Add option to set template as body

Author: danelson

src/Serilog.Sinks.OpenTelemetry/Sinks/OpenTelemetry/IncludedData.cs

@@ -56,4 +56,20 @@ public enum IncludedData
     /// means <c>service.name</c> if not supplied, along with the <c>telemetry.sdk.*</c> group of attributes.
     /// </summary>
     SpecRequiredResourceAttributes = 16,
+
+    /// <summary>
+    /// Include the log event's message template in the OTLP <c>body</c> instead of the rendered messsage. For 
+    /// example, the string <c>Hello {Name}!</c>.
+    /// </summary>
+    /// <remarks>
+    /// Note: It is often desirable to remove <see cref="IncludedData.MessageTemplateTextAttribute"/> when using
+    /// <see cref="IncludedData.TemplateBody"/> but otherwise use defaults.
+    /// <code>
+    /// .WriteTo.OpenTelemetry(options =>
+    /// {
+    ///     options.IncludedData = (options.IncludedData | IncludedData.TemplateBody) &amp; ~IncludedData.MessageTemplateTextAttribute;
+    /// })
+    /// </code>
+    /// </remarks>
+    TemplateBody = 32
 }

src/Serilog.Sinks.OpenTelemetry/Sinks/OpenTelemetry/LogRecordBuilder.cs

@@ -28,24 +28,33 @@ public static LogRecord ToLogRecord(LogEvent logEvent, IFormatProvider? formatPr
 
         ProcessProperties(logRecord, logEvent);
         ProcessTimestamp(logRecord, logEvent);
-        ProcessMessage(logRecord, logEvent, formatProvider);
+        ProcessMessage(logRecord, logEvent, includedFields, formatProvider);
         ProcessLevel(logRecord, logEvent);
         ProcessException(logRecord, logEvent);
         ProcessIncludedFields(logRecord, logEvent, includedFields, activityContextCollector);
 
         return logRecord;
     }
 
-    public static void ProcessMessage(LogRecord logRecord, LogEvent logEvent, IFormatProvider? formatProvider)
+    public static void ProcessMessage(LogRecord logRecord, LogEvent logEvent, IncludedData includedFields, IFormatProvider? formatProvider)
     {
         var renderedMessage = CleanMessageTemplateFormatter.Format(logEvent.MessageTemplate, logEvent.Properties, formatProvider);
-        if (renderedMessage.Trim() != "")
+
+        if (!includedFields.HasFlag(IncludedData.TemplateBody) && renderedMessage.Trim() != "")
         {
             logRecord.Body = new AnyValue
             {
                 StringValue = renderedMessage
             };
         }
+
+        if (includedFields.HasFlag(IncludedData.TemplateBody) && logEvent.MessageTemplate.Text.Trim() != "")
+        {
+            logRecord.Body = new AnyValue
+            {
+                StringValue = logEvent.MessageTemplate.Text
+            };
+        }
     }
 
     public static void ProcessLevel(LogRecord logRecord, LogEvent logEvent)

src/Serilog.Sinks.OpenTelemetry/Sinks/OpenTelemetry/OpenTelemetrySinkOptions.cs

@@ -26,7 +26,7 @@ public class OpenTelemetrySinkOptions
     internal const string DefaultEndpoint = "http://localhost:4317";
     internal const OtlpProtocol DefaultProtocol = OtlpProtocol.Grpc;
 
-    const IncludedData DefaultIncludedData = IncludedData.MessageTemplateTextAttribute |
+    internal const IncludedData DefaultIncludedData = IncludedData.MessageTemplateTextAttribute |
                                              IncludedData.TraceIdField | IncludedData.SpanIdField |
                                              IncludedData.SpecRequiredResourceAttributes;
 

test/Serilog.Sinks.OpenTelemetry.Tests/LogRecordBuilderTests.cs

@@ -29,14 +29,14 @@ public void TestProcessMessage()
     {
         var logRecord = new LogRecord();
 
-        LogRecordBuilder.ProcessMessage(logRecord, Some.SerilogEvent(messageTemplate: ""), null);
+        LogRecordBuilder.ProcessMessage(logRecord, Some.SerilogEvent(messageTemplate: ""), OpenTelemetrySinkOptions.DefaultIncludedData, null);
         Assert.Null(logRecord.Body);
 
-        LogRecordBuilder.ProcessMessage(logRecord, Some.SerilogEvent(messageTemplate: "\t\f "), null);
+        LogRecordBuilder.ProcessMessage(logRecord, Some.SerilogEvent(messageTemplate: "\t\f "), OpenTelemetrySinkOptions.DefaultIncludedData, null);
         Assert.Null(logRecord.Body);
 
         const string message = "log message";
-        LogRecordBuilder.ProcessMessage(logRecord, Some.SerilogEvent(messageTemplate: message), null);
+        LogRecordBuilder.ProcessMessage(logRecord, Some.SerilogEvent(messageTemplate: message), OpenTelemetrySinkOptions.DefaultIncludedData, null);
         Assert.NotNull(logRecord.Body);
         Assert.Equal(message, logRecord.Body.StringValue);
     }
@@ -180,4 +180,12 @@ public void IncludeTraceIdAndSpanId()
         Assert.Equal(logRecord.TraceId, PrimitiveConversions.ToOpenTelemetryTraceId(Activity.Current.TraceId.ToHexString()));
         Assert.Equal(logRecord.SpanId, PrimitiveConversions.ToOpenTelemetrySpanId(Activity.Current.SpanId.ToHexString()));
     }
+
+    [Fact]
+    public void IncludeTemplateBody()
+    {
+        var logRecord = LogRecordBuilder.ToLogRecord(Some.SerilogEvent(), null, IncludedData.TemplateBody, new());
+        Assert.NotNull(logRecord.Body);
+        Assert.Equal(Some.TestMessageTemplate, logRecord.Body.StringValue);
+    }
 }

test/Serilog.Sinks.OpenTelemetry.Tests/PublicApiVisibilityTests.approved.txt

@@ -24,6 +24,7 @@ namespace Serilog.Sinks.OpenTelemetry
         TraceIdField = 4,
         SpanIdField = 8,
         SpecRequiredResourceAttributes = 16,
+        TemplateBody = 32,
     }
     public class OpenTelemetrySinkOptions
     {