[otlp] Fix TODOs, Refactor Buffer Size Handling, and Cleanup Environm…

…ent Variables (#6009)

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

src/OpenTelemetry.Exporter.OpenTelemetryProtocol/Builder/OpenTelemetryBuilderOtlpExporterExtensions.cs

@@ -88,8 +88,8 @@ internal static IOpenTelemetryBuilder UseOtlpExporter(
     /// <para><see cref="IConfiguration"/> to bind onto <see cref="OtlpExporterBuilderOptions"/>.</para>
     /// <para>Notes:
     /// <list type="bullet">
-    /// <item docLink="true">See [TODO:Add doc link] for details on the configuration
-    /// schema.</item>
+    /// <item docLink="true"><see href="https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/protocol/exporter.md"/>
+    /// for details on the configuration schema.</item>
     /// <item>The <see cref="OtlpExporterBuilderOptions"/> instance will be
     /// named "otlp" by default when calling this method.</item>
     /// </list>

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

@@ -17,8 +17,6 @@ internal sealed class ExperimentalOptions
 
     public const string OtlpDiskRetryDirectoryPathEnvVar = "OTEL_DOTNET_EXPERIMENTAL_OTLP_DISK_RETRY_DIRECTORY_PATH";
 
-    public const string OtlpUseCustomSerializer = "OTEL_DOTNET_EXPERIMENTAL_USE_CUSTOM_PROTOBUF_SERIALIZER";
-
     public ExperimentalOptions()
         : this(new ConfigurationBuilder().AddEnvironmentVariables().Build())
     {
@@ -31,11 +29,6 @@ public ExperimentalOptions(IConfiguration configuration)
             this.EmitLogEventAttributes = emitLogEventAttributes;
         }
 
-        if (configuration.TryGetBoolValue(OpenTelemetryProtocolExporterEventSource.Log, OtlpUseCustomSerializer, out var useCustomSerializer))
-        {
-            this.UseCustomProtobufSerializer = useCustomSerializer;
-        }
-
         if (configuration.TryGetStringValue(OtlpRetryEnvVar, out var retryPolicy) && retryPolicy != null)
         {
             if (retryPolicy.Equals("in_memory", StringComparison.OrdinalIgnoreCase))
@@ -85,9 +78,4 @@ public ExperimentalOptions(IConfiguration configuration)
     /// Gets the path on disk where the telemetry will be stored for retries at a later point.
     /// </summary>
     public string? DiskRetryDirectoryPath { get; }
-
-    /// <summary>
-    /// Gets a value indicating whether custom serializer should be used for OTLP export.
-    /// </summary>
-    public bool UseCustomProtobufSerializer { get; }
 }

src/OpenTelemetry.Exporter.OpenTelemetryProtocol/Implementation/ExportClient/Grpc/GrpcStatusDeserializer.cs

@@ -26,9 +26,9 @@ internal static class GrpcStatusDeserializer
                        TimeSpan.FromTicks(retryInfo.Value.RetryDelay.Value.Nanos / 100); // Convert nanos to ticks
             }
         }
-        catch
+        catch (Exception ex)
         {
-            // TODO: Log exception to event source.
+            OpenTelemetryProtocolExporterEventSource.Log.GrpcRetryDelayParsingFailed(grpcStatusDetailsHeader, ex);
             return null;
         }
 

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

@@ -85,6 +85,15 @@ public void RequestTimedOut(Uri endpoint, Exception ex)
         }
     }
 
+    [NonEvent]
+    public void GrpcRetryDelayParsingFailed(string? grpcStatusDetailsHeader, Exception ex)
+    {
+        if (Log.IsEnabled(EventLevel.Warning, EventKeywords.All))
+        {
+            this.GrpcRetryDelayParsingFailed(grpcStatusDetailsHeader ?? "null", ex.ToInvariantString());
+        }
+    }
+
     [Event(2, Message = "Exporter failed send data to collector to {0} endpoint. Data will not be sent. Exception: {1}", Level = EventLevel.Error)]
     public void FailedToReachCollector(string rawCollectorUri, string ex)
     {
@@ -205,6 +214,12 @@ public void ExportFailure(string endpoint, string message)
         this.WriteEvent(23, endpoint, message);
     }
 
+    [Event(24, Message = "Failed to parse gRPC retry delay from header grpcStatusDetailsHeader: '{0}'. Exception: {1}", Level = EventLevel.Warning)]
+    public void GrpcRetryDelayParsingFailed(string grpcStatusDetailsHeader, string exception)
+    {
+        this.WriteEvent(24, grpcStatusDetailsHeader, exception);
+    }
+
     void IConfigurationExtensionsLogger.LogInvalidConfigurationValue(string key, string value)
     {
         this.InvalidConfigurationValue(key, value);

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

@@ -47,13 +47,32 @@ internal static int WriteLogsData(byte[] buffer, int writePosition, SdkLimitOpti
             logRecords.Add(logRecord);
         }
 
-        writePosition = WriteResourceLogs(buffer, writePosition, sdkLimitOptions, experimentalOptions, resource, ScopeLogsList);
+        writePosition = TryWriteResourceLogs(buffer, writePosition, sdkLimitOptions, experimentalOptions, resource, ScopeLogsList);
         ProtobufSerializer.WriteReservedLength(buffer, logsDataLengthPosition, writePosition - (logsDataLengthPosition + ReserveSizeForLength));
         ReturnLogRecordListToPool();
 
         return writePosition;
     }
 
+    internal static int TryWriteResourceLogs(byte[] buffer, int writePosition, SdkLimitOptions sdkLimitOptions, ExperimentalOptions experimentalOptions, Resources.Resource? resource, Dictionary<string, List<LogRecord>> scopeLogs)
+    {
+        try
+        {
+            writePosition = WriteResourceLogs(buffer, writePosition, sdkLimitOptions, experimentalOptions, resource, scopeLogs);
+        }
+        catch (IndexOutOfRangeException)
+        {
+            if (!ProtobufSerializer.IncreaseBufferSize(ref buffer, OtlpSignalType.Logs))
+            {
+                throw;
+            }
+
+            return TryWriteResourceLogs(buffer, writePosition, sdkLimitOptions, experimentalOptions, resource, scopeLogs);
+        }
+
+        return writePosition;
+    }
+
     internal static void ReturnLogRecordListToPool()
     {
         if (ScopeLogsList.Count != 0)

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

@@ -35,13 +35,32 @@ internal static int WriteMetricsData(byte[] buffer, int writePosition, Resources
             metrics.Add(metric);
         }
 
-        writePosition = WriteResourceMetrics(buffer, writePosition, resource, ScopeMetricsList);
+        writePosition = TryWriteResourceMetrics(buffer, writePosition, resource, ScopeMetricsList);
         ProtobufSerializer.WriteReservedLength(buffer, mericsDataLengthPosition, writePosition - (mericsDataLengthPosition + ReserveSizeForLength));
         ReturnMetricListToPool();
 
         return writePosition;
     }
 
+    internal static int TryWriteResourceMetrics(byte[] buffer, int writePosition, Resources.Resource? resource, Dictionary<string, List<Metric>> scopeMetrics)
+    {
+        try
+        {
+            writePosition = WriteResourceMetrics(buffer, writePosition, resource, scopeMetrics);
+        }
+        catch (IndexOutOfRangeException)
+        {
+            if (!ProtobufSerializer.IncreaseBufferSize(ref buffer, OtlpSignalType.Metrics))
+            {
+                throw;
+            }
+
+            return TryWriteResourceMetrics(buffer, writePosition, resource, scopeMetrics);
+        }
+
+        return writePosition;
+    }
+
     private static void ReturnMetricListToPool()
     {
         if (ScopeMetricsList.Count != 0)

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

@@ -63,10 +63,6 @@ internal static int TryWriteResourceSpans(byte[] buffer, int writePosition, SdkL
             // and avoids stack overflow.
             return TryWriteResourceSpans(buffer, writePosition, sdkLimitOptions, resource);
         }
-        catch
-        {
-            throw;
-        }
 
         return writePosition;
     }

src/OpenTelemetry.Exporter.OpenTelemetryProtocol/OtlpExporterOptionsExtensions.cs

@@ -58,9 +58,9 @@ public static THeaders GetHeaders<THeaders>(this OtlpExporterOptions options, Ac
         return headers;
     }
 
-    public static OtlpExporterTransmissionHandler GetProtobufExportTransmissionHandler(this OtlpExporterOptions options, ExperimentalOptions experimentalOptions, OtlpSignalType otlpSignalType)
+    public static OtlpExporterTransmissionHandler GetExportTransmissionHandler(this OtlpExporterOptions options, ExperimentalOptions experimentalOptions, OtlpSignalType otlpSignalType)
     {
-        var exportClient = GetProtobufExportClient(options, otlpSignalType);
+        var exportClient = GetExportClient(options, otlpSignalType);
 
         // `HttpClient.Timeout.TotalMilliseconds` would be populated with the correct timeout value for both the exporter configuration cases:
         // 1. User provides their own HttpClient. This case is straightforward as the user wants to use their `HttpClient` and thereby the same client's timeout value.
@@ -88,7 +88,7 @@ public static OtlpExporterTransmissionHandler GetProtobufExportTransmissionHandl
         }
     }
 
-    public static IExportClient GetProtobufExportClient(this OtlpExporterOptions options, OtlpSignalType otlpSignalType)
+    public static IExportClient GetExportClient(this OtlpExporterOptions options, OtlpSignalType otlpSignalType)
     {
         var httpClient = options.HttpClientFactory?.Invoke() ?? throw new InvalidOperationException("OtlpExporterOptions was missing HttpClientFactory or it returned null.");
 

src/OpenTelemetry.Exporter.OpenTelemetryProtocol/OtlpLogExporter.cs

@@ -17,6 +17,7 @@ namespace OpenTelemetry.Exporter;
 /// </summary>
 public sealed class OtlpLogExporter : BaseExporter<LogRecord>
 {
+    private const int GrpcStartWritePosition = 5;
     private readonly SdkLimitOptions sdkLimitOptions;
     private readonly ExperimentalOptions experimentalOptions;
     private readonly OtlpExporterTransmissionHandler transmissionHandler;
@@ -57,8 +58,8 @@ internal OtlpLogExporter(
 
         this.experimentalOptions = experimentalOptions!;
         this.sdkLimitOptions = sdkLimitOptions!;
-        this.startWritePosition = exporterOptions!.Protocol == OtlpExportProtocol.Grpc ? 5 : 0;
-        this.transmissionHandler = transmissionHandler ?? exporterOptions!.GetProtobufExportTransmissionHandler(experimentalOptions!, OtlpSignalType.Logs);
+        this.startWritePosition = exporterOptions!.Protocol == OtlpExportProtocol.Grpc ? GrpcStartWritePosition : 0;
+        this.transmissionHandler = transmissionHandler ?? exporterOptions!.GetExportTransmissionHandler(experimentalOptions!, OtlpSignalType.Logs);
     }
 
     internal Resource Resource => this.resource ??= this.ParentProvider.GetResource();
@@ -73,14 +74,14 @@ public override ExportResult Export(in Batch<LogRecord> logRecordBatch)
         {
             int writePosition = ProtobufOtlpLogSerializer.WriteLogsData(this.buffer, this.startWritePosition, this.sdkLimitOptions, this.experimentalOptions, this.Resource, logRecordBatch);
 
-            if (this.startWritePosition == 5)
+            if (this.startWritePosition == GrpcStartWritePosition)
             {
                 // Grpc payload consists of 3 parts
                 // byte 0 - Specifying if the payload is compressed.
                 // 1-4 byte - Specifies the length of payload in big endian format.
                 // 5 and above -  Protobuf serialized data.
                 Span<byte> data = new Span<byte>(this.buffer, 1, 4);
-                var dataLength = writePosition - 5;
+                var dataLength = writePosition - GrpcStartWritePosition;
                 BinaryPrimitives.WriteUInt32BigEndian(data, (uint)dataLength);
             }
 
@@ -89,13 +90,6 @@ public override ExportResult Export(in Batch<LogRecord> logRecordBatch)
                 return ExportResult.Failure;
             }
         }
-        catch (IndexOutOfRangeException)
-        {
-            if (!this.IncreaseBufferSize())
-            {
-                throw;
-            }
-        }
         catch (Exception ex)
         {
             OpenTelemetryProtocolExporterEventSource.Log.ExportMethodException(ex);
@@ -107,21 +101,4 @@ public override ExportResult Export(in Batch<LogRecord> logRecordBatch)
 
     /// <inheritdoc />
     protected override bool OnShutdown(int timeoutMilliseconds) => this.transmissionHandler?.Shutdown(timeoutMilliseconds) ?? true;
-
-    // TODO: Consider moving this to a shared utility class.
-    private bool IncreaseBufferSize()
-    {
-        var newBufferSize = this.buffer.Length * 2;
-
-        if (newBufferSize > 100 * 1024 * 1024)
-        {
-            return false;
-        }
-
-        var newBuffer = new byte[newBufferSize];
-        this.buffer.CopyTo(newBuffer, 0);
-        this.buffer = newBuffer;
-
-        return true;
-    }
 }

src/OpenTelemetry.Exporter.OpenTelemetryProtocol/OtlpMetricExporter.cs

@@ -17,6 +17,7 @@ namespace OpenTelemetry.Exporter;
 /// </summary>
 public class OtlpMetricExporter : BaseExporter<Metric>
 {
+    private const int GrpcStartWritePosition = 5;
     private readonly OtlpExporterTransmissionHandler transmissionHandler;
     private readonly int startWritePosition;
 
@@ -50,8 +51,8 @@ internal OtlpMetricExporter(
         Debug.Assert(exporterOptions != null, "exporterOptions was null");
         Debug.Assert(experimentalOptions != null, "experimentalOptions was null");
 
-        this.startWritePosition = exporterOptions!.Protocol == OtlpExportProtocol.Grpc ? 5 : 0;
-        this.transmissionHandler = transmissionHandler ?? exporterOptions!.GetProtobufExportTransmissionHandler(experimentalOptions!, OtlpSignalType.Metrics);
+        this.startWritePosition = exporterOptions!.Protocol == OtlpExportProtocol.Grpc ? GrpcStartWritePosition : 0;
+        this.transmissionHandler = transmissionHandler ?? exporterOptions!.GetExportTransmissionHandler(experimentalOptions!, OtlpSignalType.Metrics);
     }
 
     internal Resource Resource => this.resource ??= this.ParentProvider.GetResource();
@@ -66,14 +67,14 @@ public override ExportResult Export(in Batch<Metric> metrics)
         {
             int writePosition = ProtobufOtlpMetricSerializer.WriteMetricsData(this.buffer, this.startWritePosition, this.Resource, metrics);
 
-            if (this.startWritePosition == 5)
+            if (this.startWritePosition == GrpcStartWritePosition)
             {
                 // Grpc payload consists of 3 parts
                 // byte 0 - Specifying if the payload is compressed.
                 // 1-4 byte - Specifies the length of payload in big endian format.
                 // 5 and above -  Protobuf serialized data.
                 Span<byte> data = new Span<byte>(this.buffer, 1, 4);
-                var dataLength = writePosition - 5;
+                var dataLength = writePosition - GrpcStartWritePosition;
                 BinaryPrimitives.WriteUInt32BigEndian(data, (uint)dataLength);
             }
 
@@ -82,13 +83,6 @@ public override ExportResult Export(in Batch<Metric> metrics)
                 return ExportResult.Failure;
             }
         }
-        catch (IndexOutOfRangeException)
-        {
-            if (!this.IncreaseBufferSize())
-            {
-                throw;
-            }
-        }
         catch (Exception ex)
         {
             OpenTelemetryProtocolExporterEventSource.Log.ExportMethodException(ex);
@@ -100,21 +94,4 @@ public override ExportResult Export(in Batch<Metric> metrics)
 
     /// <inheritdoc />
     protected override bool OnShutdown(int timeoutMilliseconds) => this.transmissionHandler.Shutdown(timeoutMilliseconds);
-
-    // TODO: Consider moving this to a shared utility class.
-    private bool IncreaseBufferSize()
-    {
-        var newBufferSize = this.buffer.Length * 2;
-
-        if (newBufferSize > 100 * 1024 * 1024)
-        {
-            return false;
-        }
-
-        var newBuffer = new byte[newBufferSize];
-        this.buffer.CopyTo(newBuffer, 0);
-        this.buffer = newBuffer;
-
-        return true;
-    }
 }

src/OpenTelemetry.Exporter.OpenTelemetryProtocol/OtlpTraceExporter.cs

@@ -16,6 +16,7 @@ namespace OpenTelemetry.Exporter;
 /// </summary>
 public class OtlpTraceExporter : BaseExporter<Activity>
 {
+    private const int GrpcStartWritePosition = 5;
     private readonly SdkLimitOptions sdkLimitOptions;
     private readonly OtlpExporterTransmissionHandler transmissionHandler;
     private readonly int startWritePosition;
@@ -53,8 +54,8 @@ internal OtlpTraceExporter(
         Debug.Assert(sdkLimitOptions != null, "sdkLimitOptions was null");
 
         this.sdkLimitOptions = sdkLimitOptions!;
-        this.startWritePosition = exporterOptions!.Protocol == OtlpExportProtocol.Grpc ? 5 : 0;
-        this.transmissionHandler = transmissionHandler ?? exporterOptions!.GetProtobufExportTransmissionHandler(experimentalOptions, OtlpSignalType.Traces);
+        this.startWritePosition = exporterOptions!.Protocol == OtlpExportProtocol.Grpc ? GrpcStartWritePosition : 0;
+        this.transmissionHandler = transmissionHandler ?? exporterOptions!.GetExportTransmissionHandler(experimentalOptions, OtlpSignalType.Traces);
     }
 
     internal Resource Resource => this.resource ??= this.ParentProvider.GetResource();
@@ -69,14 +70,14 @@ public override ExportResult Export(in Batch<Activity> activityBatch)
         {
             int writePosition = ProtobufOtlpTraceSerializer.WriteTraceData(this.buffer, this.startWritePosition, this.sdkLimitOptions, this.Resource, activityBatch);
 
-            if (this.startWritePosition == 5)
+            if (this.startWritePosition == GrpcStartWritePosition)
             {
                 // Grpc payload consists of 3 parts
                 // byte 0 - Specifying if the payload is compressed.
                 // 1-4 byte - Specifies the length of payload in big endian format.
                 // 5 and above -  Protobuf serialized data.
                 Span<byte> data = new Span<byte>(this.buffer, 1, 4);
-                var dataLength = writePosition - 5;
+                var dataLength = writePosition - GrpcStartWritePosition;
                 BinaryPrimitives.WriteUInt32BigEndian(data, (uint)dataLength);
             }