Refactor ConfigurationReader and move Surrogate methods to a separate class

Author: tsimbalar

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

@@ -11,7 +11,6 @@
 using Serilog.Core;
 using Serilog.Debugging;
 using Serilog.Events;
-using System.Linq.Expressions;
 using System.Text.RegularExpressions;
 
 namespace Serilog.Settings.Configuration
@@ -354,7 +353,7 @@ internal static IList<MethodInfo> FindSinkConfigurationMethods(IReadOnlyCollecti
         {
             var found = FindConfigurationExtensionMethods(configurationAssemblies, typeof(LoggerSinkConfiguration));
             if (configurationAssemblies.Contains(typeof(LoggerSinkConfiguration).GetTypeInfo().Assembly))
-                found.Add(GetSurrogateConfigurationMethod<LoggerSinkConfiguration, Action<LoggerConfiguration>, LoggingLevelSwitch>((c, a, s) => Logger(c, a, LevelAlias.Minimum, s)));
+                found.AddRange(SurrogateConfigurationMethods.WriteTo);
 
             return found;
         }
@@ -370,7 +369,7 @@ internal static IList<MethodInfo> FindFilterConfigurationMethods(IReadOnlyCollec
         {
             var found = FindConfigurationExtensionMethods(configurationAssemblies, typeof(LoggerFilterConfiguration));
             if (configurationAssemblies.Contains(typeof(LoggerFilterConfiguration).GetTypeInfo().Assembly))
-                found.Add(GetSurrogateConfigurationMethod<LoggerFilterConfiguration, ILogEventFilter, object>((c, f, _) => With(c, f)));
+                found.AddRange(SurrogateConfigurationMethods.Filter);
 
             return found;
         }
@@ -379,13 +378,7 @@ internal static IList<MethodInfo> FindDestructureConfigurationMethods(IReadOnlyC
         {
             var found = FindConfigurationExtensionMethods(configurationAssemblies, typeof(LoggerDestructuringConfiguration));
             if (configurationAssemblies.Contains(typeof(LoggerDestructuringConfiguration).GetTypeInfo().Assembly))
-            {
-                found.Add(GetSurrogateConfigurationMethod<LoggerDestructuringConfiguration, IDestructuringPolicy, object>((c, d, _) => With(c, d)));
-                found.Add(GetSurrogateConfigurationMethod<LoggerDestructuringConfiguration, int, object>((c, m, _) => ToMaximumDepth(c, m)));
-                found.Add(GetSurrogateConfigurationMethod<LoggerDestructuringConfiguration, int, object>((c, m, _) => ToMaximumStringLength(c, m)));
-                found.Add(GetSurrogateConfigurationMethod<LoggerDestructuringConfiguration, int, object>((c, m, _) => ToMaximumCollectionCount(c, m)));
-                found.Add(GetSurrogateConfigurationMethod<LoggerDestructuringConfiguration, Type, object>((c, t, _) => AsScalar(c, t)));
-            }
+                found.AddRange(SurrogateConfigurationMethods.Destructure);
 
             return found;
         }
@@ -394,12 +387,12 @@ internal static IList<MethodInfo> FindEventEnricherConfigurationMethods(IReadOnl
         {
             var found = FindConfigurationExtensionMethods(configurationAssemblies, typeof(LoggerEnrichmentConfiguration));
             if (configurationAssemblies.Contains(typeof(LoggerEnrichmentConfiguration).GetTypeInfo().Assembly))
-                found.Add(GetSurrogateConfigurationMethod<LoggerEnrichmentConfiguration, object, object>((c, _, __) => FromLogContext(c)));
+                found.AddRange(SurrogateConfigurationMethods.Enrich);
 
             return found;
         }
 
-        internal static IList<MethodInfo> FindConfigurationExtensionMethods(IReadOnlyCollection<Assembly> configurationAssemblies, Type configType)
+        internal static List<MethodInfo> FindConfigurationExtensionMethods(IReadOnlyCollection<Assembly> configurationAssemblies, Type configType)
         {
             return configurationAssemblies
                 .SelectMany(a => a.ExportedTypes
@@ -411,48 +404,6 @@ internal static IList<MethodInfo> FindConfigurationExtensionMethods(IReadOnlyCol
                 .ToList();
         }
 
-        /*
-        Pass-through calls to various Serilog config methods which are
-        implemented as instance methods rather than extension methods. The
-        FindXXXConfigurationMethods calls (above) use these to add method
-        invocation expressions as surrogates so that SelectConfigurationMethod
-        has a way to match and invoke these instance methods.
-        */
-
-        // TODO: add overload for array argument (ILogEventEnricher[])
-        internal static LoggerConfiguration With(LoggerFilterConfiguration loggerFilterConfiguration, ILogEventFilter filter)
-            => loggerFilterConfiguration.With(filter);
-
-        // TODO: add overload for array argument (IDestructuringPolicy[])
-        internal static LoggerConfiguration With(LoggerDestructuringConfiguration loggerDestructuringConfiguration, IDestructuringPolicy policy)
-            => loggerDestructuringConfiguration.With(policy);
-
-        internal static LoggerConfiguration ToMaximumDepth(LoggerDestructuringConfiguration loggerDestructuringConfiguration, int maximumDestructuringDepth)
-            => loggerDestructuringConfiguration.ToMaximumDepth(maximumDestructuringDepth);
-
-        internal static LoggerConfiguration ToMaximumStringLength(LoggerDestructuringConfiguration loggerDestructuringConfiguration, int maximumStringLength)
-            => loggerDestructuringConfiguration.ToMaximumStringLength(maximumStringLength);
-
-        internal static LoggerConfiguration ToMaximumCollectionCount(LoggerDestructuringConfiguration loggerDestructuringConfiguration, int maximumCollectionCount)
-            => loggerDestructuringConfiguration.ToMaximumCollectionCount(maximumCollectionCount);
-
-        internal static LoggerConfiguration AsScalar(LoggerDestructuringConfiguration loggerDestructuringConfiguration, Type scalarType)
-            => loggerDestructuringConfiguration.AsScalar(scalarType);
-
-        internal static LoggerConfiguration FromLogContext(LoggerEnrichmentConfiguration loggerEnrichmentConfiguration)
-            => loggerEnrichmentConfiguration.FromLogContext();
-
-        // Unlike the other configuration methods, Logger is an instance method rather than an extension.
-        internal static LoggerConfiguration Logger(
-            LoggerSinkConfiguration loggerSinkConfiguration,
-            Action<LoggerConfiguration> configureLogger,
-            LogEventLevel restrictedToMinimumLevel = LevelAlias.Minimum,
-            LoggingLevelSwitch levelSwitch = null)
-            => loggerSinkConfiguration.Logger(configureLogger, restrictedToMinimumLevel, levelSwitch);
-
-        internal static MethodInfo GetSurrogateConfigurationMethod<TConfiguration, TArg1, TArg2>(Expression<Action<TConfiguration, TArg1, TArg2>> method)
-            => (method.Body as MethodCallExpression)?.Method;
-
         internal static bool IsValidSwitchName(string input)
         {
             return Regex.IsMatch(input, LevelSwitchNameRegex);

src/Serilog.Settings.Configuration/Settings/Configuration/SurrogateConfigurationMethods.cs

@@ -0,0 +1,99 @@
+using System;
+using System.Collections.Generic;
+using System.Linq.Expressions;
+using System.Reflection;
+using Serilog.Configuration;
+using Serilog.Core;
+using Serilog.Events;
+
+namespace Serilog.Settings.Configuration
+{
+    /// <summary>
+    /// Contains "fake extension" methods for the Serilog configuration API.
+    /// By default the settings knows how to find extension methods, but some configuration
+    /// are actually "regular" method calls and would not be found otherwise.
+    ///
+    /// This static class contains internal methods that can be used instead.
+    ///
+    /// </summary>
+    static class SurrogateConfigurationMethods
+    {
+        public static IEnumerable<MethodInfo> WriteTo
+        {
+            get
+            {
+                yield return GetSurrogateConfigurationMethod<LoggerSinkConfiguration, Action<LoggerConfiguration>, LoggingLevelSwitch>((c, a, s) => Logger(c, a, LevelAlias.Minimum, s));
+            }
+        }
+
+        public static IEnumerable<MethodInfo> Filter
+        {
+            get
+            {
+                yield return GetSurrogateConfigurationMethod<LoggerFilterConfiguration, ILogEventFilter, object>((c, f, _) => With(c, f));
+            }
+        }
+
+        public static IEnumerable<MethodInfo> Destructure
+        {
+            get
+            {
+                yield return GetSurrogateConfigurationMethod<LoggerDestructuringConfiguration, IDestructuringPolicy, object>((c, d, _) => With(c, d));
+                yield return GetSurrogateConfigurationMethod<LoggerDestructuringConfiguration, int, object>((c, m, _) => ToMaximumDepth(c, m));
+                yield return GetSurrogateConfigurationMethod<LoggerDestructuringConfiguration, int, object>((c, m, _) => ToMaximumStringLength(c, m));
+                yield return GetSurrogateConfigurationMethod<LoggerDestructuringConfiguration, int, object>((c, m, _) => ToMaximumCollectionCount(c, m));
+                yield return GetSurrogateConfigurationMethod<LoggerDestructuringConfiguration, Type, object>((c, t, _) => AsScalar(c, t));
+            }
+        }
+
+        public static IEnumerable<MethodInfo> Enrich
+        {
+            get
+            {
+                yield return GetSurrogateConfigurationMethod<LoggerEnrichmentConfiguration, object, object>((c, _, __) => FromLogContext(c));
+            }
+        }
+
+        static MethodInfo GetSurrogateConfigurationMethod<TConfiguration, TArg1, TArg2>(Expression<Action<TConfiguration, TArg1, TArg2>> method)
+            => (method.Body as MethodCallExpression)?.Method;
+
+        /*
+        Pass-through calls to various Serilog config methods which are
+        implemented as instance methods rather than extension methods. The
+        FindXXXConfigurationMethods calls (above) use these to add method
+        invocation expressions as surrogates so that SelectConfigurationMethod
+        has a way to match and invoke these instance methods.
+        */
+
+        // TODO: add overload for array argument (ILogEventEnricher[])
+        static LoggerConfiguration With(LoggerFilterConfiguration loggerFilterConfiguration, ILogEventFilter filter)
+            => loggerFilterConfiguration.With(filter);
+
+        // TODO: add overload for array argument (IDestructuringPolicy[])
+        static LoggerConfiguration With(LoggerDestructuringConfiguration loggerDestructuringConfiguration, IDestructuringPolicy policy)
+            => loggerDestructuringConfiguration.With(policy);
+
+        static LoggerConfiguration ToMaximumDepth(LoggerDestructuringConfiguration loggerDestructuringConfiguration, int maximumDestructuringDepth)
+            => loggerDestructuringConfiguration.ToMaximumDepth(maximumDestructuringDepth);
+
+        static LoggerConfiguration ToMaximumStringLength(LoggerDestructuringConfiguration loggerDestructuringConfiguration, int maximumStringLength)
+            => loggerDestructuringConfiguration.ToMaximumStringLength(maximumStringLength);
+
+        static LoggerConfiguration ToMaximumCollectionCount(LoggerDestructuringConfiguration loggerDestructuringConfiguration, int maximumCollectionCount)
+            => loggerDestructuringConfiguration.ToMaximumCollectionCount(maximumCollectionCount);
+
+        static LoggerConfiguration AsScalar(LoggerDestructuringConfiguration loggerDestructuringConfiguration, Type scalarType)
+            => loggerDestructuringConfiguration.AsScalar(scalarType);
+
+        static LoggerConfiguration FromLogContext(LoggerEnrichmentConfiguration loggerEnrichmentConfiguration)
+            => loggerEnrichmentConfiguration.FromLogContext();
+
+        // Unlike the other configuration methods, Logger is an instance method rather than an extension.
+        static LoggerConfiguration Logger(
+            LoggerSinkConfiguration loggerSinkConfiguration,
+            Action<LoggerConfiguration> configureLogger,
+            LogEventLevel restrictedToMinimumLevel = LevelAlias.Minimum,
+            LoggingLevelSwitch levelSwitch = null)
+            => loggerSinkConfiguration.Logger(configureLogger, restrictedToMinimumLevel, levelSwitch);
+    }
+}