[1.3.0 patch] Future-proof OTLP exporter against future breaking changes (#3622)

Author: alanwest

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

@@ -36,7 +36,7 @@ namespace OpenTelemetry.Exporter.OpenTelemetryProtocol.Implementation
     internal static class ActivityExtensions
     {
         private static readonly ConcurrentBag<OtlpTrace.ScopeSpans> SpanListPool = new();
-        private static readonly Action<RepeatedField<OtlpTrace.Span>, int> RepeatedFieldOfSpanSetCountAction = CreateRepeatedFieldOfSpanSetCountAction();
+        private static Action<RepeatedField<OtlpTrace.Span>, int> repeatedFieldOfSpanSetCountAction = CreateRepeatedFieldOfSpanSetCountAction();
 
         internal static void AddBatch(
             this OtlpCollector.ExportTraceServiceRequest request,
@@ -77,6 +77,11 @@ internal static void AddBatch(
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         internal static void Return(this OtlpCollector.ExportTraceServiceRequest request)
         {
+            if (repeatedFieldOfSpanSetCountAction == null)
+            {
+                return;
+            }
+
             var resourceSpans = request.ResourceSpans.FirstOrDefault();
             if (resourceSpans == null)
             {
@@ -85,15 +90,24 @@ internal static void Return(this OtlpCollector.ExportTraceServiceRequest request
 
             foreach (var scope in resourceSpans.ScopeSpans)
             {
-                RepeatedFieldOfSpanSetCountAction(scope.Spans, 0);
+                try
+                {
+                    repeatedFieldOfSpanSetCountAction(scope.Spans, 0);
+                }
+                catch
+                {
+                    repeatedFieldOfSpanSetCountAction = null;
+                    return;
+                }
+
                 SpanListPool.Add(scope);
             }
         }
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         internal static OtlpTrace.ScopeSpans GetSpanListFromPool(string name, string version)
         {
-            if (!SpanListPool.TryTake(out var spans))
+            if (repeatedFieldOfSpanSetCountAction == null || !SpanListPool.TryTake(out var spans))
             {
                 spans = new OtlpTrace.ScopeSpans
                 {
@@ -293,6 +307,11 @@ private static OtlpTrace.Span.Types.Event ToOtlpEvent(ActivityEvent activityEven
         {
             FieldInfo repeatedFieldOfSpanCountField = typeof(RepeatedField<OtlpTrace.Span>).GetField("count", BindingFlags.NonPublic | BindingFlags.Instance);
 
+            if (repeatedFieldOfSpanCountField == null)
+            {
+                return null;
+            }
+
             DynamicMethod dynamicMethod = new DynamicMethod(
                 "CreateSetCountAction",
                 null,

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

@@ -33,7 +33,7 @@ namespace OpenTelemetry.Exporter.OpenTelemetryProtocol.Implementation
     internal static class MetricItemExtensions
     {
         private static readonly ConcurrentBag<OtlpMetrics.ScopeMetrics> MetricListPool = new();
-        private static readonly Action<RepeatedField<OtlpMetrics.Metric>, int> RepeatedFieldOfMetricSetCountAction = CreateRepeatedFieldOfMetricSetCountAction();
+        private static Action<RepeatedField<OtlpMetrics.Metric>, int> repeatedFieldOfMetricSetCountAction = CreateRepeatedFieldOfMetricSetCountAction();
 
         internal static void AddMetrics(
             this OtlpCollector.ExportMetricsServiceRequest request,
@@ -76,6 +76,11 @@ internal static void AddMetrics(
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         internal static void Return(this OtlpCollector.ExportMetricsServiceRequest request)
         {
+            if (repeatedFieldOfMetricSetCountAction == null)
+            {
+                return;
+            }
+
             var resourceMetrics = request.ResourceMetrics.FirstOrDefault();
             if (resourceMetrics == null)
             {
@@ -84,15 +89,24 @@ internal static void Return(this OtlpCollector.ExportMetricsServiceRequest reque
 
             foreach (var scope in resourceMetrics.ScopeMetrics)
             {
-                RepeatedFieldOfMetricSetCountAction(scope.Metrics, 0);
+                try
+                {
+                    repeatedFieldOfMetricSetCountAction(scope.Metrics, 0);
+                }
+                catch
+                {
+                    repeatedFieldOfMetricSetCountAction = null;
+                    return;
+                }
+
                 MetricListPool.Add(scope);
             }
         }
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         internal static OtlpMetrics.ScopeMetrics GetMetricListFromPool(string name, string version)
         {
-            if (!MetricListPool.TryTake(out var metrics))
+            if (repeatedFieldOfMetricSetCountAction == null || !MetricListPool.TryTake(out var metrics))
             {
                 metrics = new OtlpMetrics.ScopeMetrics
                 {
@@ -338,6 +352,11 @@ private static OtlpMetrics.Exemplar ToOtlpExemplar(this IExemplar exemplar)
         {
             FieldInfo repeatedFieldOfMetricCountField = typeof(RepeatedField<OtlpMetrics.Metric>).GetField("count", BindingFlags.NonPublic | BindingFlags.Instance);
 
+            if (repeatedFieldOfMetricCountField == null)
+            {
+                return null;
+            }
+
             DynamicMethod dynamicMethod = new DynamicMethod(
                 "CreateSetCountAction",
                 null,