Add ability to export attributes corresponding to Logrecord.EventId

src/OpenTelemetry.Exporter.OpenTelemetryProtocol/CHANGELOG.md

@@ -19,6 +19,13 @@ attributes will be exported when
 variable will be set to `true`.
 ([#4892](https://github.com/open-telemetry/opentelemetry-dotnet/pull/4892))
 
+* Added ability to export attributes corresponding to `LogRecord.EventId` as
+`event.id` and `event.name` and `LogRecord.CategoryName` as
+`dotnet.ilogger.category`. These attributes will be exported when
+`OTEL_DOTNET_EXPERIMENTAL_OTLP_EMIT_CATEGORY_AND_EVENT_LOG_ATTRIBUTES` will be
+set to `true`.
+([#4925](https://github.com/open-telemetry/opentelemetry-dotnet/pull/4925))
+
 ## 1.6.0
 
 Released 2023-Sep-05

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

@@ -25,6 +25,8 @@ internal sealed class ExperimentalOptions
 {
     public const string EMITLOGEXCEPTIONATTRIBUTES = "OTEL_DOTNET_EXPERIMENTAL_OTLP_EMIT_EXCEPTION_LOG_ATTRIBUTES";
 
+    public const string EMITCATEGORYANDEVENTATTRIBUTES = "OTEL_DOTNET_EXPERIMENTAL_OTLP_EMIT_CATEGORY_AND_EVENT_LOG_ATTRIBUTES";
+
     public ExperimentalOptions()
         : this(new ConfigurationBuilder().AddEnvironmentVariables().Build())
     {
@@ -36,10 +38,20 @@ public ExperimentalOptions(IConfiguration configuration)
         {
             this.EmitLogExceptionAttributes = emitLogExceptionAttributes;
         }
+
+        if (configuration.TryGetBoolValue(EMITCATEGORYANDEVENTATTRIBUTES, out var emitLogEventAndCategoryAttributes))
+        {
+            this.EmitLogEventAndCategoryAttributes = emitLogEventAndCategoryAttributes;
+        }
     }
 
     /// <summary>
     /// Gets or sets a value indicating whether log exception attributes should be exported.
     /// </summary>
     public bool EmitLogExceptionAttributes { get; set; } = false;
+
+    /// <summary>
+    /// Gets or sets a value indicating whether log event and category attributes should be exported.
+    /// </summary>
+    public bool EmitLogEventAndCategoryAttributes { get; set; } = false;
 }

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

@@ -91,33 +91,28 @@ internal OtlpLogs.LogRecord ToOtlpLog(LogRecord logRecord)
             var attributeValueLengthLimit = this.sdkLimitOptions.LogRecordAttributeValueLengthLimit;
             var attributeCountLimit = this.sdkLimitOptions.LogRecordAttributeCountLimit ?? int.MaxValue;
 
-            /*
-            // Removing this temporarily for stable release
-            // https://github.com/open-telemetry/opentelemetry-dotnet/issues/4776
-            // https://github.com/open-telemetry/opentelemetry-dotnet/issues/3491
-            // First add the generic attributes like Category, EventId and Exception,
-            // so they are less likely being dropped because of AttributeCountLimit.
-
-            if (!string.IsNullOrEmpty(logRecord.CategoryName))
+            if (this.experimentalOptions.EmitLogEventAndCategoryAttributes)
             {
-                // TODO:
-                // 1. Track the following issue, and map CategoryName to Name
-                // if it makes it to log data model.
-                // https://github.com/open-telemetry/opentelemetry-specification/issues/2398
-                // 2. Confirm if this name for attribute is good.
-                otlpLogRecord.AddStringAttribute("dotnet.ilogger.category", logRecord.CategoryName, attributeValueLengthLimit, attributeCountLimit);
-            }
+                if (!string.IsNullOrEmpty(logRecord.CategoryName))
+                {
+                    // TODO:
+                    // 1. Track the following issue, and map CategoryName to Name
+                    // if it makes it to log data model.
+                    // https://github.com/open-telemetry/opentelemetry-specification/issues/2398
+                    // 2. Confirm if this name for attribute is good.
+                    AddStringAttribute(otlpLogRecord, "dotnet.ilogger.category", logRecord.CategoryName, attributeValueLengthLimit, attributeCountLimit);
+                }
 
-            if (logRecord.EventId.Id != default)
-            {
-                otlpLogRecord.AddIntAttribute(nameof(logRecord.EventId.Id), logRecord.EventId.Id, attributeCountLimit);
-            }
+                if (logRecord.EventId.Id != default)
+                {
+                    AddIntAttribute(otlpLogRecord, "event.id", logRecord.EventId.Id, attributeCountLimit);
+                }
 
-            if (!string.IsNullOrEmpty(logRecord.EventId.Name))
-            {
-                otlpLogRecord.AddStringAttribute(nameof(logRecord.EventId.Name), logRecord.EventId.Name, attributeValueLengthLimit, attributeCountLimit);
+                if (!string.IsNullOrEmpty(logRecord.EventId.Name))
+                {
+                    AddStringAttribute(otlpLogRecord, "event.name", logRecord.EventId.Name, attributeValueLengthLimit, attributeCountLimit);
+                }
             }
-            */
 
             if (this.experimentalOptions.EmitLogExceptionAttributes && logRecord.Exception != null)
             {

src/OpenTelemetry.Exporter.OpenTelemetryProtocol/README.md

@@ -229,6 +229,11 @@ When set to `true`, it enables export of attributes corresponding to
 `exception.stacktrace` are defined in
 [specification](https://github.com/open-telemetry/semantic-conventions/blob/main/docs/exceptions/exceptions-logs.md#attributes).
 
+* `OTEL_DOTNET_EXPERIMENTAL_OTLP_EMIT_CATEGORY_AND_EVENT_LOG_ATTRIBUTES`
+
+When set to `true`, it enables export of `LogRecord.EventId` as `event.id` and
+`event.name` and `LogRecord.CategoryName` as `dotnet.ilogger.category`.
+
 ## Configure HttpClient
 
 The `HttpClientFactory` option is provided on `OtlpExporterOptions` for users

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

@@ -209,9 +209,11 @@ public void OtlpLogRecordTestWhenStateValuesArePopulated()
         Assert.Equal("Hello from {name} {price}.", attribute.Value.StringValue);
     }
 
-    /*
-    [Fact]
-    public void CheckToOtlpLogRecordLoggerCategory()
+    [Theory]
+    [InlineData("true")]
+    [InlineData("false")]
+    [InlineData(null)]
+    public void CheckToOtlpLogRecordLoggerCategory(string emitLogEventAndCategoryAttributes)
     {
         var logRecords = new List<LogRecord>();
         using var loggerFactory = LoggerFactory.Create(builder =>
@@ -227,27 +229,46 @@ public void CheckToOtlpLogRecordLoggerCategory()
         Assert.Single(logRecords);
 
         var logRecord = logRecords[0];
-        var otlpLogRecord = logRecord.ToOtlpLog(DefaultSdkLimitOptions, new());
-        Assert.NotNull(otlpLogRecord);
-        Assert.Single(otlpLogRecord.Attributes);
 
-        var attribute = otlpLogRecord.Attributes[0];
-        Assert.Equal("dotnet.ilogger.category", attribute.Key);
-        Assert.Equal("CategoryA", attribute.Value.StringValue);
+        var configuration = new ConfigurationBuilder()
+           .AddInMemoryCollection(new Dictionary<string, string> { [ExperimentalOptions.EMITCATEGORYANDEVENTATTRIBUTES] = emitLogEventAndCategoryAttributes })
+           .Build();
+
+        var otlpLogRecordTransformer = new OtlpLogRecordTransformer(DefaultSdkLimitOptions, new(configuration));
+
+        var otlpLogRecord = otlpLogRecordTransformer.ToOtlpLog(logRecord);
+
+        if (emitLogEventAndCategoryAttributes == "true")
+        {
+            Assert.NotNull(otlpLogRecord);
+            Assert.Single(otlpLogRecord.Attributes);
+
+            var attribute = otlpLogRecord.Attributes[0];
+            Assert.Equal("dotnet.ilogger.category", attribute.Key);
+            Assert.Equal("CategoryA", attribute.Value.StringValue);
+        }
+        else
+        {
+            Assert.NotNull(otlpLogRecord);
+            Assert.Empty(otlpLogRecord.Attributes);
+        }
 
         logRecords.Clear();
         var logger2 = loggerFactory.CreateLogger(string.Empty);
         logger2.LogInformation("Hello");
         Assert.Single(logRecords);
 
         logRecord = logRecords[0];
-        otlpLogRecord = logRecord.ToOtlpLog(DefaultSdkLimitOptions, new());
+        otlpLogRecord = otlpLogRecordTransformer.ToOtlpLog(logRecord);
         Assert.NotNull(otlpLogRecord);
         Assert.Empty(otlpLogRecord.Attributes);
     }
 
-    [Fact]
-    public void CheckToOtlpLogRecordEventId()
+    [Theory]
+    [InlineData("true")]
+    [InlineData("false")]
+    [InlineData(null)]
+    public void CheckToOtlpLogRecordEventId(string emitLogEventAndCategoryAttributes)
     {
         var logRecords = new List<LogRecord>();
         using var loggerFactory = LoggerFactory.Create(builder =>
@@ -264,37 +285,56 @@ public void CheckToOtlpLogRecordEventId()
         logger.LogInformation(new EventId(10, null), "Hello from {name} {price}.", "tomato", 2.99);
         Assert.Single(logRecords);
 
+        var configuration = new ConfigurationBuilder()
+          .AddInMemoryCollection(new Dictionary<string, string> { [ExperimentalOptions.EMITCATEGORYANDEVENTATTRIBUTES] = emitLogEventAndCategoryAttributes })
+          .Build();
+
+        var otlpLogRecordTransformer = new OtlpLogRecordTransformer(DefaultSdkLimitOptions, new(configuration));
+
         var logRecord = logRecords[0];
-        var otlpLogRecord = logRecord.ToOtlpLog(DefaultSdkLimitOptions, new());
+
+        var otlpLogRecord = otlpLogRecordTransformer.ToOtlpLog(logRecord);
 
         Assert.NotNull(otlpLogRecord);
         Assert.Equal("Hello from tomato 2.99.", otlpLogRecord.Body.StringValue);
 
-        var otlpLogRecordAttributes = otlpLogRecord.Attributes.ToString();
-
         // Event
-        Assert.Contains("Id", otlpLogRecordAttributes);
-        Assert.Contains("10", otlpLogRecordAttributes);
+        var otlpLogRecordAttributes = otlpLogRecord.Attributes.ToString();
+        if (emitLogEventAndCategoryAttributes == "true")
+        {
+            Assert.Contains("event.id", otlpLogRecordAttributes);
+            Assert.Contains("10", otlpLogRecordAttributes);
+        }
+        else
+        {
+            Assert.DoesNotContain("event.id", otlpLogRecordAttributes);
+        }
 
         logRecords.Clear();
 
         logger.LogInformation(new EventId(10, "MyEvent10"), "Hello from {name} {price}.", "tomato", 2.99);
         Assert.Single(logRecords);
 
         logRecord = logRecords[0];
-        otlpLogRecord = logRecord.ToOtlpLog(DefaultSdkLimitOptions, new());
+        otlpLogRecord = otlpLogRecordTransformer.ToOtlpLog(logRecord);
         Assert.NotNull(otlpLogRecord);
         Assert.Equal("Hello from tomato 2.99.", otlpLogRecord.Body.StringValue);
 
-        otlpLogRecordAttributes = otlpLogRecord.Attributes.ToString();
-
         // Event
-        Assert.Contains("Id", otlpLogRecordAttributes);
-        Assert.Contains("10", otlpLogRecordAttributes);
-        Assert.Contains("Name", otlpLogRecordAttributes);
-        Assert.Contains("MyEvent10", otlpLogRecordAttributes);
+        otlpLogRecordAttributes = otlpLogRecord.Attributes.ToString();
+        if (emitLogEventAndCategoryAttributes == "true")
+        {
+            Assert.Contains("event.id", otlpLogRecordAttributes);
+            Assert.Contains("10", otlpLogRecordAttributes);
+            Assert.Contains("event.name", otlpLogRecordAttributes);
+            Assert.Contains("MyEvent10", otlpLogRecordAttributes);
+        }
+        else
+        {
+            Assert.DoesNotContain("event.id", otlpLogRecordAttributes);
+            Assert.DoesNotContain("event.name", otlpLogRecordAttributes);
+        }
     }
-    */
 
     [Fact]
     public void CheckToOtlpLogRecordTimestamps()