[Proof of Concept] Azure Monitor - Refactoring the EventSource

sdk/monitor/OpenTelemetry.Exporter.AzureMonitor/src/AzureMonitorTraceExporter.cs

@@ -46,7 +46,7 @@ public override ExportResult Export(in Batch<Activity> batch)
             }
             catch (Exception ex)
             {
-                AzureMonitorTraceExporterEventSource.Log.FailedExport(ex);
+                AzureMonitorTraceExporterEventSource.Log.Write($"FailedToExport{EventLevelSuffix.Error}", ex.LogAsyncException());
                 return ExportResult.Failure;
             }
         }

sdk/monitor/OpenTelemetry.Exporter.AzureMonitor/src/AzureMonitorTraceExporterEventSource.cs

@@ -2,6 +2,7 @@
 // Licensed under the MIT License.
 
 using System;
+using System.Collections.Generic;
 using System.Diagnostics.Tracing;
 
 namespace OpenTelemetry.Exporter.AzureMonitor
@@ -11,41 +12,64 @@ internal sealed class AzureMonitorTraceExporterEventSource : EventSource
     {
         private const string EventSourceName = "OpenTelemetry-TraceExporter-AzureMonitor";
         public static AzureMonitorTraceExporterEventSource Log = new AzureMonitorTraceExporterEventSource();
-
-        [NonEvent]
-        public void FailedExport(Exception ex)
+        public readonly IReadOnlyDictionary<string, EventLevel> EventLevelMap = new Dictionary<string, EventLevel>
         {
-            if (this.IsEnabled(EventLevel.Error, EventKeywords.All))
-            {
-                this.FailedExport(ex.ToInvariantString());
-            }
-        }
+            [EventLevelSuffix.Critical] = EventLevel.Critical,
+            [EventLevelSuffix.Error] = EventLevel.Error,
+            [EventLevelSuffix.Warning] = EventLevel.Warning,
+            [EventLevelSuffix.Informational] = EventLevel.Informational,
+            [EventLevelSuffix.Verbose] = EventLevel.Verbose
+        };
 
         [NonEvent]
-        public void SdkVersionCreateFailed(Exception ex)
+        public void Write(string name, object value)
         {
-            if (this.IsEnabled(EventLevel.Warning, EventKeywords.All))
-            {
-                this.WarnSdkVersionCreateException(ex.ToInvariantString());
-            }
-        }
+            var lastIndex = name.LastIndexOf('.');
+            var eventLevel = EventLevelMap[name.Substring(lastIndex)];
 
-        [NonEvent]
-        public void ConnectionStringError(Exception ex)
-        {
-            if (this.IsEnabled(EventLevel.Error, EventKeywords.All))
+            if (this.IsEnabled(eventLevel, EventKeywords.All))
             {
-                this.ConnectionStringError(ex.ToInvariantString());
+                var message = $"{name.Trim(lastIndex)} - {GetMessage(value)}";
+
+                switch (eventLevel)
+                {
+                    case EventLevel.Critical:
+                        WriteCritical(message);
+                        break;
+                    case EventLevel.Error:
+                        WriteError(message);
+                        break;
+                    case EventLevel.Informational:
+                        WriteInformational(message);
+                        break;
+                    case EventLevel.Verbose:
+                        WriteVerbose(message);
+                        break;
+                    case EventLevel.Warning:
+                        WriteWarning(message);
+                        break;
+                }
             }
         }
 
-        [Event(1, Message = "Failed to export activities: '{0}'", Level = EventLevel.Error)]
-        public void FailedExport(string exception) => this.WriteEvent(1, exception);
+        [Event(1, Message = "{0}", Level = EventLevel.Critical)]
+        public void WriteCritical(string message) => this.WriteEvent(1, message);
+
+        [Event(2, Message = "{0}", Level = EventLevel.Error)]
+        public void WriteError(string message) => this.WriteEvent(2, message);
 
-        [Event(2, Message = "Error creating SdkVersion : '{0}'", Level = EventLevel.Warning)]
-        public void WarnSdkVersionCreateException(string message) => this.WriteEvent(2, message);
+        [Event(3, Message = "{0}", Level = EventLevel.Warning)]
+        public void WriteWarning(string message) => this.WriteEvent(3, message);
 
-        [Event(3, Message = "Connection String Error: '{0}'", Level = EventLevel.Error)]
-        public void ConnectionStringError(string message) => this.WriteEvent(3, message);
+        [Event(4, Message = "{0}", Level = EventLevel.Informational)]
+        public void WriteInformational(string message) => this.WriteEvent(4, message);
+
+        [Event(5, Message = "{0}", Level = EventLevel.Verbose)]
+        public void WriteVerbose(string message) => this.WriteEvent(5, message);
+
+        private static string GetMessage(object value)
+        {
+            return value is Exception exception ? exception.ToInvariantString() : value.ToString();
+        }
     }
 }

sdk/monitor/OpenTelemetry.Exporter.AzureMonitor/src/AzureMonitorTransmitter.cs

@@ -55,8 +55,8 @@ public async ValueTask<int> TrackAsync(IEnumerable<TelemetryItem> telemetryItems
                 {
                     // TODO: Network issue. Send Telemetry Items To Storage
                 }
-                // TODO: Log the exception to new event source. If we get a common logger we could just log exception to it.
-                AzureMonitorTraceExporterEventSource.Log.FailedExport(ex);
+
+                AzureMonitorTraceExporterEventSource.Log.Write($"FailedToSend{EventLevelSuffix.Error}", ex.LogAsyncException());
             }
 
             return itemsAccepted;

sdk/monitor/OpenTelemetry.Exporter.AzureMonitor/src/ConnectionString/ConnectionStringParser.cs

@@ -37,7 +37,7 @@ public static void GetValues(string connectionString, out string instrumentation
             }
             catch (Exception ex)
             {
-                AzureMonitorTraceExporterEventSource.Log.ConnectionStringError(ex);
+                AzureMonitorTraceExporterEventSource.Log.Write($"ConnectionStringError{EventLevelSuffix.Error}", ex);
                 throw new InvalidOperationException("Connection String Error: " + ex.Message, ex);
             }
         }

sdk/monitor/OpenTelemetry.Exporter.AzureMonitor/src/EventLevelSuffix.cs

@@ -0,0 +1,14 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+namespace OpenTelemetry.Exporter.AzureMonitor
+{
+    internal class EventLevelSuffix
+    {
+        public const string Critical = ".Critical";
+        public const string Error = ".Error";
+        public const string Warning = ".Warning";
+        public const string Informational = ".Informational";
+        public const string Verbose = ".Verbose";
+    }
+}

sdk/monitor/OpenTelemetry.Exporter.AzureMonitor/src/ExceptionExtensions.cs

@@ -23,5 +23,10 @@ internal static string ToInvariantString(this Exception exception)
                 Thread.CurrentThread.CurrentUICulture = originalUICulture;
             }
         }
+
+        internal static Exception LogAsyncException(this Exception exception)
+        {
+            return exception is AggregateException aggregateException ? aggregateException.InnerException : exception;
+        }
     }
 }

sdk/monitor/OpenTelemetry.Exporter.AzureMonitor/src/SdkVersionUtils.cs

@@ -24,7 +24,7 @@ private static string GetSdkVersion()
             }
             catch (Exception ex)
             {
-                AzureMonitorTraceExporterEventSource.Log.SdkVersionCreateFailed(ex);
+                AzureMonitorTraceExporterEventSource.Log.Write($"SdkVersionCreateFailed{EventLevelSuffix.Warning}", ex);
                 return null;
             }
         }

sdk/monitor/OpenTelemetry.Exporter.AzureMonitor/src/StringExtensions.cs

@@ -0,0 +1,15 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+using System;
+
+namespace OpenTelemetry.Exporter.AzureMonitor
+{
+    internal static class StringExtensions
+    {
+        public static string Trim(this string message, int lastIndex)
+        {
+            return message.Substring(0, lastIndex);
+        }
+    }
+}