[release/9.0] Fix error adding log entry with no body

playground/Stress/Stress.ApiService/Program.cs

@@ -4,7 +4,13 @@
 using System.Diagnostics;
 using System.Text;
 using System.Threading.Channels;
+using Grpc.Core;
+using Grpc.Net.Client;
 using Microsoft.AspNetCore.Mvc;
+using OpenTelemetry.Proto.Collector.Logs.V1;
+using OpenTelemetry.Proto.Common.V1;
+using OpenTelemetry.Proto.Logs.V1;
+using OpenTelemetry.Proto.Resource.V1;
 using Stress.ApiService;
 
 var builder = WebApplication.CreateBuilder(args);
@@ -225,4 +231,54 @@ async IAsyncEnumerable<string> WriteOutput()
     return $"Created duplicate span IDs.";
 });
 
+app.MapGet("/log-entry-nobody", async (IConfiguration configuration) =>
+{
+    var channel = GrpcChannel.ForAddress(configuration["OTEL_EXPORTER_OTLP_ENDPOINT"]!);
+
+    var resource = new Resource();
+    resource.Attributes.Add(new KeyValue { Key = "service.name", Value = new AnyValue { StringValue = configuration["OTEL_SERVICE_NAME"]! } });
+
+    foreach (var item in configuration["OTEL_RESOURCE_ATTRIBUTES"]!.Split(';'))
+    {
+        var headerParts = item.Split('=');
+
+        resource.Attributes.Add(new KeyValue { Key = headerParts[0], Value = new AnyValue { StringValue = headerParts[1] } });
+    }
+
+    var metadata = new Metadata();
+    foreach (var item in configuration["OTEL_EXPORTER_OTLP_HEADERS"]!.Split(';'))
+    {
+        var headerParts = item.Split('=');
+
+        metadata.Add(headerParts[0], headerParts[1]);
+    }
+
+    var client = new LogsService.LogsServiceClient(channel);
+    var response = await client.ExportAsync(new ExportLogsServiceRequest
+    {
+        ResourceLogs =
+        {
+            new ResourceLogs
+            {
+                Resource = resource,
+                ScopeLogs =
+                {
+                    new ScopeLogs
+                    {
+                        Scope = new InstrumentationScope { Name = "NoBodySource" },
+                        LogRecords =
+                        {
+                            new LogRecord
+                            {
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    }, metadata);
+
+    return response.PartialSuccess?.RejectedLogRecords > 0 ? "Failure" : "Success";
+});
+
 app.Run();

playground/Stress/Stress.ApiService/Stress.ApiService.csproj

@@ -16,4 +16,11 @@
     <ProjectReference Include="..\..\Playground.ServiceDefaults\Playground.ServiceDefaults.csproj" />
   </ItemGroup>
 
+  <ItemGroup>
+    <PackageReference Include="Grpc.Tools" />
+    <Protobuf Include="..\..\..\src\Aspire.Dashboard\Otlp\**\*.proto">
+      <ProtoRoot>..\..\..\src\Aspire.Dashboard\Otlp</ProtoRoot>
+    </Protobuf>
+  </ItemGroup>
+
 </Project>

src/Aspire.Dashboard/Otlp/Model/OtlpLogEntry.cs

@@ -52,7 +52,9 @@ public OtlpLogEntry(LogRecord record, OtlpApplicationView logApp, OtlpScope scop
         Flags = record.Flags;
         Severity = MapSeverity(record.SeverityNumber);
 
-        Message = OtlpHelpers.TruncateString(record.Body.GetString(), context.Options.MaxAttributeLength);
+        Message = record.Body is { } body
+            ? OtlpHelpers.TruncateString(body.GetString(), context.Options.MaxAttributeLength)
+            : string.Empty;
         OriginalFormat = originalFormat;
         SpanId = record.SpanId.ToHexString();
         TraceId = record.TraceId.ToHexString();

tests/Aspire.Dashboard.Tests/TelemetryRepositoryTests/LogTests.cs

@@ -90,6 +90,47 @@ public void AddLogs()
             s => Assert.Equal("Log", s));
     }
 
+    [Fact]
+    public void AddLogs_NoBody_EmptyMessage()
+    {
+        // Arrange
+        var repository = CreateRepository();
+
+        // Act
+        var addContext = new AddContext();
+        repository.AddLogs(addContext, new RepeatedField<ResourceLogs>()
+        {
+            new ResourceLogs
+            {
+                Resource = CreateResource(),
+                ScopeLogs =
+                {
+                    new ScopeLogs
+                    {
+                        Scope = CreateScope("TestLogger"),
+                        LogRecords = { CreateLogRecord(skipBody: true) }
+                    }
+                }
+            }
+        });
+
+        // Assert
+        Assert.Equal(0, addContext.FailureCount);
+
+        var logs = repository.GetLogs(new GetLogsContext
+        {
+            ApplicationKey = null,
+            StartIndex = 0,
+            Count = 10,
+            Filters = []
+        });
+        Assert.Collection(logs.Items,
+            app =>
+            {
+                Assert.Equal("", app.Message);
+            });
+    }
+
     [Fact]
     public void AddLogs_MultipleOutOfOrder()
     {

tests/Shared/Telemetry/TelemetryTestHelpers.cs

@@ -174,13 +174,13 @@ public static Span CreateSpan(string traceId, string spanId, DateTime startTime,
         return span;
     }
 
-    public static LogRecord CreateLogRecord(DateTime? time = null, string? message = null, SeverityNumber? severity = null, IEnumerable<KeyValuePair<string, string>>? attributes = null)
+    public static LogRecord CreateLogRecord(DateTime? time = null, string? message = null, SeverityNumber? severity = null, IEnumerable<KeyValuePair<string, string>>? attributes = null, bool? skipBody = null)
     {
         attributes ??= [new KeyValuePair<string, string>("{OriginalFormat}", "Test {Log}"), new KeyValuePair<string, string>("Log", "Value!")];
 
         var logRecord = new LogRecord
         {
-            Body = new AnyValue { StringValue = message ?? "Test Value!" },
+            Body = (skipBody ?? false) ? null : new AnyValue { StringValue = message ?? "Test Value!" },
             TraceId = ByteString.CopyFrom(Convert.FromHexString("5465737454726163654964")),
             SpanId = ByteString.CopyFrom(Convert.FromHexString("546573745370616e4964")),
             TimeUnixNano = time != null ? DateTimeToUnixNanoseconds(time.Value) : 1000,