Make suppress instrumentation APIs less prone to introducing bugs

docs/trace/building-your-own-exporter/MyExporter.cs

@@ -31,7 +31,7 @@ public override Task<ExportResult> ExportAsync(
         // telemetry should do so inside SuppressInstrumentation
         // scope. This suppresses telemetry from
         // exporter's own code to avoid live-loop situation.
-        using var scope = Sdk.SuppressInstrumentation.Begin();
+        using var scope = SuppressInstrumentationScope.Begin();
 
         foreach (var activity in batch)
         {

src/OpenTelemetry/CHANGELOG.md

@@ -12,7 +12,8 @@
   match the spec
   ([#1013](https://github.com/open-telemetry/opentelemetry-dotnet/pull/1013))
 * Added `SuppressInstrumentationScope` API
-  ([#988](https://github.com/open-telemetry/opentelemetry-dotnet/pull/988))
+  ([#988](https://github.com/open-telemetry/opentelemetry-dotnet/pull/988)
+  [#1067](https://github.com/open-telemetry/opentelemetry-dotnet/pull/1067))
 * Changed `BroadcastActivityProcessor` to `FanOutActivityProcessor`
   ([#1015](https://github.com/open-telemetry/opentelemetry-dotnet/pull/1015))
 * Changed `TracerProviderBuilder` and `TracerProviderSdk` design to simply the

src/OpenTelemetry/Sdk.cs

@@ -29,10 +29,13 @@ namespace OpenTelemetry
     /// </summary>
     public static class Sdk
     {
-        public static readonly SuppressInstrumentationScope SuppressInstrumentation = new SuppressInstrumentationScope(false);
-
         private static readonly TimeSpan DefaultPushInterval = TimeSpan.FromSeconds(60);
 
+        /// <summary>
+        /// Gets a value indicating whether instrumentation is suppressed (disabled).
+        /// </summary>
+        public static bool SuppressInstrumentation => SuppressInstrumentationScope.IsSuppressed;
+
         /// <summary>
         /// Creates MeterProvider with the configuration provided.
         /// Configuration involves MetricProcessor, Exporter and push internval.

src/OpenTelemetry/SuppressInstrumentationScope.cs

@@ -32,7 +32,7 @@ internal SuppressInstrumentationScope(bool value = true)
             Slot.Set(value);
         }
 
-        public static implicit operator bool(SuppressInstrumentationScope unused) => Slot.Get();
+        internal static bool IsSuppressed => Slot.Get();
 
         /// <summary>
         /// Begins a new scope in which instrumentation is suppressed (disabled).
@@ -43,20 +43,20 @@ internal SuppressInstrumentationScope(bool value = true)
         /// This is typically used to prevent infinite loops created by
         /// collection of internal operations, such as exporting traces over HTTP.
         /// <code>
-        ///    public override async Task&lt;ExportResult&gt; ExportAsync(
-        ///        IEnumerable&lt;Activity&gt; batch,
-        ///        CancellationToken cancellationToken)
-        ///    {
-        ///       using (Sdk.SuppressInstrumentation.Begin())
-        ///       {
-        ///           // Instrumentation is suppressed (i.e., Sdk.SuppressInstrumentation == true)
-        ///       }
+        ///     public override async Task&lt;ExportResult&gt; ExportAsync(
+        ///         IEnumerable&lt;Activity&gt; batch,
+        ///         CancellationToken cancellationToken)
+        ///     {
+        ///         using (SuppressInstrumentationScope.Begin())
+        ///         {
+        ///             // Instrumentation is suppressed (i.e., Sdk.SuppressInstrumentation == true)
+        ///         }
         ///
-        ///       // Instrumentation is not suppressed (i.e., Sdk.SuppressInstrumentation == false)
-        ///    }
+        ///         // Instrumentation is not suppressed (i.e., Sdk.SuppressInstrumentation == false)
+        ///     }
         /// </code>
         /// </remarks>
-        public IDisposable Begin(bool value = true)
+        public static IDisposable Begin(bool value = true)
         {
             return new SuppressInstrumentationScope(value);
         }

test/OpenTelemetry.Tests/SuppressInstrumentationTest.cs

@@ -23,11 +23,13 @@ public class SuppressInstrumentationTest
         [Fact]
         public static void UsingSuppressInstrumentation()
         {
-            using (var scope = Sdk.SuppressInstrumentation.Begin())
+            Assert.False(Sdk.SuppressInstrumentation);
+
+            using (var scope = SuppressInstrumentationScope.Begin())
             {
                 Assert.True(Sdk.SuppressInstrumentation);
 
-                using (var innerScope = Sdk.SuppressInstrumentation.Begin())
+                using (var innerScope = SuppressInstrumentationScope.Begin())
                 {
                     innerScope.Dispose();