective.Value != null ? minimumLevelDirective : minimumLevelDirective.GetSection("Default");
+
+            }
         }
 
         void SubscribeToLoggingLevelChanges(IConfigurationSection levelSection, LoggingLevelSwitch levelSwitch)