Support of constructor parameters

CHANGES.md

@@ -1,5 +1,9 @@
 # Changelog
 
+3.3.0
+
+* #276, #225, #167 - added support for constructors with arguments for complex types
+
 3.2.0
 
 * #162 - LoggingFilterSwitch support

README.md

@@ -284,7 +284,22 @@ Static member access can be used for passing to the configuration argument via [
 
 ### Complex parameter value binding
 
-If the parameter value is not a discrete value, the package will use the configuration binding system provided by _[Microsoft.Extensions.Options.ConfigurationExtensions](https://www.nuget.org/packages/Microsoft.Extensions.Options.ConfigurationExtensions/)_ to attempt to populate the parameter. Almost anything that can be bound by `IConfiguration.Get<T>` should work with this package. An example of this is the optional `List<Column>` parameter used to configure the .NET Standard version of the _[Serilog.Sinks.MSSqlServer](https://github.com/serilog/serilog-sinks-mssqlserver)_ package.
+If the parameter value is not a discrete value, it will try to find a best matching public constructor for the argument:
+
+```json
+{
+  "Name": "Console",
+  "Args": {
+    "formatter": {
+      // `type` (or $type) is optional, must be specified for abstract declared parameter types
+      "type": "Serilog.Templates.ExpressionTemplate, Serilog.Expressions",
+      "template": "[{@t:HH:mm:ss} {@l:u3} {Coalesce(SourceContext, '<none>')}] {@m}\n{@x}",
+      "formatProvider": "System.Globalization.CultureInfo::InvariantCulture"
+  }
+}
+```
+
+For other cases the package will use the configuration binding system provided by _[Microsoft.Extensions.Options.ConfigurationExtensions](https://www.nuget.org/packages/Microsoft.Extensions.Options.ConfigurationExtensions/)_ to attempt to populate the parameter. Almost anything that can be bound by `IConfiguration.Get<T>` should work with this package. An example of this is the optional `List<Column>` parameter used to configure the .NET Standard version of the _[Serilog.Sinks.MSSqlServer](https://github.com/serilog/serilog-sinks-mssqlserver)_ package.
 
 ### Abstract parameter types
 

sample/Sample/Program.cs

@@ -63,9 +63,16 @@ public static void Main(string[] args)
     // processed by the Serilog.Filters.Expressions package.
     public class CustomFilter : ILogEventFilter
     {
+        readonly LogEventLevel _levelFilter;
+
+        public CustomFilter(LogEventLevel levelFilter = LogEventLevel.Information)
+        {
+            _levelFilter = levelFilter;
+        }
+
         public bool IsEnabled(LogEvent logEvent)
         {
-            return true;
+            return logEvent.Level >= _levelFilter;
         }
     }
 

sample/Sample/Sample.csproj

@@ -38,6 +38,7 @@
     <PackageReference Include="Serilog.Sinks.Console" Version="3.1.1" />
     <PackageReference Include="Serilog.Sinks.File" Version="4.1.0" />
     <PackageReference Include="Serilog.Enrichers.Environment" Version="2.1.3" />
+    <PackageReference Include="Serilog.Formatting.Compact" Version="1.1.0" />
     <PackageReference Include="Serilog.Enrichers.Thread" Version="3.1.0" />
   </ItemGroup>
 

sample/Sample/appsettings.json

@@ -51,7 +51,13 @@
           {
             "Name": "File",
             "Args": {
-              "path": "%TEMP%/Logs/serilog-configuration-sample-errors.txt"
+              "path": "%TEMP%/Logs/serilog-configuration-sample-errors.txt",
+              "formatter": {
+                "type": "Serilog.Formatting.Compact.CompactJsonFormatter, Serilog.Formatting.Compact",
+                "valueFormatter": {
+                  "typeTagName": "customTypeTag"
+                }
+              }
             }
           }
         ]
@@ -106,7 +112,10 @@
       {
         "Name": "With",
         "Args": {
-          "filter": "Sample.CustomFilter, Sample"
+          "filter": {
+            "type": "Sample.CustomFilter, Sample",
+            "levelFilter": "Verbose"
+          }
         }
       }
     ]

src/Serilog.Settings.Configuration/Serilog.Settings.Configuration.csproj

@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <Description>Microsoft.Extensions.Configuration (appsettings.json) support for Serilog.</Description>
-    <VersionPrefix>3.2.1</VersionPrefix>
+    <VersionPrefix>3.3.0</VersionPrefix>
     <LangVersion>latest</LangVersion>
     <Authors>Serilog Contributors</Authors>
     <TargetFrameworks>netstandard2.0;net451;net461</TargetFrameworks>

src/Serilog.Settings.Configuration/Settings/Configuration/ObjectArgumentValue.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Linq.Expressions;
 using System.Reflection;
 
 using Microsoft.Extensions.Configuration;
@@ -50,6 +51,11 @@ public object ConvertTo(Type toType, ResolutionContext resolutionContext)
             if (IsContainer(toType, out var elementType) && TryCreateContainer(out var result))
                 return result;
 
+            if (TryBuildCtorExpression(_section, toType, resolutionContext, out var ctorExpression))
+            {
+                return Expression.Lambda<Func<object>>(ctorExpression).Compile().Invoke();
+            }
+
             // MS Config binding can work with a limited set of primitive types and collections
             return _section.Get(toType);
 
@@ -94,6 +100,126 @@ bool TryCreateContainer(out object result)
             }
         }
 
+        internal static bool TryBuildCtorExpression(
+            IConfigurationSection section, Type parameterType, ResolutionContext resolutionContext, out NewExpression ctorExpression)
+        {
+            ctorExpression = null;
+
+            var typeDirective = section.GetValue<string>("$type") switch
+            {
+                not null => "$type",
+                null => section.GetValue<string>("type") switch
+                {
+                    not null => "type",
+                    null => null,
+                },
+            };
+
+            var type = typeDirective switch
+            {
+                not null => Type.GetType(section.GetValue<string>(typeDirective), throwOnError: false),
+                null => parameterType,
+            };
+
+            if (type is null or { IsAbstract: true })
+            {
+                return false;
+            }
+
+            var suppliedArguments = section.GetChildren().Where(s => s.Key != typeDirective)
+                .ToDictionary(s => s.Key, StringComparer.OrdinalIgnoreCase);
+
+            if (suppliedArguments.Count == 0 &&
+                type.GetConstructor(Type.EmptyTypes) is ConstructorInfo parameterlessCtor)
+            {
+                ctorExpression = Expression.New(parameterlessCtor);
+                return true;
+            }
+
+            var ctor =
+                (from c in type.GetConstructors()
+                 from p in c.GetParameters()
+                 let argumentBindResult = suppliedArguments.TryGetValue(p.Name, out var argValue) switch
+                 {
+                     true => new { success = true, hasMatch = true, value = (object)argValue },
+                     false => p.HasDefaultValue switch
+                     {
+                         true  => new { success = true,  hasMatch = false, value = p.DefaultValue },
+                         false => new { success = false, hasMatch = false, value = (object)null },
+                     },
+                 }
+                 group new { argumentBindResult, p.ParameterType } by c into gr
+                 where gr.All(z => z.argumentBindResult.success)
+                 let matchedArgs = gr.Where(z => z.argumentBindResult.hasMatch).ToList()
+                 orderby matchedArgs.Count descending,
+                         matchedArgs.Count(p => p.ParameterType == typeof(string)) descending
+                 select new
+                 {
+                     ConstructorInfo = gr.Key,
+                     ArgumentValues = gr.Select(z => new { Value = z.argumentBindResult.value, Type = z.ParameterType })
+                                        .ToList()
+                 }).FirstOrDefault();
+
+            if (ctor is null)
+            {
+                return false;
+            }
+
+            var ctorArguments = new List<Expression>();
+            foreach (var argumentValue in ctor.ArgumentValues)
+            {
+                if (TryBindToCtorArgument(argumentValue.Value, argumentValue.Type, resolutionContext, out var argumentExpression))
+                {
+                    ctorArguments.Add(argumentExpression);
+                }
+                else
+                {
+                    return false;
+                }
+            }
+
+            ctorExpression = Expression.New(ctor.ConstructorInfo, ctorArguments);
+            return true;
+
+            static bool TryBindToCtorArgument(object value, Type type, ResolutionContext resolutionContext, out Expression argumentExpression)
+            {
+                argumentExpression = null;
+
+                if (value is IConfigurationSection s)
+                {
+                    if (s.Value is string argValue)
+                    {
+                        var stringArgumentValue = new StringArgumentValue(argValue);
+                        try
+                        {
+                            argumentExpression = Expression.Constant(
+                                stringArgumentValue.ConvertTo(type, resolutionContext),
+                                type);
+
+                            return true;
+                        }
+                        catch (Exception)
+                        {
+                            return false;
+                        }
+                    }
+                    else if (s.GetChildren().Any())
+                    {
+                        if (TryBuildCtorExpression(s, type, resolutionContext, out var ctorExpression))
+                        {
+                            argumentExpression = ctorExpression;
+                            return true;
+                        }
+
+                        return false;
+                    }
+                }
+
+                argumentExpression = Expression.Constant(value, type);
+                return true;
+            }
+        }
+
         static bool IsContainer(Type type, out Type elementType)
         {
             elementType = null;

test/Serilog.Settings.Configuration.Tests/ObjectArgumentValueTests.cs

@@ -0,0 +1,68 @@
+using System;
+
+using Microsoft.Extensions.Configuration;
+
+using Xunit;
+
+namespace Serilog.Settings.Configuration.Tests
+{
+    public class ObjectArgumentValueTests
+    {
+        readonly IConfigurationRoot _config;
+
+        public ObjectArgumentValueTests()
+        {
+            _config = new ConfigurationBuilder()
+                .AddJsonFile("ObjectArgumentValueTests.json")
+                .Build();
+        }
+
+        [Theory]
+        [InlineData("case_1", typeof(A), "new A(1, 23:59:59, http://dot.com/, \"d\")")]
+        [InlineData("case_2", typeof(B), "new B(2, new A(3, new D()), null)")]
+        [InlineData("case_3", typeof(E), "new E(\"1\", \"2\", \"3\")")]
+        [InlineData("case_4", typeof(F), "new F(\"paramType\", new E(1, 2, 3, 4))")]
+        [InlineData("case_5", typeof(G), "new G()")]
+        [InlineData("case_6", typeof(G), "new G(3, 4)")]
+        public void ShouldBindToConstructorArguments(string caseSection, Type targetType, string expectedExpression)
+        {
+            var testSection = _config.GetSection(caseSection);
+
+            Assert.True(ObjectArgumentValue.TryBuildCtorExpression(testSection, targetType, new(), out var ctorExpression));
+            Assert.Equal(expectedExpression, ctorExpression.ToString());
+        }
+
+        class A
+        {
+            public A(int a, TimeSpan b, Uri c, string d = "d") { }
+            public A(int a, C c) { }
+        }
+
+        class B
+        {
+            public B(int b, A a, long? c = null) { }
+        }
+
+        interface C { }
+
+        class D : C { }
+
+        class E
+        {
+            public E(int a, int b, int c, int d = 4) { }
+            public E(int a, string b, string c) { }
+            public E(string a, string b, string c) { }
+        }
+
+        class F
+        {
+            public F(string type, E e) { }
+        }
+
+        class G
+        {
+            public G() { }
+            public G(int a = 1, int b = 2) { }
+        }
+    }
+}

test/Serilog.Settings.Configuration.Tests/ObjectArgumentValueTests.json

@@ -0,0 +1,44 @@
+{
+  "case_1": {
+    "A": 1,
+    "b": "23:59:59",
+    "c": "http://dot.com/"
+  },
+
+  "case_2": {
+    "b": 2,
+    "A": {
+      "a": 3,
+      "c": {
+        "type": "Serilog.Settings.Configuration.Tests.ObjectArgumentValueTests+D, Serilog.Settings.Configuration.Tests"
+      }
+    }
+  },
+
+  "case_3": {
+    "a": 1,
+    "b": 2,
+    "c": 3
+  },
+
+  "case_4": {
+    "$type": "Serilog.Settings.Configuration.Tests.ObjectArgumentValueTests+F, Serilog.Settings.Configuration.Tests",
+    "type": "paramType",
+    "e": {
+      "type": "Serilog.Settings.Configuration.Tests.ObjectArgumentValueTests+E, Serilog.Settings.Configuration.Tests",
+      "a": 1,
+      "b": 2,
+      "c": 3,
+      "d": 4
+    }
+  },
+
+  "case_5": {
+
+  },
+
+  "case_6": {
+    "a": 3,
+    "b": 4
+  }
+}

test/Serilog.Settings.Configuration.Tests/Serilog.Settings.Configuration.Tests.csproj

@@ -12,6 +12,12 @@
   <PropertyGroup Condition="'$(TargetFramework)' == 'net452'">
     <DefineConstants>$(DefineConstants);PRIVATE_BIN</DefineConstants>
   </PropertyGroup>
+
+  <ItemGroup>
+    <None Include="*.json">
+      <CopyToOutputDirectory>Always</CopyToOutputDirectory>
+    </None>
+  </ItemGroup>
 
   <ItemGroup>
     <ProjectReference Include="..\..\src\Serilog.Settings.Configuration\Serilog.Settings.Configuration.csproj" />
@@ -35,7 +41,7 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.8.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.11.0" />
     <PackageReference Include="Serilog.Filters.Expressions" Version="2.0.0" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.2.0" />
     <PackageReference Include="xunit" Version="2.2.0" />