Allow specifying a PropertyName for custom columns, rather than requiring

Author: rocknet

src/Serilog.Sinks.MSSqlServer/Configuration/Implementations/System.Configuration/ColumnConfig.cs

@@ -40,6 +40,13 @@ public virtual string ColumnName
             set { this[nameof(ColumnName)] = value; }
         }
 
+        [ConfigurationProperty("PropertyName")]
+        public virtual string PropertyName
+        {
+            get { return (string)this["PropertyName"]; }
+            set { this["PropertyName"] = value; }
+        }
+
         [ConfigurationProperty("DataType")]
         public string DataType
         {
@@ -75,6 +82,8 @@ internal SqlColumn AsSqlColumn()
             // inheritors can override IsRequired; config might not change the names of Standard Columns
             SetProperty.IfProvidedNotEmpty<string>(this, nameof(ColumnName), (val) => sqlColumn.ColumnName = val);
 
+            SetProperty.IfProvidedNotEmpty<string>(this, nameof(PropertyName), (val) => sqlColumn.PropertyName = val);
+
             SetProperty.IfProvidedNotEmpty<string>(this, nameof(DataType), (val) => sqlColumn.SetDataTypeFromConfigString(val));
 
             SetProperty.IfProvided<int>(this, nameof(DataLength), (val) => sqlColumn.DataLength = val);

src/Serilog.Sinks.MSSqlServer/Sinks/MSSqlServer/MSSqlServerSinkTraits.cs

@@ -229,10 +229,14 @@ private IEnumerable<KeyValuePair<string, object>> ConvertPropertiesToColumn(IRea
         {
             foreach (var property in properties)
             {
-                if (!EventTable.Columns.Contains(property.Key) || StandardColumnNames.Contains(property.Key))
+                var additionalColumn = columnOptions
+                    .AdditionalColumns
+                    .FirstOrDefault(ac => ac.PropertyName == property.Key);
+
+                if (additionalColumn == null || standardColumnNames.Contains(property.Key))
                     continue;
 
-                var columnName = property.Key;
+                var columnName = additionalColumn.ColumnName;
                 var columnType = EventTable.Columns[columnName].DataType;
 
                 if (!(property.Value is ScalarValue scalarValue))

src/Serilog.Sinks.MSSqlServer/Sinks/MSSqlServer/SqlColumn.cs

@@ -10,6 +10,7 @@ public class SqlColumn
     {
         private SqlDbType _dataType = SqlDbType.VarChar; // backwards-compatibility default
         private string _columnName = string.Empty;
+        private string _propertyName;
 
         /// <summary>
         /// Default constructor.
@@ -95,6 +96,16 @@ public SqlDbType DataType
         /// </summary>
         public bool NonClusteredIndex { get; set; } = false;
 
+        /// <summary>
+        /// The name of the Serilog property to use as the value when filling the DataTable.
+        /// If not specified, the ColumnName and PropertyName are the same.
+        /// </summary>
+        public string PropertyName
+        {
+            get => _propertyName ?? ColumnName;
+            set => _propertyName = value;
+        }
+
         // Set by the constructors of the Standard Column classes that inherit from this;
         // allows Standard Columns and user-defined columns to coexist but remain identifiable
         // and allows casting back to the Standard Column without a lot of switch gymnastics.
@@ -128,7 +139,7 @@ internal virtual DataColumn AsDataColumn()
         }
 
         /// <summary>
-        /// Configuration accepts DataType as a simple string ("nvarchar" for example) for ease-of-use. 
+        /// Configuration accepts DataType as a simple string ("nvarchar" for example) for ease-of-use.
         /// This converts to SqlDbType and stores it into the DataType property.
         /// </summary>
         internal void SetDataTypeFromConfigString(string requestedSqlType)