Add native logging for emitters #1837

docs/CHANGELOG-v3.md

@@ -36,6 +36,9 @@ What's changed since pre-release v3.0.0-B0203:
     - With this update rules with the severity level `Error` that fail will break the pipeline by default.
     - The `Execution.Break` option can be set to `Never`, `OnError`, `OnWarning`, or `OnInformation`.
     - If a rule fails with a severity level equal or higher than the configured level the pipeline will break.
+- General improvements:
+  - Added support for native logging within emitters by @BernieWhite.
+    [#1837](https://github.com/microsoft/PSRule/issues/1837)
 - Engineering:
   - Bump xunit to v2.9.0.
     [#1869](https://github.com/microsoft/PSRule/pull/1869)

docs/specs/emitter-spec.md

@@ -25,5 +25,16 @@ Goals with emitters:
 
 The goal of emitters is to provide a high performance and extensible way to emit custom objects to the input stream.
 
-Emitters define a C# `IEmitter` interface for emitting objects to the input stream.
+Emitters define an `IEmitter` interface for emitting objects to the input stream.
 The implementation of an emitter must be thread safe, as emitters can be run in parallel.
+
+## Logging
+
+An emitter may expose diagnostic logs by using the `PSRule.Runtime.ILogger<T>` interface.
+
+## Dependency injection
+
+PSRule uses dependency injection to create each emitter instance.
+The following interfaces can optionally be specified in a emitter constructor to have references injected to the instance.
+
+- `PSRule.Runtime.ILogger<T>`

src/PSRule.Types/Runtime/ILoggerFactory.cs

@@ -0,0 +1,17 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+namespace PSRule.Runtime;
+
+/// <summary>
+/// A factory that creates loggers.
+/// </summary>
+public interface ILoggerFactory
+{
+    /// <summary>
+    /// A factory for creating loggers.
+    /// </summary>
+    /// <param name="categoryName">The category name for messages produced by the logger.</param>
+    /// <returns>Create an instance of an <see cref="ILogger"/> with the specified category name.</returns>
+    ILogger Create(string categoryName);
+}

src/PSRule.Types/Runtime/ILogger_TCategoryName.cs

@@ -0,0 +1,13 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+namespace PSRule.Runtime;
+
+/// <summary>
+/// Log diagnostic messages at runtime.
+/// </summary>
+/// <typeparam name="TCategoryName">The type name to use for the logger category.</typeparam>
+public interface ILogger<out TCategoryName> : ILogger
+{
+
+}

src/PSRule.Types/Runtime/Logger_T.cs

@@ -0,0 +1,30 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+namespace PSRule.Runtime;
+
+/// <summary>
+/// Log diagnostic messages at runtime.
+/// </summary>
+/// <typeparam name="T">The type name to use for the logger category.</typeparam>
+public sealed class Logger<T>(ILoggerFactory loggerFactory) : ILogger<T>
+{
+    private readonly ILogger _Logger = loggerFactory.Create(typeof(T).FullName);
+
+    /// <summary>
+    /// The name of the category.
+    /// </summary>
+    public string CategoryName => typeof(T).Name;
+
+    /// <inheritdoc/>
+    public bool IsEnabled(LogLevel logLevel)
+    {
+        return _Logger.IsEnabled(logLevel);
+    }
+
+    /// <inheritdoc/>
+    public void Log<TState>(LogLevel logLevel, EventId eventId, TState state, Exception? exception, Func<TState, Exception?, string> formatter)
+    {
+        _Logger.Log(logLevel, eventId, state, exception, formatter);
+    }
+}

src/PSRule.Types/Runtime/NullLogger.cs

@@ -0,0 +1,28 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+
+namespace PSRule.Runtime;
+
+/// <summary>
+/// A logger that sinks all logs.
+/// </summary>
+public sealed class NullLogger : ILogger
+{
+    /// <summary>
+    /// An default instance of the null logger.
+    /// </summary>
+    public static readonly NullLogger Instance = new();
+
+    /// <inheritdoc/>
+    public bool IsEnabled(LogLevel logLevel)
+    {
+        return false;
+    }
+
+    /// <inheritdoc/>
+    public void Log<TState>(LogLevel logLevel, EventId eventId, TState state, Exception? exception, Func<TState, Exception?, string> formatter)
+    {
+
+    }
+}

src/PSRule.Types/Runtime/NullLogger_T.cs

@@ -0,0 +1,27 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+namespace PSRule.Runtime;
+
+/// <summary>
+/// A logger that sinks all logs.
+/// </summary>
+public sealed class NullLogger<T> : ILogger<T>
+{
+    /// <summary>
+    /// An default instance of the null logger.
+    /// </summary>
+    public static readonly NullLogger<T> Instance = new();
+
+    /// <inheritdoc/>
+    public bool IsEnabled(LogLevel logLevel)
+    {
+        return false;
+    }
+
+    /// <inheritdoc/>
+    public void Log<TState>(LogLevel logLevel, EventId eventId, TState state, Exception? exception, Func<TState, Exception?, string> formatter)
+    {
+
+    }
+}

src/PSRule/Commands/ExportConventionCommand.cs

@@ -99,7 +99,7 @@ protected override void ProcessRecord()
         WriteObject(block);
     }
 
-    private LanguageScriptBlock? ConventionBlock(RunspaceContext context, ScriptBlock block, RunspaceScope scope)
+    private LanguageScriptBlock? ConventionBlock(RunspaceContext context, ScriptBlock? block, RunspaceScope scope)
     {
         if (block == null)
             return null;

src/PSRule/Common/LoggerExtensions.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT License.
 
+using System.Management.Automation;
 using PSRule.Definitions;
 using PSRule.Pipeline;
 using PSRule.Resources;
@@ -15,6 +16,7 @@ internal static class LoggerExtensions
 {
     private static readonly EventId PSR0004 = new(4, "PSR0004");
     private static readonly EventId PSR0005 = new(5, "PSR0005");
+    private static readonly EventId PSR0006 = new(6, "PSR0006");
 
     /// <summary>
     /// PSR0005: The {0} '{1}' is obsolete.
@@ -55,4 +57,27 @@ internal static void ErrorResourceUnresolved(this ILogger logger, ResourceKind k
             id
         );
     }
+
+    /// <summary>
+    /// PSR0006: Failed to deserialize the file '{0}': {1}
+    /// </summary>
+    internal static void ErrorReadFileFailed(this ILogger logger, string path, Exception innerException)
+    {
+        if (logger == null || !logger.IsEnabled(LogLevel.Error))
+            return;
+
+        logger.LogError
+        (
+            PSR0006,
+            new PipelineSerializationException(string.Format(
+                Thread.CurrentThread.CurrentCulture,
+                PSRuleResources.PSR0006,
+                path,
+                innerException.Message), path, innerException
+            ),
+            PSRuleResources.PSR0006,
+            path,
+            innerException.Message
+        );
+    }
 }

src/PSRule/Pipeline/Emitters/EmitterBuilder.cs

@@ -3,6 +3,7 @@
 
 using Microsoft.Extensions.DependencyInjection;
 using PSRule.Emitters;
+using PSRule.Runtime;
 
 namespace PSRule.Pipeline.Emitters;
 
@@ -18,10 +19,15 @@ public EmitterBuilder()
     {
         _EmitterTypes = new List<Type>(4);
         _Services = new ServiceCollection();
+        AddInternalServices();
         AddInternalEmitters();
     }
 
-    public void AddEmitter<T>() where T : IEmitter, new()
+    /// <summary>
+    /// Add an <see cref="IEmitter"/> implementation class.
+    /// </summary>
+    /// <typeparam name="T">An emitter type that implements <see cref="IEmitter"/>.</typeparam>
+    public void AddEmitter<T>() where T : class, IEmitter
     {
         _EmitterTypes.Add(typeof(T));
         _Services.AddTransient(typeof(T));
@@ -48,6 +54,18 @@ public EmitterCollection Build(IEmitterContext context)
         return new EmitterCollection(serviceProvider, [.. emitters], context);
     }
 
+    /// <summary>
+    /// Add the default services automatically added to the DI container.
+    /// </summary>
+    private void AddInternalServices()
+    {
+        _Services.AddSingleton<ILoggerFactory, LoggerFactory>();
+        _Services.AddSingleton(typeof(ILogger<>), typeof(Logger<>));
+    }
+
+    /// <summary>
+    /// Add the built-in emitters to the list of emitters for processing items.
+    /// </summary>
     private void AddInternalEmitters()
     {
         AddEmitter<YamlEmitter>();

src/PSRule/Pipeline/Emitters/JsonEmitter.cs

@@ -18,12 +18,14 @@ internal sealed class JsonEmitter : FileEmitter
     private const string EXTENSION_JSONC = ".jsonc";
     private const string EXTENSION_SARIF = ".sarif";
 
-    private readonly JsonSerializer _Deserializer;
+    private readonly ILogger<JsonEmitter> _Logger;
     private readonly JsonSerializerSettings _Settings;
+    private readonly JsonSerializer _Deserializer;
     private readonly HashSet<string> _Extensions;
 
-    public JsonEmitter()
+    public JsonEmitter(ILogger<JsonEmitter> logger)
     {
+        _Logger = logger;
         _Settings = new JsonSerializerSettings
         {
 
@@ -63,7 +65,7 @@ protected override bool VisitFile(IEmitterContext context, IFileStream stream)
         {
             if (stream.Info != null && !string.IsNullOrEmpty(stream.Info.Path))
             {
-                RunspaceContext.CurrentThread.Writer.ErrorReadFileFailed(stream.Info.Path, ex);
+                _Logger.ErrorReadFileFailed(stream.Info.Path, ex);
             }
             throw;
         }

src/PSRule/Pipeline/Emitters/YamlEmitter.cs

@@ -20,11 +20,13 @@ internal sealed class YamlEmitter : FileEmitter
     private const string EXTENSION_YAML = ".yaml";
     private const string EXTENSION_YML = ".yml";
 
+    private readonly ILogger<YamlEmitter> _Logger;
     private readonly PSObjectYamlTypeConverter _TypeConverter;
     private readonly IDeserializer _Deserializer;
 
-    public YamlEmitter()
+    public YamlEmitter(ILogger<YamlEmitter> logger)
     {
+        _Logger = logger;
         _TypeConverter = new PSObjectYamlTypeConverter();
         _Deserializer = GetDeserializer();
     }
@@ -63,7 +65,7 @@ protected override bool VisitFile(IEmitterContext context, IFileStream stream)
         {
             if (stream.Info != null && !string.IsNullOrEmpty(stream.Info.Path))
             {
-                RunspaceContext.CurrentThread.Writer.ErrorReadFileFailed(stream.Info.Path, ex);
+                _Logger.ErrorReadFileFailed(stream.Info.Path, ex);
             }
             throw;
         }

src/PSRule/Resources/PSRuleResources.resx

@@ -415,4 +415,7 @@
   <data name="PSR0004" xml:space="preserve">
     <value>PSR0004: The specified {0} resource '{1}' is not known.</value>
   </data>
+  <data name="PSR0006" xml:space="preserve">
+    <value>PSR0006: Failed to deserialize the file '{0}': {1}</value>
+  </data>
 </root>

src/PSRule/Runtime/LoggerFactory.cs

@@ -0,0 +1,15 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+namespace PSRule.Runtime;
+
+/// <summary>
+/// Implements creating a logger for a specific category.
+/// </summary>
+internal sealed class LoggerFactory : ILoggerFactory
+{
+    public ILogger Create(string categoryName)
+    {
+        return RunspaceContext.CurrentThread == null ? RunspaceContext.CurrentThread : NullLogger.Instance;
+    }
+}

tests/PSRule.Tests/ConventionTests.cs

@@ -17,8 +17,8 @@ public void WithConventions()
     {
         var testObject1 = new TestObject { Name = "TestObject1" };
         var option = GetOption();
-        option.Rule.Include = new string[] { "ConventionTest" };
-        option.Convention.Include = new string[] { "Convention1" };
+        option.Rule.Include = ["ConventionTest"];
+        option.Convention.Include = ["Convention1"];
         var builder = PipelineBuilder.Invoke(GetSource(), option, null);
         var pipeline = builder.Build();
 
@@ -33,10 +33,10 @@ public void ConventionOrder()
     {
         var testObject1 = new TestObject { Name = "TestObject1" };
         var option = GetOption();
-        option.Rule.Include = new string[] { "ConventionTest" };
+        option.Rule.Include = ["ConventionTest"];
 
         // Order 1
-        option.Convention.Include = new string[] { "Convention1", "Convention2" };
+        option.Convention.Include = ["Convention1", "Convention2"];
         var writer = new TestWriter(option);
         var builder = PipelineBuilder.Invoke(GetSource(), option, null);
         var pipeline = builder.Build(writer);
@@ -48,7 +48,7 @@ public void ConventionOrder()
         Assert.Equal(110, actual2);
 
         // Order 2
-        option.Convention.Include = new string[] { "Convention2", "Convention1" };
+        option.Convention.Include = ["Convention2", "Convention1"];
         writer = new TestWriter(option);
         builder = PipelineBuilder.Invoke(GetSource(), option, null);
         pipeline = builder.Build(writer);
@@ -68,8 +68,8 @@ public void WithLocalizedData()
     {
         var testObject1 = new TestObject { Name = "TestObject1" };
         var option = GetOption();
-        option.Rule.Include = new string[] { "WithLocalizedDataPrecondition" };
-        option.Convention.Include = new string[] { "Convention.WithLocalizedData" };
+        option.Rule.Include = ["WithLocalizedDataPrecondition"];
+        option.Convention.Include = ["Convention.WithLocalizedData"];
         var writer = new TestWriter(option);
         var builder = PipelineBuilder.Invoke(GetSource(), option, null);
         var pipeline = builder.Build(writer);