Modify metric api as per offline feebacks (#326)

* Modify metric api as per offline feebacks

* FileName change

* fix missing measure methods on Meter

* fix no op meter

src/OpenTelemetry.Api/Metrics/Counter.cs

@@ -0,0 +1,59 @@
+// <copyright file="Counter.cs" company="OpenTelemetry Authors">
+// Copyright 2018, OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+// </copyright>
+
+using System.Collections.Generic;
+using OpenTelemetry.Trace;
+
+namespace OpenTelemetry.Metrics
+{
+    /// <summary>
+    /// Counter instrument.
+    /// </summary>
+    /// <typeparam name="T">The type of counter. Only long and double are supported now.</typeparam>
+    public abstract class Counter<T>
+        where T : struct
+    {
+        /// <summary>
+        /// Adds or Increments the counter.
+        /// </summary>
+        /// <param name="context">the associated span context.</param>
+        /// <param name="value">value by which the counter should be incremented.</param>
+        /// <param name="labelset">The labelset associated with this value.</param>
+        public abstract void Add(in SpanContext context, T value, LabelSet labelset);
+
+        /// <summary>
+        /// Adds or Increments the counter.
+        /// </summary>
+        /// <param name="context">the associated span context.</param>
+        /// <param name="value">value by which the counter should be incremented.</param>
+        /// <param name="labels">The labels or dimensions associated with this value.</param>
+        public abstract void Add(in SpanContext context, T value, IEnumerable<KeyValuePair<string, string>> labels);
+
+        /// <summary>
+        /// Gets the handle with given labelset.
+        /// </summary>
+        /// <param name="labelset">The labelset from which handle should be constructed.</param>
+        /// <returns>The handle.</returns>
+        public abstract CounterHandle<T> GetHandle(LabelSet labelset);
+
+        /// <summary>
+        /// Gets the handle with given labels.
+        /// </summary>
+        /// <param name="labels">The labels or dimensions associated with this value.</param>
+        /// <returns>The handle.</returns>
+        public abstract CounterHandle<T> GetHandle(IEnumerable<KeyValuePair<string, string>> labels);
+    }
+}

src/OpenTelemetry.Api/Metrics/CounterHandle.cs

@@ -1,4 +1,4 @@
-// <copyright file="ICounterHandle.cs" company="OpenTelemetry Authors">
+// <copyright file="CounterHandle.cs" company="OpenTelemetry Authors">
 // Copyright 2018, OpenTelemetry Authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
@@ -14,17 +14,24 @@
 // limitations under the License.
 // </copyright>
 
+using OpenTelemetry.Trace;
+
 namespace OpenTelemetry.Metrics
 {
     /// <summary>
     /// Handle to the counter with the defined <see cref="LabelSet"/>.
     /// </summary>
-    public interface ICounterHandle
+    /// <typeparam name="T">The type of counter. Only long and double are supported now.</typeparam>
+    public struct CounterHandle<T>
+        where T : struct
     {
         /// <summary>
         /// Adds or Increments the value of the counter handle.
         /// </summary>
+        /// <param name="context">the associated span context.</param>
         /// <param name="value">value by which the counter handle should be incremented.</param>
-        void Add(int value);
+        public void Add(in SpanContext context, T value)
+        {
+        }
     }
 }

src/OpenTelemetry.Api/Metrics/Guage.cs

@@ -0,0 +1,59 @@
+// <copyright file="Guage.cs" company="OpenTelemetry Authors">
+// Copyright 2018, OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+// </copyright>
+
+using System.Collections.Generic;
+using OpenTelemetry.Trace;
+
+namespace OpenTelemetry.Metrics
+{
+    /// <summary>
+    /// Gauge instrument.
+    /// </summary>
+    /// <typeparam name="T">The type of gauge. Only long and double are supported now.</typeparam>
+    public abstract class Guage<T>
+        where T : struct
+    {
+        /// <summary>
+        /// Sets the value of the guague.
+        /// </summary>
+        /// <param name="context">the associated span context.</param>
+        /// <param name="value">value to which the Gauge should be set.</param>
+        /// <param name="labelset">The labelset associated with this value.</param>
+        public abstract void Set(in SpanContext context, T value, LabelSet labelset);
+
+        /// <summary>
+        /// Sets the guague.
+        /// </summary>
+        /// <param name="context">the associated span context.</param>
+        /// <param name="value">value to which the Gauge should be set.</param>
+        /// <param name="labels">The labels or dimensions associated with this value.</param>
+        public abstract void Set(in SpanContext context, T value, IEnumerable<KeyValuePair<string, string>> labels);
+
+        /// <summary>
+        /// Gets the handle with given labelset.
+        /// </summary>
+        /// <param name="labelset">The labelset from which handle should be constructed.</param>
+        /// <returns>The handle.</returns>
+        public abstract CounterHandle<T> GetHandle(LabelSet labelset);
+
+        /// <summary>
+        /// Gets the handle with given labels.
+        /// </summary>
+        /// <param name="labels">The labels or dimensions associated with this value.</param>
+        /// <returns>The handle.</returns>
+        public abstract CounterHandle<T> GetHandle(IEnumerable<KeyValuePair<string, string>> labels);
+    }
+}

src/OpenTelemetry.Api/Metrics/GuageHandle.cs

@@ -1,4 +1,4 @@
-// <copyright file="IGuageHandle.cs" company="OpenTelemetry Authors">
+// <copyright file="GuageHandle.cs" company="OpenTelemetry Authors">
 // Copyright 2018, OpenTelemetry Authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
@@ -14,17 +14,27 @@
 // limitations under the License.
 // </copyright>
 
+using OpenTelemetry.Trace;
+
 namespace OpenTelemetry.Metrics
 {
     /// <summary>
     /// Handle to the gauge with the defined <see cref="LabelSet"/>.
     /// </summary>
-    public interface IGuageHandle
+    /// <typeparam name="T">The type of the Gauge. Only long and double are supported now.</typeparam>
+    public struct GuageHandle<T>
+        where T : struct
     {
         /// <summary>
         /// Sets the value of the guague.
         /// </summary>
-        /// <param name="value">value to set the guage to.</param>
-        void Set(int value);
+        /// <summary>
+        /// Sets the value of the guague handle.
+        /// </summary>
+        /// <param name="context">the associated span context.</param>
+        /// <param name="value">value to which the Gauge should be set.</param>
+        public void Set(in SpanContext context, T value)
+        {
+        }
     }
 }

src/OpenTelemetry.Api/Metrics/ICounter.cs

@@ -1,38 +0,0 @@
-// <copyright file="ICounter.cs" company="OpenTelemetry Authors">
-// Copyright 2018, OpenTelemetry Authors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-// </copyright>
-
-namespace OpenTelemetry.Metrics
-{
-    /// <summary>
-    /// Counter instrument.
-    /// </summary>
-    public interface ICounter
-    {
-        /// <summary>
-        /// Adds or Increments the counter.
-        /// </summary>
-        /// <param name="value">value by which the counter should be incremented.</param>
-        /// <param name="labelset">The labelset associated with this value.</param>
-        void Add(int value, LabelSet labelset);
-
-        /// <summary>
-        /// Gets the handle with given labelset.
-        /// </summary>
-        /// <param name="labelset">The labelset from which handle should be constructed.</param>
-        /// <returns>The <see cref="ICounterHandle" /> with label.</returns>
-        ICounterHandle GetHandle(LabelSet labelset);
-    }
-}

src/OpenTelemetry.Api/Metrics/IGuage.cs

@@ -1,38 +0,0 @@
-// <copyright file="IGuage.cs" company="OpenTelemetry Authors">
-// Copyright 2018, OpenTelemetry Authors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-// </copyright>
-
-namespace OpenTelemetry.Metrics
-{
-    /// <summary>
-    /// Gauge instrument.
-    /// </summary>
-    public interface IGuage
-    {
-        /// <summary>
-        /// Sets the value of the guague.
-        /// </summary>
-        /// <param name="value">value by which the counter should be incremented.</param>
-        /// <param name="labelset">The labelset associated with this value.</param>
-        void Set(int value, LabelSet labelset);
-
-        /// <summary>
-        /// Gets the handle with given labelset.
-        /// </summary>
-        /// <param name="labelset">The labelset from which handle should be constructed.</param>
-        /// <returns>The <see cref="IGuageHandle" /> with label.</returns>
-        IGuageHandle GetHandle(LabelSet labelset);
-    }
-}

src/OpenTelemetry.Api/Metrics/IMeasure.cs

@@ -1,38 +0,0 @@
-// <copyright file="IMeasure.cs" company="OpenTelemetry Authors">
-// Copyright 2018, OpenTelemetry Authors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-// </copyright>
-
-namespace OpenTelemetry.Metrics
-{
-    /// <summary>
-    /// Measure instrument.
-    /// </summary>
-    public interface IMeasure
-    {
-        /// <summary>
-        /// Records a measure.
-        /// </summary>
-        /// <param name="value">value by which the counter should be incremented.</param>
-        /// <param name="labelset">The labelset associated with this value.</param>
-        void Record(int value, LabelSet labelset);
-
-        /// <summary>
-        /// Gets the handle with given labelset.
-        /// </summary>
-        /// <param name="labelset">The labelset from which handle should be constructed.</param>
-        /// <returns>The <see cref="IMeasureHandle" /> with label.</returns>
-        IMeasureHandle GetHandle(LabelSet labelset);
-    }
-}

src/OpenTelemetry.Api/Metrics/IMeter.cs

@@ -1,54 +0,0 @@
-// <copyright file="IMeter.cs" company="OpenTelemetry Authors">
-// Copyright 2018, OpenTelemetry Authors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-// </copyright>
-
-using System.Collections.Generic;
-
-namespace OpenTelemetry.Metrics
-{
-    /// <summary>
-    /// Main interface to obtain metric instruments.
-    /// </summary>
-    public interface IMeter
-    {
-        /// <summary>
-        /// Creates a <see cref="ICounter"/> with given name.
-        /// </summary>
-        /// <param name="name">The name of the <see cref="ICounter"/>.</param>
-        /// <returns>The <see cref="ICounter"/> instance.</returns>
-        ICounter CreateCounter(string name);
-
-        /// <summary>
-        /// Creates a <see cref="IGuage"/> with given name.
-        /// </summary>
-        /// <param name="name">The name of the <see cref="IGuage"/>.</param>
-        /// <returns>The <see cref="IGuage"/> instance.</returns>
-        IGuage CreateGauge(string name);
-
-        /// <summary>
-        /// Creates a <see cref="IMeasure"/> with given name.
-        /// </summary>
-        /// <param name="name">The name of the <see cref="IMeasure"/>.</param>
-        /// <returns>The <see cref="IMeasure"/> instance.</returns>
-        IMeasure CreateMeasure(string name);
-
-        /// <summary>
-        /// Constructs or retrieves the <see cref="LabelSet"/> from the given label key-value pairs.
-        /// </summary>
-        /// <param name="labels">Label key value pairs.</param>
-        /// <returns>The <see cref="LabelSet"/> with given label key value pairs.</returns>
-        LabelSet GetLabelSet(IEnumerable<KeyValuePair<string, string>> labels);
-    }
-}

src/OpenTelemetry.Api/Metrics/LabelSet.cs

@@ -16,7 +16,7 @@
 namespace OpenTelemetry.Metrics
 {
     /// <summary>
-    /// Name value pairs of metric labels.
+    /// Normalized name value pairs of metric labels.
     /// </summary>
     public class LabelSet
     {

src/OpenTelemetry.Api/Metrics/Measure.cs

@@ -0,0 +1,59 @@
+// <copyright file="Measure.cs" company="OpenTelemetry Authors">
+// Copyright 2018, OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+// </copyright>
+
+using System.Collections.Generic;
+using OpenTelemetry.Trace;
+
+namespace OpenTelemetry.Metrics
+{
+    /// <summary>
+    /// Measure instrument.
+    /// </summary>
+    /// <typeparam name="T">The type of counter. Only long and double are supported now.</typeparam>
+    public abstract class Measure<T>
+        where T : struct
+    {
+        /// <summary>
+        /// Records a measure.
+        /// </summary>
+        /// <param name="context">the associated span context.</param>
+        /// <param name="value">value to record.</param>
+        /// <param name="labelset">The labelset associated with this value.</param>
+        public abstract void Record(in SpanContext context, T value, LabelSet labelset);
+
+        /// <summary>
+        /// Records a measure.
+        /// </summary>
+        /// <param name="context">the associated span context.</param>
+        /// <param name="value">value to record.</param>
+        /// <param name="labels">The labels or dimensions associated with this value.</param>
+        public abstract void Record(in SpanContext context, int value, IEnumerable<KeyValuePair<string, string>> labels);
+
+        /// <summary>
+        /// Gets the handle with given labelset.
+        /// </summary>
+        /// <param name="labelset">The labelset from which handle should be constructed.</param>
+        /// <returns>The handle.</returns>
+        public abstract MeasureHandle<T> GetHandle(LabelSet labelset);
+
+        /// <summary>
+        /// Gets the handle with given labelset.
+        /// </summary>
+        /// <param name="labels">The labels or dimensions associated with this value.</param>
+        /// <returns>The handle.</returns>
+        public abstract MeasureHandle<T> GetHandle(IEnumerable<KeyValuePair<string, string>> labels);
+    }
+}

src/OpenTelemetry.Api/Metrics/MeasureHandle.cs

@@ -1,4 +1,4 @@
-// <copyright file="IMeasureHandle.cs" company="OpenTelemetry Authors">
+// <copyright file="MeasureHandle.cs" company="OpenTelemetry Authors">
 // Copyright 2018, OpenTelemetry Authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
@@ -14,17 +14,27 @@
 // limitations under the License.
 // </copyright>
 
+using OpenTelemetry.Trace;
+
 namespace OpenTelemetry.Metrics
 {
     /// <summary>
     /// Handle to the measure with the defined <see cref="LabelSet"/>.
     /// </summary>
-    public interface IMeasureHandle
+    /// <typeparam name="T">The type of the Measure. Only long and double are supported now.</typeparam>
+    public struct MeasureHandle<T>
+        where T : struct
     {
         /// <summary>
         /// Records a measure.
         /// </summary>
+        /// <summary>
+        /// Sets the value of the guague handle.
+        /// </summary>
+        /// <param name="context">the associated span context.</param>
         /// <param name="value">value to record.</param>
-        void Record(int value);
+        public void Record(in SpanContext context, T value)
+        {
+        }
     }
 }

src/OpenTelemetry.Api/Metrics/Meter.cs

@@ -0,0 +1,81 @@
+// <copyright file="Meter.cs" company="OpenTelemetry Authors">
+// Copyright 2018, OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+// </copyright>
+
+using System.Collections.Generic;
+
+namespace OpenTelemetry.Metrics
+{
+    /// <summary>
+    /// Main interface to obtain metric instruments.
+    /// </summary>
+    public abstract class Meter
+    {
+        /// <summary>
+        /// Creates a counter for long with given name.
+        /// </summary>
+        /// <param name="name">The name of the counter.</param>
+        /// <param name="monotonic">indicates if only positive values are expected.</param>
+        /// <returns>The counter instance.</returns>
+        public abstract Counter<long> CreateLongCounter(string name, bool monotonic = true);
+
+        /// <summary>
+        /// Creates a counter for double with given name.
+        /// </summary>
+        /// <param name="name">indicates if only positive values are expected.</param>
+        /// <param name="monotonic">The name of the counter.</param>
+        /// <returns>The counter instance.</returns>
+        public abstract Counter<double> CreateDoubleCounter(string name, bool monotonic = true);
+
+        /// <summary>
+        /// Creates a guage for long with given name.
+        /// </summary>
+        /// <param name="name">The name of the counter.</param>
+        /// <param name="monotonic">indicates if only positive values are expected.</param>
+        /// <returns>The guage instance.</returns>
+        public abstract Guage<long> CreateLongGauge(string name, bool monotonic = false);
+
+        /// <summary>
+        /// Creates a guage for long with given name.
+        /// </summary>
+        /// <param name="name">The name of the counter.</param>
+        /// <param name="monotonic">indicates if only positive values are expected.</param>
+        /// <returns>The guage instance.</returns>
+        public abstract Guage<double> CreateDoubleGauge(string name, bool monotonic = false);
+
+        /// <summary>
+        /// Creates a measure for long with given name.
+        /// </summary>
+        /// <param name="name">The name of the measure.</param>
+        /// <param name="absolute">indicates if only positive values are expected.</param>
+        /// <returns>The measure instance.</returns>
+        public abstract Measure<long> CreateLongMeasure(string name, bool absolute = true);
+
+        /// <summary>
+        /// Creates a measure for long with given name.
+        /// </summary>
+        /// <param name="name">The name of the measure.</param>
+        /// <param name="absolute">indicates if only positive values are expected.</param>
+        /// <returns>The measure instance.</returns>
+        public abstract Measure<double> CreateDoubleMeasure(string name, bool absolute = true);
+
+        /// <summary>
+        /// Constructs or retrieves the <see cref="LabelSet"/> from the given label key-value pairs.
+        /// </summary>
+        /// <param name="labels">Label key value pairs.</param>
+        /// <returns>The <see cref="LabelSet"/> with given label key value pairs.</returns>
+        public abstract LabelSet GetLabelSet(IEnumerable<KeyValuePair<string, string>> labels);
+    }
+}

src/OpenTelemetry.Api/Metrics/MeterFactoryBase.cs

@@ -20,6 +20,7 @@ namespace OpenTelemetry.Metrics
     /// </summary>
     public class MeterFactoryBase
     {
+        private static NoOpMeter noOpMeter = new NoOpMeter();
         private static MeterFactoryBase defaultFactory = new MeterFactoryBase();
 
         /// <summary>
@@ -33,11 +34,12 @@ namespace OpenTelemetry.Metrics
         /// <summary>
         /// Returns an IMeter for a given name and version.
         /// </summary>
-        /// <param name="componentName">Name of the instrumentation library or component this Metric is meant for.</param>
-        /// <returns>Meter with the given component name.</returns>
-        public virtual IMeter GetMeter(string componentName)
+        /// <param name="name">Name of the instrumentation library.</param>
+        /// <param name="version">Version of the instrumentation library (optional).</param>
+        /// <returns>Meter with the given component name and version.</returns>
+        public virtual Meter GetMeter(string name, string version = null)
         {
-            return defaultFactory.GetMeter(componentName);
+            return noOpMeter;
         }
     }
 }

src/OpenTelemetry.Api/Metrics/NoOpMeter.cs

@@ -0,0 +1,66 @@
+// <copyright file="NoOpMeter.cs" company="OpenTelemetry Authors">
+// Copyright 2018, OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+// </copyright>
+using System.Collections.Generic;
+
+namespace OpenTelemetry.Metrics
+{
+    internal sealed class NoOpMeter : Meter
+    {
+        public NoOpMeter()
+        {
+        }
+
+        public override Counter<double> CreateDoubleCounter(string name, bool monotonic = true)
+        {
+            // return no op
+            throw new System.NotImplementedException();
+        }
+
+        public override Guage<double> CreateDoubleGauge(string name, bool monotonic = false)
+        {
+            // return no op
+            throw new System.NotImplementedException();
+        }
+
+        public override Measure<double> CreateDoubleMeasure(string name, bool absolute = true)
+        {
+            throw new System.NotImplementedException();
+        }
+
+        public override Counter<long> CreateLongCounter(string name, bool monotonic = true)
+        {
+            // return no op
+            throw new System.NotImplementedException();
+        }
+
+        public override Guage<long> CreateLongGauge(string name, bool monotonic = false)
+        {
+            // return no op
+            throw new System.NotImplementedException();
+        }
+
+        public override Measure<long> CreateLongMeasure(string name, bool absolute = true)
+        {
+            throw new System.NotImplementedException();
+        }
+
+        public override LabelSet GetLabelSet(IEnumerable<KeyValuePair<string, string>> labels)
+        {
+            // return no op
+            throw new System.NotImplementedException();
+        }
+    }
+}