OTLP LogExporter to special case {OriginalFormat} to populate body

src/OpenTelemetry.Exporter.OpenTelemetryProtocol/CHANGELOG.md

@@ -2,9 +2,12 @@
 
 ## Unreleased
 
-* LogExporter to correcly map Severity to OTLP.
+* LogExporter to correctly map Severity to OTLP.
   ([#3177](https://github.com/open-telemetry/opentelemetry-dotnet/pull/3177))
 
+* LogExporter to special case {OriginalFormat} to populate
+  Body. ([#3182](https://github.com/open-telemetry/opentelemetry-dotnet/pull/3182))
+
 ## 1.2.0-rc5
 
 Released 2022-Apr-12

src/OpenTelemetry.Exporter.OpenTelemetryProtocol/Implementation/LogRecordExtensions.cs

@@ -76,17 +76,26 @@ internal static OtlpLogs.LogRecord ToOtlpLog(this LogRecord logRecord)
 
                 // TODO: Add logRecord.CategoryName as an attribute
 
+                bool bodyPopulatedFromFormattedMessage = false;
                 if (logRecord.FormattedMessage != null)
                 {
                     otlpLogRecord.Body = new OtlpCommon.AnyValue { StringValue = logRecord.FormattedMessage };
+                    bodyPopulatedFromFormattedMessage = true;
                 }
 
                 if (logRecord.StateValues != null)
                 {
                     foreach (var stateValue in logRecord.StateValues)
                     {
-                        var otlpAttribute = stateValue.ToOtlpAttribute();
-                        otlpLogRecord.Attributes.Add(otlpAttribute);
+                        if (stateValue.Key.Equals("{OriginalFormat}") && !bodyPopulatedFromFormattedMessage)
+                        {
+                            otlpLogRecord.Body = new OtlpCommon.AnyValue { StringValue = stateValue.Value as string };
+                        }
+                        else
+                        {
+                            var otlpAttribute = stateValue.ToOtlpAttribute();
+                            otlpLogRecord.Attributes.Add(otlpAttribute);
+                        }
                     }
                 }
 

test/OpenTelemetry.Exporter.OpenTelemetryProtocol.Tests/OtlpLogExporterTests.cs

@@ -225,28 +225,82 @@ public void CheckToOtlpLogRecordSeverityLevelAndText(LogLevel logLevel)
             }
         }
 
-        [Fact]
-        public void CheckToOtlpLogRecordFormattedMessage()
+        [Theory]
+        [InlineData(true)]
+        [InlineData(false)]
+        public void CheckToOtlpLogRecordBodyIsPopulated(bool includeFormattedMessage)
         {
             var logRecords = new List<LogRecord>();
             using var loggerFactory = LoggerFactory.Create(builder =>
             {
                 builder.AddOpenTelemetry(options =>
                 {
                     options.AddInMemoryExporter(logRecords);
-                    options.IncludeFormattedMessage = true;
+                    options.IncludeFormattedMessage = includeFormattedMessage;
+                    options.ParseStateValues = true;
                 });
             });
 
             var logger = loggerFactory.CreateLogger("OtlpLogExporterTests");
+
+            // Scenario 1 - Using ExtensionMethods on ILogger.Log
             logger.LogInformation("OpenTelemetry {Greeting} {Subject}!", "Hello", "World");
             Assert.Single(logRecords);
 
             var logRecord = logRecords[0];
             var otlpLogRecord = logRecord.ToOtlpLog();
 
             Assert.NotNull(otlpLogRecord);
-            Assert.Equal(logRecord.FormattedMessage, otlpLogRecord.Body.StringValue);
+            if (includeFormattedMessage)
+            {
+                Assert.Equal(logRecord.FormattedMessage, otlpLogRecord.Body.StringValue);
+            }
+            else
+            {
+                Assert.Equal("OpenTelemetry {Greeting} {Subject}!", otlpLogRecord.Body.StringValue);
+            }
+
+            logRecords.Clear();
+
+            // Scenario 2 - Using the raw ILogger.Log Method
+            logger.Log(LogLevel.Information, default, "state", exception: null, (st, ex) => "Formatted Message");
+            Assert.Single(logRecords);
+
+            logRecord = logRecords[0];
+            otlpLogRecord = logRecord.ToOtlpLog();
+
+            Assert.NotNull(otlpLogRecord);
+            if (includeFormattedMessage)
+            {
+                Assert.Equal(logRecord.FormattedMessage, otlpLogRecord.Body.StringValue);
+            }
+            else
+            {
+                Assert.Null(otlpLogRecord.Body);
+            }
+
+            logRecords.Clear();
+
+            // Scenario 3 - Using the raw ILogger.Log Method, but with null
+            // formatter.
+            logger.Log(LogLevel.Information, default, "state", exception: null, formatter: null);
+            Assert.Single(logRecords);
+
+            logRecord = logRecords[0];
+            otlpLogRecord = logRecord.ToOtlpLog();
+
+            Assert.NotNull(otlpLogRecord);
+
+            // There is no formatter, so no way to populate Body.
+            // Exporter won't even attempt to do ToString() on State.
+            if (includeFormattedMessage)
+            {
+                Assert.Null(otlpLogRecord.Body);
+            }
+            else
+            {
+                Assert.Null(otlpLogRecord.Body);
+            }
         }
 
         [Fact]