Metrics are obsolete

examples/Console/Examples.Console.csproj

@@ -4,6 +4,7 @@
     <OutputType>Exe</OutputType>
     <TargetFramework>netcoreapp3.1</TargetFramework>
     <IsPackable>false</IsPackable>
+    <NoWarn>$(NoWarn),CS0618</NoWarn>
   </PropertyGroup>
 
   <ItemGroup>

src/OpenTelemetry.Api/CHANGELOG.md

@@ -8,6 +8,12 @@
   extension) will now be set as the `Unset`, `Error`, or `Ok` string
   representation instead of the `0`, `1`, or `2` integer representation.
   ([#1579](https://github.com/open-telemetry/opentelemetry-dotnet/pull/1579))
+* Metrics API/SDK support is in an experimental state and is not recommended for
+  production use. All metric APIs have been marked with the `Obsolete`
+  attribute. See
+  [#1501](https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501)
+  for more information.
+  ([#1611](https://github.com/open-telemetry/opentelemetry-dotnet/pull/1611))
 
 ## 1.0.0-rc1.1
 

src/OpenTelemetry.Api/Metrics/BlankLabelSet.cs

@@ -14,11 +14,14 @@
 // limitations under the License.
 // </copyright>
 
+using System;
+
 namespace OpenTelemetry.Metrics
 {
     /// <summary>
     /// Blank or No-op labelset.
     /// </summary>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public sealed class BlankLabelSet : LabelSet
     {
     }

src/OpenTelemetry.Api/Metrics/BoundCounterMetric.cs

@@ -14,6 +14,7 @@
 // limitations under the License.
 // </copyright>
 
+using System;
 using OpenTelemetry.Trace;
 
 namespace OpenTelemetry.Metrics
@@ -22,6 +23,7 @@ namespace OpenTelemetry.Metrics
     /// Bound counter metric with the defined <see cref="LabelSet"/>.
     /// </summary>
     /// <typeparam name="T">The type of counter. Only long and double are supported now.</typeparam>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public abstract class BoundCounterMetric<T>
         where T : struct
     {

src/OpenTelemetry.Api/Metrics/BoundMeasureMetric.cs

@@ -14,6 +14,7 @@
 // limitations under the License.
 // </copyright>
 
+using System;
 using OpenTelemetry.Trace;
 
 namespace OpenTelemetry.Metrics
@@ -22,6 +23,7 @@ namespace OpenTelemetry.Metrics
     /// Bound measure metric with the defined <see cref="LabelSet"/>.
     /// </summary>
     /// <typeparam name="T">The type of Measure. Only long and double are supported now.</typeparam>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public abstract class BoundMeasureMetric<T>
         where T : struct
     {

src/OpenTelemetry.Api/Metrics/CounterMetric.cs

@@ -14,6 +14,7 @@
 // limitations under the License.
 // </copyright>
 
+using System;
 using System.Collections.Generic;
 using OpenTelemetry.Trace;
 
@@ -23,6 +24,7 @@ namespace OpenTelemetry.Metrics
     /// Counter instrument.
     /// </summary>
     /// <typeparam name="T">The type of counter. Only long and double are supported now.</typeparam>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public abstract class CounterMetric<T>
         where T : struct
     {

src/OpenTelemetry.Api/Metrics/DoubleObserverMetric.cs

@@ -14,13 +14,15 @@
 // limitations under the License.
 // </copyright>
 
+using System;
 using System.Collections.Generic;
 
 namespace OpenTelemetry.Metrics
 {
     /// <summary>
     /// Observer instrument for Double values.
     /// </summary>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public abstract class DoubleObserverMetric
     {
         /// <summary>

src/OpenTelemetry.Api/Metrics/DoubleObserverMetricHandle.cs

@@ -14,11 +14,14 @@
 // limitations under the License.
 // </copyright>
 
+using System;
+
 namespace OpenTelemetry.Metrics
 {
     /// <summary>
     /// Handle to the metrics observer with the defined <see cref="LabelSet"/>.
     /// </summary>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public abstract class DoubleObserverMetricHandle
     {
         /// <summary>

src/OpenTelemetry.Api/Metrics/Int64ObserverMetric.cs

@@ -14,13 +14,15 @@
 // limitations under the License.
 // </copyright>
 
+using System;
 using System.Collections.Generic;
 
 namespace OpenTelemetry.Metrics
 {
     /// <summary>
     /// Observer instrument for Int64 values.
     /// </summary>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public abstract class Int64ObserverMetric
     {
         /// <summary>

src/OpenTelemetry.Api/Metrics/Int64ObserverMetricHandle.cs

@@ -14,11 +14,14 @@
 // limitations under the License.
 // </copyright>
 
+using System;
+
 namespace OpenTelemetry.Metrics
 {
     /// <summary>
     /// Handle to the metrics observer with the defined <see cref="LabelSet"/>.
     /// </summary>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public abstract class Int64ObserverMetricHandle
     {
         /// <summary>

src/OpenTelemetry.Api/Metrics/LabelSet.cs

@@ -13,6 +13,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 // </copyright>
+
+using System;
 using System.Collections.Generic;
 using System.Linq;
 
@@ -21,6 +23,7 @@ namespace OpenTelemetry.Metrics
     /// <summary>
     /// Normalized name value pairs of metric labels.
     /// </summary>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public abstract class LabelSet
     {
         /// <summary>

src/OpenTelemetry.Api/Metrics/MeasureMetric.cs

@@ -14,6 +14,7 @@
 // limitations under the License.
 // </copyright>
 
+using System;
 using System.Collections.Generic;
 using OpenTelemetry.Trace;
 
@@ -23,6 +24,7 @@ namespace OpenTelemetry.Metrics
     /// Measure instrument.
     /// </summary>
     /// <typeparam name="T">The type of measure. Only long and double are supported now.</typeparam>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public abstract class MeasureMetric<T>
         where T : struct
     {

src/OpenTelemetry.Api/Metrics/Meter.cs

@@ -22,6 +22,7 @@ namespace OpenTelemetry.Metrics
     /// <summary>
     /// Main interface to obtain metric instruments.
     /// </summary>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public abstract class Meter
     {
         /// <summary>

src/OpenTelemetry.Api/Metrics/MeterFactoryBase.cs

@@ -22,6 +22,7 @@ namespace OpenTelemetry.Metrics
     /// Libraries should use this class as follows to obtain Meter instance.
     /// MeterFactoryBase.Default.GetMeter("libraryname", "version").
     /// </summary>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public class MeterFactoryBase
     {
         private static ProxyMeter proxyMeter = new ProxyMeter();

src/OpenTelemetry.Api/Metrics/MeterProvider.cs

@@ -21,6 +21,7 @@ namespace OpenTelemetry.Metrics
     /// <summary>
     /// MeterProvider is the entry point of the OpenTelemetry Metrics API. It provides access to Meters.
     /// </summary>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public class MeterProvider : BaseProvider
     {
         private static ProxyMeter proxyMeter = new ProxyMeter();

src/OpenTelemetry.Api/Metrics/NoopBoundCounterMetric.cs

@@ -14,6 +14,7 @@
 // limitations under the License.
 // </copyright>
 
+using System;
 using OpenTelemetry.Trace;
 
 namespace OpenTelemetry.Metrics
@@ -22,6 +23,7 @@ namespace OpenTelemetry.Metrics
     /// No-Op bound counter metric.
     /// </summary>
     /// <typeparam name="T">The type of counter. Only long and double are supported now.</typeparam>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public sealed class NoopBoundCounterMetric<T> : BoundCounterMetric<T>
         where T : struct
     {

src/OpenTelemetry.Api/Metrics/NoopBoundMeasureMetric.cs

@@ -14,6 +14,7 @@
 // limitations under the License.
 // </copyright>
 
+using System;
 using OpenTelemetry.Trace;
 
 namespace OpenTelemetry.Metrics
@@ -22,6 +23,7 @@ namespace OpenTelemetry.Metrics
     /// No op measure handle.
     /// </summary>
     /// <typeparam name="T">The type of Measure. Only long and double are supported now.</typeparam>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public sealed class NoopBoundMeasureMetric<T> : BoundMeasureMetric<T>
         where T : struct
     {

src/OpenTelemetry.Api/Metrics/NoopCounterMetric.cs

@@ -14,6 +14,7 @@
 // limitations under the License.
 // </copyright>
 
+using System;
 using System.Collections.Generic;
 using OpenTelemetry.Trace;
 
@@ -23,6 +24,7 @@ namespace OpenTelemetry.Metrics
     /// A no-op counter instrument.
     /// </summary>
     /// <typeparam name="T">The type of counter. Only long and double are supported now.</typeparam>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public sealed class NoopCounterMetric<T> : CounterMetric<T>
         where T : struct
     {

src/OpenTelemetry.Api/Metrics/NoopDoubleObserverMetric.cs

@@ -14,13 +14,15 @@
 // limitations under the License.
 // </copyright>
 
+using System;
 using System.Collections.Generic;
 
 namespace OpenTelemetry.Metrics
 {
     /// <summary>
     /// A no-op observer instrument.
     /// </summary>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public sealed class NoopDoubleObserverMetric : DoubleObserverMetric
     {
         /// <summary>

src/OpenTelemetry.Api/Metrics/NoopDoubleObserverMetricHandle.cs

@@ -14,11 +14,14 @@
 // limitations under the License.
 // </copyright>
 
+using System;
+
 namespace OpenTelemetry.Metrics
 {
     /// <summary>
     /// No-Op observer handle.
     /// </summary>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public sealed class NoopDoubleObserverMetricHandle : DoubleObserverMetricHandle
     {
         /// <summary>

src/OpenTelemetry.Api/Metrics/NoopInt64ObserverMetric.cs

@@ -14,13 +14,15 @@
 // limitations under the License.
 // </copyright>
 
+using System;
 using System.Collections.Generic;
 
 namespace OpenTelemetry.Metrics
 {
     /// <summary>
     /// A no-op observer instrument.
     /// </summary>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public sealed class NoopInt64ObserverMetric : Int64ObserverMetric
     {
         /// <summary>

src/OpenTelemetry.Api/Metrics/NoopInt64ObserverMetricHandle.cs

@@ -14,11 +14,14 @@
 // limitations under the License.
 // </copyright>
 
+using System;
+
 namespace OpenTelemetry.Metrics
 {
     /// <summary>
     /// No-Op observer handle.
     /// </summary>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public sealed class NoopInt64ObserverMetricHandle : Int64ObserverMetricHandle
     {
         /// <summary>

src/OpenTelemetry.Api/Metrics/NoopMeasureMetric.cs

@@ -14,6 +14,7 @@
 // limitations under the License.
 // </copyright>
 
+using System;
 using System.Collections.Generic;
 
 namespace OpenTelemetry.Metrics
@@ -22,6 +23,7 @@ namespace OpenTelemetry.Metrics
     /// No op measure instrument.
     /// </summary>
     /// <typeparam name="T">The type of counter. Only long and double are supported now.</typeparam>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public sealed class NoopMeasureMetric<T> : MeasureMetric<T>
         where T : struct
     {

src/OpenTelemetry.Api/OpenTelemetry.Api.csproj

@@ -3,6 +3,8 @@
     <TargetFrameworks>net452;netstandard2.0</TargetFrameworks>
     <Description>OpenTelemetry .NET API</Description>
     <RootNamespace>OpenTelemetry</RootNamespace>
+
+    <NoWarn>$(NoWarn),CS0618</NoWarn>
   </PropertyGroup>
 
   <ItemGroup>

src/OpenTelemetry.Exporter.Prometheus/OpenTelemetry.Exporter.Prometheus.csproj

@@ -3,6 +3,7 @@
     <TargetFrameworks>net452;net46;netstandard2.0</TargetFrameworks>
     <Description>Prometheus exporter for OpenTelemetry .NET</Description>
     <PackageTags>$(PackageTags);Prometheus</PackageTags>
+    <NoWarn>$(NoWarn),CS0618</NoWarn>
   </PropertyGroup>
 
   <ItemGroup>

src/OpenTelemetry/CHANGELOG.md

@@ -7,6 +7,12 @@
   `AddEnvironmentVariableDetector`, `AddAttributes`, `AddService`, and
   `AddTelemetrySdk`.
   ([#1576](https://github.com/open-telemetry/opentelemetry-dotnet/pull/1576))
+* Metrics API/SDK support is in an experimental state and is not recommended for
+  production use. All metric APIs have been marked with the `Obsolete`
+  attribute. See
+  [#1501](https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501)
+  for more information.
+  ([#1611](https://github.com/open-telemetry/opentelemetry-dotnet/pull/1611))
 
 ## 1.0.0-rc1.1
 

src/OpenTelemetry/Metrics/Aggregators/Aggregator.cs

@@ -24,6 +24,7 @@ namespace OpenTelemetry.Metrics.Aggregators
     /// Aggregator base class.
     /// </summary>
     /// <typeparam name="T">The type.</typeparam>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public abstract class Aggregator<T>
         where T : struct
     {

src/OpenTelemetry/Metrics/Aggregators/DoubleCounterSumAggregator.cs

@@ -23,6 +23,7 @@ namespace OpenTelemetry.Metrics.Aggregators
     /// <summary>
     /// Basic aggregator which calculates a Sum from individual measurements.
     /// </summary>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public class DoubleCounterSumAggregator : Aggregator<double>
     {
         private double sum;

src/OpenTelemetry/Metrics/Aggregators/DoubleLastValueAggregator.cs

@@ -23,6 +23,7 @@ namespace OpenTelemetry.Metrics.Aggregators
     /// <summary>
     /// Simple aggregator that only keeps the last value.
     /// </summary>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public class DoubleLastValueAggregator : Aggregator<double>
     {
         private double value;

src/OpenTelemetry/Metrics/Aggregators/DoubleMeasureMinMaxSumCountAggregator.cs

@@ -23,6 +23,7 @@ namespace OpenTelemetry.Metrics.Aggregators
     /// <summary>
     /// Aggregator which calculates summary (Min,Max,Sum,Count) from measures.
     /// </summary>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public class DoubleMeasureMinMaxSumCountAggregator : Aggregator<double>
     {
         private DoubleSummary summary = new DoubleSummary();

src/OpenTelemetry/Metrics/Aggregators/Int64CounterSumAggregator.cs

@@ -23,6 +23,7 @@ namespace OpenTelemetry.Metrics.Aggregators
     /// <summary>
     /// Basic aggregator which calculates a Sum from individual measurements.
     /// </summary>
+    [Obsolete("Metrics API/SDK is not recommended for production. See https://github.com/open-telemetry/opentelemetry-dotnet/issues/1501 for more information on metrics support.")]
     public class Int64CounterSumAggregator : Aggregator<long>
     {
         private long sum;