[otlp] Update changelog / Remove OtlpExporter resource modification code (#6015)

Co-authored-by: Mikel Blanchard <mblanchard@macrosssoftware.com>

src/OpenTelemetry.Exporter.OpenTelemetryProtocol/CHANGELOG.md

@@ -7,6 +7,32 @@ Notes](../../RELEASENOTES.md).
 
 ## Unreleased
 
+* Removed the following package references:
+
+  * `Google.Protobuf`
+  * `Grpc`
+  * `Grpc.Net.Client`
+
+  These changes were made to streamline dependencies and reduce the footprint of
+  the exporter.
+  ([#6005](https://github.com/open-telemetry/opentelemetry-dotnet/pull/6005))
+
+* Switched from using the `Google.Protobuf` library for serialization to a
+  custom manual implementation of protobuf serialization.
+  ([#6005](https://github.com/open-telemetry/opentelemetry-dotnet/pull/6005))
+
+* Fixed an issue where a `service.name` was added to the resource if it was
+  missing. The exporter now respects the resource data provided by the SDK
+  without modifications.
+  ([#6015](https://github.com/open-telemetry/opentelemetry-dotnet/pull/6015))
+
+* Removed the peer service resolver, which was based on earlier experimental
+  semantic conventions that are not part of the stable specification. This
+  change ensures that the exporter no longer modifies or assumes the value of
+  peer service attributes, aligning it more closely with OpenTelemetry protocol
+  specifications.
+  ([#6005](https://github.com/open-telemetry/opentelemetry-dotnet/pull/6005))
+
 ## 1.10.0
 
 Released 2024-Nov-12

src/OpenTelemetry.Exporter.OpenTelemetryProtocol/Implementation/Serializer/ProtobufOtlpResourceSerializer.cs

@@ -9,9 +9,6 @@ internal static class ProtobufOtlpResourceSerializer
 {
     private const int ReserveSizeForLength = 4;
 
-    private static readonly string DefaultServiceName = ResourceBuilder.CreateDefault().Build().Attributes.FirstOrDefault(
-        kvp => kvp.Key == ResourceSemanticConventions.AttributeServiceName).Value as string ?? "unknown_service";
-
     internal static int WriteResource(byte[] buffer, int writePosition, Resource? resource)
     {
         ProtobufOtlpTagWriter.OtlpTagWriterState otlpTagWriterState = new ProtobufOtlpTagWriter.OtlpTagWriterState
@@ -24,41 +21,24 @@ internal static class ProtobufOtlpResourceSerializer
         int resourceLengthPosition = otlpTagWriterState.WritePosition;
         otlpTagWriterState.WritePosition += ReserveSizeForLength;
 
-        bool isServiceNamePresent = false;
         if (resource != null && resource != Resource.Empty)
         {
             if (resource.Attributes is IReadOnlyList<KeyValuePair<string, object>> resourceAttributesList)
             {
                 for (int i = 0; i < resourceAttributesList.Count; i++)
                 {
-                    var attribute = resourceAttributesList[i];
-                    if (attribute.Key == ResourceSemanticConventions.AttributeServiceName)
-                    {
-                        isServiceNamePresent = true;
-                    }
-
-                    ProcessResourceAttribute(ref otlpTagWriterState, attribute);
+                    ProcessResourceAttribute(ref otlpTagWriterState, resourceAttributesList[i]);
                 }
             }
             else
             {
                 foreach (var attribute in resource.Attributes)
                 {
-                    if (attribute.Key == ResourceSemanticConventions.AttributeServiceName)
-                    {
-                        isServiceNamePresent = true;
-                    }
-
                     ProcessResourceAttribute(ref otlpTagWriterState, attribute);
                 }
             }
         }
 
-        if (!isServiceNamePresent)
-        {
-            ProcessResourceAttribute(ref otlpTagWriterState, new KeyValuePair<string, object>(ResourceSemanticConventions.AttributeServiceName, DefaultServiceName));
-        }
-
         var resourceLength = otlpTagWriterState.WritePosition - (resourceLengthPosition + ReserveSizeForLength);
         ProtobufSerializer.WriteReservedLength(otlpTagWriterState.Buffer, resourceLengthPosition, resourceLength);
 

test/OpenTelemetry.Exporter.OpenTelemetryProtocol.Tests/Implementation/ExportClient/OtlpHttpTraceExportClientTests.cs

@@ -173,7 +173,7 @@ public class OtlpHttpTraceExportClientTests
             }
             else
             {
-                Assert.Contains(resourceSpan.Resource.Attributes, (kvp) => kvp.Key == ResourceSemanticConventions.AttributeServiceName && kvp.Value.ToString().Contains("unknown_service:"));
+                Assert.DoesNotContain(resourceSpan.Resource.Attributes, kvp => kvp.Key == ResourceSemanticConventions.AttributeServiceName);
             }
         }
     }

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

@@ -207,7 +207,7 @@ public class OtlpMetricsExporterTests : IDisposable
         }
         else
         {
-            Assert.Contains(otlpResource.Attributes, (kvp) => kvp.Key == ResourceSemanticConventions.AttributeServiceName && kvp.Value.ToString().Contains("unknown_service:"));
+            Assert.DoesNotContain(otlpResource.Attributes, kvp => kvp.Key == ResourceSemanticConventions.AttributeServiceName);
         }
 
         Assert.Single(resourceMetric.ScopeMetrics);
@@ -943,9 +943,6 @@ public class OtlpMetricsExporterTests : IDisposable
 
         Assert.Single(request.ResourceMetrics);
         var resourceMetric = request.ResourceMetrics.First();
-        var otlpResource = resourceMetric.Resource;
-
-        Assert.Contains(otlpResource.Attributes, (kvp) => kvp.Key == ResourceSemanticConventions.AttributeServiceName && kvp.Value.ToString().Contains("unknown_service:"));
 
         Assert.Single(resourceMetric.ScopeMetrics);
         var instrumentationLibraryMetrics = resourceMetric.ScopeMetrics.First();

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

@@ -43,7 +43,7 @@ public class OtlpResourceTests
         }
         else
         {
-            Assert.Contains(otlpResource.Attributes, (kvp) => kvp.Key == ResourceSemanticConventions.AttributeServiceName && kvp.Value.ToString().Contains("unknown_service:"));
+            Assert.DoesNotContain(otlpResource.Attributes, kvp => kvp.Key == ResourceSemanticConventions.AttributeServiceName);
         }
     }
 }

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

@@ -184,7 +184,7 @@ public class OtlpTraceExporterTests
             }
             else
             {
-                Assert.Contains(otlpResource.Attributes, (kvp) => kvp.Key == ResourceSemanticConventions.AttributeServiceName && kvp.Value.ToString().Contains("unknown_service:"));
+                Assert.DoesNotContain(otlpResource.Attributes, kvp => kvp.Key == ResourceSemanticConventions.AttributeServiceName);
             }
 
             var scopeSpans = request.ResourceSpans.First().ScopeSpans;