Compile property accessor (#98)

src/Destructurama.Attributed.Tests/AttributedDestructuringTests.cs

@@ -9,6 +9,28 @@ namespace Destructurama.Attributed.Tests;
 [TestFixture]
 public class AttributedDestructuringTests
 {
+ [Test]
+ public void Throwing_Accessor_Should_Be_Handled()
+ {
+ // Setup
+ LogEvent evt = null!;
+
+ var log = new LoggerConfiguration()
+ .Destructure.UsingAttributes()
+ .WriteTo.Sink(new DelegatingSink(e => evt = e))
+ .CreateLogger();
+ var obj = new ClassWithThrowingAccessor();
+
+ // Execute
+ log.Information("Here is {@Customized}", obj);
+
+ // Verify
+ var sv = (StructureValue)evt.Properties["Customized"];
+ sv.Properties.Count.ShouldBe(1);
+ sv.Properties[0].Name.ShouldBe("BadProperty");
+ sv.Properties[0].Value.ShouldBeOfType<ScalarValue>().Value.ShouldBe("***");
+ }
+
  [Test]
  public void AttributesAreConsultedWhenDestructuring()
  {
@@ -51,6 +73,12 @@ public void AttributesAreConsultedWhenDestructuring()
  str.Contains("This is a password").ShouldBeFalse();
  }
 
+ public class ClassWithThrowingAccessor
+ {
+ [LogMasked]
+ public string? BadProperty => throw new FormatException("oops");
+ }
+
  [LogAsScalar]
  public class ImmutableScalar
  {

src/Destructurama.Attributed/Attributed/AttributedDestructuringPolicy.cs

@@ -15,6 +15,7 @@
 using System.Collections;
 using System.Collections.Concurrent;
 using System.Diagnostics.CodeAnalysis;
+using System.Linq.Expressions;
 using System.Reflection;
 using Destructurama.Util;
 using Serilog.Core;
@@ -53,10 +54,9 @@ private CacheEntry CreateCacheEntry(Type type)
  return new(classDestructurer.CreateLogEventPropertyValue);
 
  var properties = type.GetPropertiesRecursive().ToList();
- if (!_options.IgnoreNullProperties
- && properties.All(pi =>
- pi.GetCustomAttribute<IPropertyDestructuringAttribute>() == null
- && pi.GetCustomAttribute<IPropertyOptionalIgnoreAttribute>() == null))
+ if (!_options.IgnoreNullProperties && properties.All(pi =>
+ pi.GetCustomAttribute<IPropertyDestructuringAttribute>() == null
+ && pi.GetCustomAttribute<IPropertyOptionalIgnoreAttribute>() == null))
  {
  return CacheEntry.Ignore;
  }
@@ -74,21 +74,40 @@ private CacheEntry CreateCacheEntry(Type type)
  if (_options.IgnoreNullProperties && !optionalIgnoreAttributes.Any() && !destructuringAttributes.Any() && typeof(IEnumerable).IsAssignableFrom(type))
  return CacheEntry.Ignore;
 
- return new CacheEntry((o, f) => MakeStructure(o, properties, optionalIgnoreAttributes, destructuringAttributes, f, type));
+ var propertiesWithAccessors = properties.Select(p => (p, Compile(p))).ToList();
+ return new CacheEntry((o, f) => MakeStructure(o, propertiesWithAccessors, optionalIgnoreAttributes, destructuringAttributes, f, type));
+
+ static Func<object, object> Compile(PropertyInfo property)
+ {
+ var objParameterExpr = Expression.Parameter(typeof(object), "instance");
+ var instanceExpr = Expression.Convert(objParameterExpr, property.DeclaringType);
+ var propertyExpr = Expression.Property(instanceExpr, property);
+ var propertyObjExpr = Expression.Convert(propertyExpr, typeof(object));
+ return Expression.Lambda<Func<object, object>>(propertyObjExpr, objParameterExpr).Compile();
+ }
  }
 
  private LogEventPropertyValue MakeStructure(
  object o,
- IEnumerable<PropertyInfo> loggedProperties,
- IDictionary<PropertyInfo, IPropertyOptionalIgnoreAttribute> optionalIgnoreAttributes,
- IDictionary<PropertyInfo, IPropertyDestructuringAttribute> destructuringAttributes,
+ List<(PropertyInfo Property, Func<object, object> Accessor)> loggedProperties,
+ Dictionary<PropertyInfo, IPropertyOptionalIgnoreAttribute> optionalIgnoreAttributes,
+ Dictionary<PropertyInfo, IPropertyDestructuringAttribute> destructuringAttributes,
  ILogEventPropertyValueFactory propertyValueFactory,
  Type type)
  {
  var structureProperties = new List<LogEventProperty>();
- foreach (var pi in loggedProperties)
+ foreach (var (pi, accessor) in loggedProperties)
  {
- var propValue = SafeGetPropValue(o, pi);
+ object propValue;
+ try
+ {
+ propValue = accessor(o);
+ }
+ catch (Exception ex)
+ {
+ SelfLog.WriteLine("The property accessor {0} threw exception {1}", pi, ex);
+ propValue = $"The property accessor threw an exception: {ex.GetType().Name}";
+ }
 
  if (optionalIgnoreAttributes.TryGetValue(pi, out var optionalIgnoreAttribute) && optionalIgnoreAttribute.ShouldPropertyBeIgnored(pi.Name, propValue, pi.PropertyType))
  continue;
@@ -110,19 +129,6 @@ private LogEventPropertyValue MakeStructure(
  return new StructureValue(structureProperties, type.Name);
  }
 
- private static object SafeGetPropValue(object o, PropertyInfo pi)
- {
- try
- {
- return pi.GetValue(o);
- }
- catch (TargetInvocationException ex)
- {
- SelfLog.WriteLine("The property accessor {0} threw exception {1}", pi, ex);
- return $"The property accessor threw an exception: {ex.InnerException!.GetType().Name}";
- }
- }
-
  internal static void Clear()
  {
  _cache.Clear();