Add a way to get the configured log level switches

Fixes serilog#206

Author: 0xced

src/Serilog.Settings.Configuration/ConfigurationLoggerConfigurationExtensions.cs

@@ -47,6 +47,28 @@ public static LoggerConfiguration Configuration(
         IConfiguration configuration,
         string sectionName,
         DependencyContext dependencyContext = null)
+    {
+        return Configuration(settingConfiguration, configuration, sectionName, out _, dependencyContext);
+    }
+
+    /// <summary>
+    /// Reads logger settings from the provided configuration object using the provided section name. Generally this
+    /// is preferable over the other method that takes a configuration section. Only this version will populate
+    /// IConfiguration parameters on target methods.
+    /// </summary>
+    /// <param name="settingConfiguration">Logger setting configuration.</param>
+    /// <param name="configuration">A configuration object which contains a Serilog section.</param>
+    /// <param name="sectionName">A section name for section which contains a Serilog section.</param>
+    /// <param name="loadedConfiguration">Contains information about the loaded configuration upon return.</param>
+    /// <param name="dependencyContext">The dependency context from which sink/enricher packages can be located. If not supplied, the platform
+    /// default will be used.</param>
+    /// <returns>An object allowing configuration to continue.</returns>
+    public static LoggerConfiguration Configuration(
+        this LoggerSettingsConfiguration settingConfiguration,
+        IConfiguration configuration,
+        string sectionName,
+        out LoadedConfiguration loadedConfiguration,
+        DependencyContext dependencyContext = null)
     {
         if (settingConfiguration == null) throw new ArgumentNullException(nameof(settingConfiguration));
         if (configuration == null) throw new ArgumentNullException(nameof(configuration));
@@ -56,11 +78,10 @@ public static LoggerConfiguration Configuration(
             ? AssemblyFinder.Auto()
             : AssemblyFinder.ForDependencyContext(dependencyContext);
 
-        return settingConfiguration.Settings(
-            new ConfigurationReader(
-                configuration.GetSection(sectionName),
-                assemblyFinder,
-                configuration));
+        var configurationReader = new ConfigurationReader(configuration.GetSection(sectionName), assemblyFinder, configuration);
+        var loggerConfiguration = settingConfiguration.Settings(configurationReader);
+        loadedConfiguration = configurationReader.GetLoadedConfiguration();
+        return loggerConfiguration;
     }
 
     /// <summary>
@@ -79,6 +100,24 @@ public static LoggerConfiguration Configuration(
         DependencyContext dependencyContext = null)
         => Configuration(settingConfiguration, configuration, DefaultSectionName, dependencyContext);
 
+    /// <summary>
+    /// Reads logger settings from the provided configuration object using the default section name. Generally this
+    /// is preferable over the other method that takes a configuration section. Only this version will populate
+    /// IConfiguration parameters on target methods.
+    /// </summary>
+    /// <param name="settingConfiguration">Logger setting configuration.</param>
+    /// <param name="configuration">A configuration object which contains a Serilog section.</param>
+    /// <param name="loadedConfiguration">Contains information about the loaded configuration upon return.</param>
+    /// <param name="dependencyContext">The dependency context from which sink/enricher packages can be located. If not supplied, the platform
+    /// default will be used.</param>
+    /// <returns>An object allowing configuration to continue.</returns>
+    public static LoggerConfiguration Configuration(
+        this LoggerSettingsConfiguration settingConfiguration,
+        IConfiguration configuration,
+        out LoadedConfiguration loadedConfiguration,
+        DependencyContext dependencyContext = null)
+        => Configuration(settingConfiguration, configuration, DefaultSectionName, out loadedConfiguration, dependencyContext);
+
     /// <summary>
     /// Reads logger settings from the provided configuration section. Generally it is preferable to use the other
     /// extension method that takes the full configuration object.
@@ -123,14 +162,36 @@ public static LoggerConfiguration Configuration(
         IConfiguration configuration,
         string sectionName,
         ConfigurationAssemblySource configurationAssemblySource)
+        => Configuration(settingConfiguration, configuration, sectionName, configurationAssemblySource, out _);
+
+    /// <summary>
+    /// Reads logger settings from the provided configuration object using the provided section name. Generally this
+    /// is preferable over the other method that takes a configuration section. Only this version will populate
+    /// IConfiguration parameters on target methods.
+    /// </summary>
+    /// <param name="settingConfiguration">Logger setting configuration.</param>
+    /// <param name="configuration">A configuration object which contains a Serilog section.</param>
+    /// <param name="sectionName">A section name for section which contains a Serilog section.</param>
+    /// <param name="configurationAssemblySource">Defines how the package identifies assemblies to scan for sinks and other types.</param>
+    /// <param name="loadedConfiguration">Contains information about the loaded configuration upon return.</param>
+    /// <returns>An object allowing configuration to continue.</returns>
+    public static LoggerConfiguration Configuration(
+        this LoggerSettingsConfiguration settingConfiguration,
+        IConfiguration configuration,
+        string sectionName,
+        ConfigurationAssemblySource configurationAssemblySource,
+        out LoadedConfiguration loadedConfiguration)
     {
         if (settingConfiguration == null) throw new ArgumentNullException(nameof(settingConfiguration));
         if (configuration == null) throw new ArgumentNullException(nameof(configuration));
         if (sectionName == null) throw new ArgumentNullException(nameof(sectionName));
 
         var assemblyFinder = AssemblyFinder.ForSource(configurationAssemblySource);
 
-        return settingConfiguration.Settings(new ConfigurationReader(configuration.GetSection(sectionName), assemblyFinder, configuration));
+        var configurationReader = new ConfigurationReader(configuration.GetSection(sectionName), assemblyFinder, configuration);
+        var loggerConfiguration = settingConfiguration.Settings(configurationReader);
+        loadedConfiguration = configurationReader.GetLoadedConfiguration();
+        return loggerConfiguration;
     }
 
     /// <summary>
@@ -183,12 +244,32 @@ public static LoggerConfiguration Configuration(
         IConfiguration configuration,
         string sectionName,
         params Assembly[] assemblies)
+        => Configuration(settingConfiguration, configuration, sectionName, out _, assemblies);
+
+    /// <summary>
+    /// Reads logger settings from the provided configuration object using the provided section name.
+    /// </summary>
+    /// <param name="settingConfiguration">Logger setting configuration.</param>
+    /// <param name="configuration">A configuration object which contains a Serilog section.</param>
+    /// <param name="sectionName">A section name for section which contains a Serilog section.</param>
+    /// <param name="loadedConfiguration">Contains information about the loaded configuration upon return.</param>
+    /// <param name="assemblies">A collection of assemblies that contains sinks and other types.</param>
+    /// <returns>An object allowing configuration to continue.</returns>
+    public static LoggerConfiguration Configuration(
+        this LoggerSettingsConfiguration settingConfiguration,
+        IConfiguration configuration,
+        string sectionName,
+        out LoadedConfiguration loadedConfiguration,
+        params Assembly[] assemblies)
     {
         if (settingConfiguration == null) throw new ArgumentNullException(nameof(settingConfiguration));
         if (configuration == null) throw new ArgumentNullException(nameof(configuration));
         if (sectionName == null) throw new ArgumentNullException(nameof(sectionName));
 
-        return settingConfiguration.Settings(new ConfigurationReader(configuration.GetSection(sectionName), assemblies, new ResolutionContext(configuration)));
+        var configurationReader = new ConfigurationReader(configuration.GetSection(sectionName), assemblies, new ResolutionContext(configuration));
+        var loggerConfiguration = settingConfiguration.Settings(configurationReader);
+        loadedConfiguration = configurationReader.GetLoadedConfiguration();
+        return loggerConfiguration;
     }
 
     /// <summary>

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

@@ -58,6 +58,11 @@ public void Configure(LoggerConfiguration loggerConfiguration)
         ApplyAuditSinks(loggerConfiguration);
     }
 
+    public LoadedConfiguration GetLoadedConfiguration()
+    {
+        return new LoadedConfiguration(_resolutionContext.LogLevelSwitches);
+    }
+
     void ProcessFilterSwitchDeclarations()
     {
         var filterSwitchesDirective = _section.GetSection("FilterSwitches");

src/Serilog.Settings.Configuration/Settings/Configuration/LoadedConfiguration.cs

@@ -0,0 +1,22 @@
+using Serilog.Core;
+
+namespace Serilog.Settings.Configuration;
+
+/// <summary>
+/// Contains information about the loaded configuration.
+/// </summary>
+public class LoadedConfiguration
+{
+    readonly IDictionary<string,LoggingLevelSwitch> _logLevelSwitches;
+
+    internal LoadedConfiguration(IDictionary<string, LoggingLevelSwitch> logLevelSwitches)
+    {
+        _logLevelSwitches = logLevelSwitches;
+    }
+
+    /// <summary>
+    /// The log level switches that were loaded from the <c>LevelSwitches</c> section of the configuration.
+    /// </summary>
+    /// <remarks>The keys of the dictionary are the name of the switches without the <c>$</c> character.</remarks>
+    public IReadOnlyDictionary<string, LoggingLevelSwitch> LogLevelSwitches => _logLevelSwitches.ToDictionary(e => e.Key.TrimStart('$'), e => e.Value);
+}

src/Serilog.Settings.Configuration/Settings/Configuration/ResolutionContext.cs

@@ -20,6 +20,8 @@ public ResolutionContext(IConfiguration appConfiguration = null)
         _appConfiguration = appConfiguration;
     }
 
+    public IDictionary<string, LoggingLevelSwitch> LogLevelSwitches => _declaredLevelSwitches;
+
     /// <summary>
     /// Looks up a switch in the declared LoggingLevelSwitches
     /// </summary>

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

@@ -1,4 +1,4 @@
-using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.Configuration;
 using Serilog.Core;
 using Serilog.Events;
 using Serilog.Settings.Configuration.Tests.Support;
@@ -12,22 +12,22 @@ public class ConfigurationSettingsTests
 {
     static LoggerConfiguration ConfigFromJson(string jsonString, string secondJsonSource = null)
     {
-        return ConfigFromJson(jsonString, secondJsonSource, out _);
+        return ConfigFromJson(jsonString, secondJsonSource, out _, out _);
     }
 
-    static LoggerConfiguration ConfigFromJson(string jsonString, out IConfiguration configuration)
+    static LoggerConfiguration ConfigFromJson(string jsonString, out IConfiguration configuration, out LoadedConfiguration loadedConfiguration)
     {
-        return ConfigFromJson(jsonString, null, out configuration);
+        return ConfigFromJson(jsonString, null, out configuration, out loadedConfiguration);
     }
 
-    static LoggerConfiguration ConfigFromJson(string jsonString, string secondJsonSource, out IConfiguration configuration)
+    static LoggerConfiguration ConfigFromJson(string jsonString, string secondJsonSource, out IConfiguration configuration, out LoadedConfiguration loadedConfiguration)
     {
         var builder = new ConfigurationBuilder().AddJsonString(jsonString);
         if (secondJsonSource != null)
             builder.AddJsonString(secondJsonSource);
         configuration = builder.Build();
         return new LoggerConfiguration()
-            .ReadFrom.Configuration(configuration);
+            .ReadFrom.Configuration(configuration, out loadedConfiguration);
     }
 
     [Fact]
@@ -208,7 +208,7 @@ public void TestMinimumLevelOverrides()
 
         LogEvent evt = null;
 
-        var log = ConfigFromJson(json)
+        var log = ConfigFromJson(json, out _, out _)
             .WriteTo.Sink(new DelegatingSink(e => evt = e))
             .CreateLogger();
 
@@ -384,10 +384,12 @@ public void LoggingLevelSwitchIsConfigured(string switchName)
             }}";
         LogEvent evt = null;
 
-        var log = ConfigFromJson(json)
+        var log = ConfigFromJson(json, out _, out var loadedConfiguration)
             .WriteTo.Sink(new DelegatingSink(e => evt = e))
             .CreateLogger();
 
+        Assert.Contains("switch1", loadedConfiguration.LogLevelSwitches);
+        Assert.Equal(LogEventLevel.Warning, loadedConfiguration.LogLevelSwitches["switch1"].MinimumLevel);
         log.Write(Some.DebugEvent());
         Assert.True(evt is null, "LoggingLevelSwitch initial level was Warning. It should not log Debug messages");
         log.Write(Some.InformationEvent());
@@ -542,7 +544,7 @@ public void SinkWithIConfigurationArguments()
             }";
 
         DummyConfigurationSink.Reset();
-        var log = ConfigFromJson(json, out var expectedConfig)
+        var log = ConfigFromJson(json, out var expectedConfig, out _)
             .CreateLogger();
 
         log.Write(Some.InformationEvent());
@@ -566,7 +568,7 @@ public void SinkWithOptionalIConfigurationArguments()
             }";
 
         DummyConfigurationSink.Reset();
-        var log = ConfigFromJson(json, out var expectedConfig)
+        var log = ConfigFromJson(json, out var expectedConfig, out _)
             .CreateLogger();
 
         log.Write(Some.InformationEvent());

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

@@ -47,9 +47,11 @@ public void ShouldRespectDynamicLevelChanges()
     {
         using var logger = new LoggerConfiguration()
             .ReadFrom
-            .Configuration(new ConfigurationBuilder().Add(_configSource).Build())
+            .Configuration(new ConfigurationBuilder().Add(_configSource).Build(), out var loadedConfiguration)
             .CreateLogger();
 
+        Assert.Equal(LogEventLevel.Information, loadedConfiguration.LogLevelSwitches["mySwitch"].MinimumLevel);
+
         DummyConsoleSink.Emitted.Clear();
         logger.Write(Some.DebugEvent());
         Assert.Empty(DummyConsoleSink.Emitted);
@@ -64,6 +66,7 @@ public void ShouldRespectDynamicLevelChanges()
         logger.Write(Some.DebugEvent());
         logger.ForContext(Constants.SourceContextPropertyName, "Root.Test").Write(Some.DebugEvent());
         Assert.Single(DummyConsoleSink.Emitted);
+        Assert.Equal(LogEventLevel.Debug, loadedConfiguration.LogLevelSwitches["mySwitch"].MinimumLevel);
 
         DummyConsoleSink.Emitted.Clear();
         UpdateConfig(overrideLevel: LogEventLevel.Debug);