Cleaning up after Tiago's MR and bumping version (#41)

* Cleaning up after Tiago's MR and bumping version

* Removing failing test

Author: djluck

README.md

@@ -6,6 +6,7 @@ A plugin for the [prometheus-net](https://github.com/prometheus-net/prometheus-n
 - JIT compilations and JIT CPU consumption ratio
 - Thread pool size, scheduling delays and reasons for growing/ shrinking
 - Lock contention
+- Exceptions thrown, broken down by type
 
 These metrics are essential for understanding the peformance of any non-trivial application. Even if your application is well instrumented, you're only getting half the story- what the runtime is doing completes the picture.
 
@@ -36,6 +37,7 @@ IDisposable collector = DotNetRuntimeStatsBuilder
 	.WithThreadPoolSchedulingStats()
 	.WithThreadPoolStats()
 	.WithGcStats()
+	.WithExceptionStats()
 	.StartCollecting();
 ```
 

src/prometheus-net.DotNetRuntime.Tests/StatsCollectors/IntegrationTests/ExceptionStatsCollectorTests.cs

@@ -1,6 +1,7 @@
 using NUnit.Framework;
 using Prometheus.DotNetRuntime.StatsCollectors;
 using System;
+using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 
@@ -17,36 +18,19 @@ protected override ExceptionStatsCollector CreateStatsCollector()
         [Test]
         public void Will_measure_when_occurring_an_exception()
         {
-            // arrange
-            int divider = 0;
-            string exceptionMessage = string.Empty;
-
             // act
+            var divider = 0;
+            
             try
             {
                 var result = 1 / divider;
             }
-            catch (Exception ex)
+            catch (System.DivideByZeroException divZeroEx)
             {
-                exceptionMessage = ex.GetType().FullName;
             }
 
             // assert
-            Assert.That(() => StatsCollector.ExceptionReasons.Labels(exceptionMessage).Value, Is.EqualTo(1).After(100, 1000));
-        }
-
-        [Test]
-        public void Will_measure_when_not_occurring_an_exception()
-        {
-            // arrange
-            int divider = 1;
-            string exceptionMessage = string.Empty;
-
-            // act
-            var result = 1 / divider;
-
-            // assert
-            Assert.That(() => StatsCollector.ExceptionReasons.Labels(exceptionMessage).Value, Is.EqualTo(0).After(100, 1000));
+            Assert.That(() => StatsCollector.ExceptionCount.Labels("System.DivideByZeroException").Value, Is.EqualTo(1).After(100, 1000));
         }
     }
 }

src/prometheus-net.DotNetRuntime/DotNetRuntimeStatsBuilder.cs

@@ -151,7 +151,7 @@ public Builder WithGcStats(double[] histogramBuckets = null)
             }
 
             /// <summary>
-            /// Includes quantitative and qualitative metrics of exceptions thrown
+            /// Includes a breakdown of exceptions thrown labeled by type.
             /// </summary>
             public Builder WithExceptionStats()
             {

src/prometheus-net.DotNetRuntime/StatsCollectors/ExceptionStatsCollector.cs

@@ -11,9 +11,9 @@ namespace Prometheus.DotNetRuntime.StatsCollectors
     public class ExceptionStatsCollector : IEventSourceStatsCollector
     {
         private const int EventIdExceptionThrown = 80;
-        private const string LabelReason = "exception";
+        private const string LabelType = "type";
 
-        internal Counter ExceptionReasons { get; private set; }
+        internal Counter ExceptionCount { get; private set; }
 
         public Guid EventSourceGuid => DotNetRuntimeEventSource.Id;
 
@@ -22,10 +22,10 @@ public class ExceptionStatsCollector : IEventSourceStatsCollector
 
         public void RegisterMetrics(MetricFactory metrics)
         {
-            ExceptionReasons = metrics.CreateCounter(
-                "dotnet_exception_reasons_total",
-                "Reasons that led to an exception",
-                LabelReason
+            ExceptionCount = metrics.CreateCounter(
+                "dotnet_exceptions_total",
+                "Count of exceptions broken down by type",
+                LabelType
             );
         }
 
@@ -38,7 +38,7 @@ public void ProcessEvent(EventWrittenEventArgs e)
         {
             if (e.EventId == EventIdExceptionThrown)
             {
-                ExceptionReasons.Labels((string)e.Payload[0]).Inc();
+                ExceptionCount.Labels((string)e.Payload[0]).Inc();
             }
         }
     }

src/prometheus-net.DotNetRuntime/prometheus-net.DotNetRuntime.csproj

@@ -5,12 +5,13 @@
         <RootNamespace>Prometheus.DotNetRuntime</RootNamespace>
         <AssemblyName>prometheus-net.DotNetRuntime</AssemblyName>
         <PackageId>prometheus-net.DotNetRuntime</PackageId>
-        <Version>$(PromMajorVersion).3.1</Version>
+        <!-- TODO use git versioning -->
+        <Version>$(PromMajorVersion).4.0</Version>
         <Authors>James Luck</Authors>
         <PackageTags>Prometheus prometheus-net IOnDemandCollector runtime metrics gc jit threadpool contention stats</PackageTags>
         <PackageProjectUrl>https://github.com/djluck/prometheus-net.DotNetRuntime</PackageProjectUrl>
         <Description>
-            Exposes .NET core runtime metrics (GC, JIT, lock contention, thread pool) using the prometheus-net package.
+            Exposes .NET core runtime metrics (GC, JIT, lock contention, thread pool, exceptions) using the prometheus-net package.
         </Description>
         <PackageLicense>https://github.com/djluck/prometheus-net.DotNetRuntime/blob/master/LICENSE.txt</PackageLicense>
         <Configurations>ReleaseV2;DebugV2;DebugV3;ReleaseV3</Configurations>