[otlp] Enable OTLP exporter for multiple registrations

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

@@ -14,21 +14,26 @@ internal static class ProtobufOtlpLogSerializer
     private const int TraceIdSize = 16;
     private const int SpanIdSize = 8;
 
-    private static readonly Stack<List<LogRecord>> LogsListPool = [];
-    private static readonly Dictionary<string, List<LogRecord>> ScopeLogsList = [];
+    [ThreadStatic]
+    private static Stack<List<LogRecord>>? logsListPool;
+    [ThreadStatic]
+    private static Dictionary<string, List<LogRecord>>? scopeLogsList;
 
     [ThreadStatic]
     private static SerializationState? threadSerializationState;
 
     internal static int WriteLogsData(ref byte[] buffer, int writePosition, SdkLimitOptions sdkLimitOptions, ExperimentalOptions experimentalOptions, Resources.Resource? resource, in Batch<LogRecord> logRecordBatch)
     {
+        logsListPool ??= [];
+        scopeLogsList ??= [];
+
         foreach (var logRecord in logRecordBatch)
         {
             var scopeName = logRecord.Logger.Name;
-            if (!ScopeLogsList.TryGetValue(scopeName, out var logRecords))
+            if (!scopeLogsList.TryGetValue(scopeName, out var logRecords))
             {
-                logRecords = LogsListPool.Count > 0 ? LogsListPool.Pop() : [];
-                ScopeLogsList[scopeName] = logRecords;
+                logRecords = logsListPool.Count > 0 ? logsListPool.Pop() : [];
+                scopeLogsList[scopeName] = logRecords;
             }
 
             if (logRecord.Source == LogRecord.LogRecordSource.FromSharedPool)
@@ -43,7 +48,7 @@ internal static int WriteLogsData(ref byte[] buffer, int writePosition, SdkLimit
             logRecords.Add(logRecord);
         }
 
-        writePosition = TryWriteResourceLogs(ref buffer, writePosition, sdkLimitOptions, experimentalOptions, resource, ScopeLogsList);
+        writePosition = TryWriteResourceLogs(ref buffer, writePosition, sdkLimitOptions, experimentalOptions, resource, scopeLogsList);
         ReturnLogRecordListToPool();
 
         return writePosition;
@@ -79,9 +84,9 @@ internal static int TryWriteResourceLogs(ref byte[] buffer, int writePosition, S
 
     internal static void ReturnLogRecordListToPool()
     {
-        if (ScopeLogsList.Count != 0)
+        if (scopeLogsList?.Count != 0)
         {
-            foreach (var entry in ScopeLogsList)
+            foreach (var entry in scopeLogsList!)
             {
                 foreach (var logRecord in entry.Value)
                 {
@@ -96,10 +101,10 @@ internal static void ReturnLogRecordListToPool()
                 }
 
                 entry.Value.Clear();
-                LogsListPool.Push(entry.Value);
+                logsListPool?.Push(entry.Value);
             }
 
-            ScopeLogsList.Clear();
+            scopeLogsList.Clear();
         }
     }
 

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

@@ -12,26 +12,31 @@ internal static class ProtobufOtlpMetricSerializer
     private const int TraceIdSize = 16;
     private const int SpanIdSize = 8;
 
-    private static readonly Stack<List<Metric>> MetricListPool = [];
-    private static readonly Dictionary<string, List<Metric>> ScopeMetricsList = [];
+    [ThreadStatic]
+    private static Stack<List<Metric>>? metricListPool;
+    [ThreadStatic]
+    private static Dictionary<string, List<Metric>>? scopeMetricsList;
 
     private delegate int WriteExemplarFunc(byte[] buffer, int writePosition, in Exemplar exemplar);
 
     internal static int WriteMetricsData(ref byte[] buffer, int writePosition, Resources.Resource? resource, in Batch<Metric> batch)
     {
+        metricListPool ??= [];
+        scopeMetricsList ??= [];
+
         foreach (var metric in batch)
         {
             var metricName = metric.MeterName;
-            if (!ScopeMetricsList.TryGetValue(metricName, out var metrics))
+            if (!scopeMetricsList.TryGetValue(metricName, out var metrics))
             {
-                metrics = MetricListPool.Count > 0 ? MetricListPool.Pop() : new List<Metric>();
-                ScopeMetricsList[metricName] = metrics;
+                metrics = metricListPool.Count > 0 ? metricListPool.Pop() : new List<Metric>();
+                scopeMetricsList[metricName] = metrics;
             }
 
             metrics.Add(metric);
         }
 
-        writePosition = TryWriteResourceMetrics(ref buffer, writePosition, resource, ScopeMetricsList);
+        writePosition = TryWriteResourceMetrics(ref buffer, writePosition, resource, scopeMetricsList);
         ReturnMetricListToPool();
 
         return writePosition;
@@ -67,15 +72,15 @@ internal static int TryWriteResourceMetrics(ref byte[] buffer, int writePosition
 
     private static void ReturnMetricListToPool()
     {
-        if (ScopeMetricsList.Count != 0)
+        if (scopeMetricsList?.Count != 0)
         {
-            foreach (var entry in ScopeMetricsList)
+            foreach (var entry in scopeMetricsList!)
             {
                 entry.Value.Clear();
-                MetricListPool.Push(entry.Value);
+                metricListPool?.Push(entry.Value);
             }
 
-            ScopeMetricsList.Clear();
+            scopeMetricsList.Clear();
         }
     }
 

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

@@ -15,18 +15,23 @@ internal static class ProtobufOtlpTraceSerializer
     private const int TraceIdSize = 16;
     private const int SpanIdSize = 8;
 
-    private static readonly Stack<List<Activity>> ActivityListPool = [];
-    private static readonly Dictionary<string, List<Activity>> ScopeTracesList = [];
+    [ThreadStatic]
+    private static Stack<List<Activity>>? activityListPool;
+    [ThreadStatic]
+    private static Dictionary<string, List<Activity>>? scopeTracesList;
 
     internal static int WriteTraceData(ref byte[] buffer, int writePosition, SdkLimitOptions sdkLimitOptions, Resources.Resource? resource, in Batch<Activity> batch)
     {
+        activityListPool ??= [];
+        scopeTracesList ??= [];
+
         foreach (var activity in batch)
         {
             var sourceName = activity.Source.Name;
-            if (!ScopeTracesList.TryGetValue(sourceName, out var activities))
+            if (!scopeTracesList.TryGetValue(sourceName, out var activities))
             {
-                activities = ActivityListPool.Count > 0 ? ActivityListPool.Pop() : [];
-                ScopeTracesList[sourceName] = activities;
+                activities = activityListPool.Count > 0 ? activityListPool.Pop() : [];
+                scopeTracesList[sourceName] = activities;
             }
 
             activities.Add(activity);
@@ -74,15 +79,15 @@ internal static int TryWriteResourceSpans(ref byte[] buffer, int writePosition,
 
     internal static void ReturnActivityListToPool()
     {
-        if (ScopeTracesList.Count != 0)
+        if (scopeTracesList?.Count != 0)
         {
-            foreach (var entry in ScopeTracesList)
+            foreach (var entry in scopeTracesList!)
             {
                 entry.Value.Clear();
-                ActivityListPool.Push(entry.Value);
+                activityListPool?.Push(entry.Value);
             }
 
-            ScopeTracesList.Clear();
+            scopeTracesList.Clear();
         }
     }
 
@@ -96,9 +101,9 @@ internal static int WriteResourceSpans(byte[] buffer, int writePosition, SdkLimi
 
     internal static int WriteScopeSpans(byte[] buffer, int writePosition, SdkLimitOptions sdkLimitOptions)
     {
-        if (ScopeTracesList != null)
+        if (scopeTracesList != null)
         {
-            foreach (KeyValuePair<string, List<Activity>> entry in ScopeTracesList)
+            foreach (KeyValuePair<string, List<Activity>> entry in scopeTracesList)
             {
                 writePosition = ProtobufSerializer.WriteTag(buffer, writePosition, ProtobufOtlpTraceFieldNumberConstants.ResourceSpans_Scope_Spans, ProtobufWireType.LEN);
                 int resourceSpansScopeSpansLengthPosition = writePosition;