Add ConfigRefresher for SelfDiagnostics

BASE/Test/Microsoft.ApplicationInsights.Test/Microsoft.ApplicationInsights.Tests/Extensibility/Implementation/Tracing/SelfDiagnostics/SelfDiagnosticsEventListenerTest.cs

@@ -9,11 +9,6 @@
     using Microsoft.VisualStudio.TestTools.UnitTesting;
     using Moq;
 
-    // SelfDiagnosticsEventListener should be moved from SelfDiagnosticsInternals to SelfDiagnostics.
-    // Pending on https://github.com/microsoft/ApplicationInsights-dotnet/pull/2262
-    // Here still using this old namespace to show less changes in git diff view.
-    using Microsoft.ApplicationInsights.Extensibility.Implementation.Tracing.SelfDiagnosticsInternals;
-
     [TestClass]
     class SelfDiagnosticsEventListenerTest
     {

BASE/src/Microsoft.ApplicationInsights/Extensibility/Implementation/Tracing/SelfDiagnostics/SelfDiagnosticsConfigRefresher.cs

@@ -0,0 +1,117 @@
+namespace Microsoft.ApplicationInsights.Extensibility.Implementation.Tracing.SelfDiagnostics
+{
+    using System;
+    using System.Diagnostics;
+    using System.Diagnostics.Tracing;
+    using System.IO;
+    using System.Text;
+    using System.Threading;
+    using System.Threading.Tasks;
+
+    /// <summary>
+    /// SelfDiagnosticsConfigRefresher class checks a location for a configuration file
+    /// and open a MemoryMappedFile of a configured size at the configured file path.
+    /// The class provides a stream object with proper write position if the configuration
+    /// file is present and valid. Otherwise, the stream object would be unavailable,
+    /// nothing will be logged to any file.
+    /// </summary>
+    internal class SelfDiagnosticsConfigRefresher : IDisposable
+    {
+        private const int ConfigurationUpdatePeriodMilliSeconds = 10000;
+
+        private readonly CancellationTokenSource cancellationTokenSource;
+        private readonly Task worker;
+        private readonly SelfDiagnosticsConfigParser configParser;
+        private readonly MemoryMappedFileHandler memoryMappedFileHandler;
+
+        private bool disposedValue;
+
+        // Once the configuration file is valid, an eventListener object will be created.
+        private SelfDiagnosticsEventListener eventListener;
+
+        private EventLevel logEventLevel = (EventLevel)(-1);
+
+        public SelfDiagnosticsConfigRefresher()
+        {
+            this.configParser = new SelfDiagnosticsConfigParser();
+            this.memoryMappedFileHandler = new MemoryMappedFileHandler();
+            this.UpdateMemoryMappedFileFromConfiguration();
+            this.cancellationTokenSource = new CancellationTokenSource();
+            this.worker = Task.Run(() => this.Worker(this.cancellationTokenSource.Token), this.cancellationTokenSource.Token);
+        }
+
+        /// <inheritdoc/>
+        public void Dispose()
+        {
+            this.Dispose(true);
+            GC.SuppressFinalize(this);
+        }
+
+        private async Task Worker(CancellationToken cancellationToken)
+        {
+            await Task.Delay(ConfigurationUpdatePeriodMilliSeconds, cancellationToken).ConfigureAwait(false);
+            while (!cancellationToken.IsCancellationRequested)
+            {
+                this.UpdateMemoryMappedFileFromConfiguration();
+                await Task.Delay(ConfigurationUpdatePeriodMilliSeconds, cancellationToken).ConfigureAwait(false);
+            }
+        }
+
+        private void UpdateMemoryMappedFileFromConfiguration()
+        {
+            if (this.configParser.TryGetConfiguration(out string newLogDirectory, out int fileSizeInKB, out EventLevel newEventLevel))
+            {
+                int newFileSize = fileSizeInKB * 1024;
+                if (!newLogDirectory.Equals(this.memoryMappedFileHandler.LogDirectory, StringComparison.Ordinal) || this.memoryMappedFileHandler.LogFileSize != newFileSize)
+                {
+                    this.memoryMappedFileHandler.CloseLogFile();
+                    this.memoryMappedFileHandler.CreateLogFile(newLogDirectory, newFileSize);
+                }
+
+                if (!newEventLevel.Equals(this.logEventLevel))
+                {
+                    if (this.eventListener != null)
+                    {
+                        this.eventListener.Dispose();
+                    }
+
+                    this.eventListener = new SelfDiagnosticsEventListener(newEventLevel, this.memoryMappedFileHandler);
+                    this.logEventLevel = newEventLevel;
+                }
+            }
+            else
+            {
+                this.memoryMappedFileHandler.CloseLogFile();
+            }
+        }
+
+        private void Dispose(bool disposing)
+        {
+            if (!this.disposedValue)
+            {
+                if (disposing)
+                {
+                    this.cancellationTokenSource.Cancel(false);
+                    try
+                    {
+                        this.worker.Wait();
+                    }
+                    catch (AggregateException)
+                    {
+                    }
+                    finally
+                    {
+                        this.cancellationTokenSource.Dispose();
+                    }
+
+                    // Ensure worker thread properly finishes.
+                    // Or it might have created another MemoryMappedFile in that thread
+                    // after the Dispose() below is called.
+                    this.memoryMappedFileHandler.Dispose();
+                }
+
+                this.disposedValue = true;
+            }
+        }
+    }
+}

BASE/src/Microsoft.ApplicationInsights/Extensibility/Implementation/Tracing/SelfDiagnosticsInternals/SelfDiagnosticsEventListener.cs → BASE/src/Microsoft.ApplicationInsights/Extensibility/Implementation/Tracing/SelfDiagnostics/SelfDiagnosticsEventListener.cs

@@ -1,4 +1,4 @@
-namespace Microsoft.ApplicationInsights.Extensibility.Implementation.Tracing.SelfDiagnosticsInternals
+namespace Microsoft.ApplicationInsights.Extensibility.Implementation.Tracing.SelfDiagnostics
 {
     using System;
     using System.Collections.Generic;
@@ -8,11 +8,6 @@
     using System.Text;
     using System.Threading;
 
-    // SelfDiagnosticsEventListener should be moved from SelfDiagnosticsInternals to SelfDiagnostics.
-    // Pending on https://github.com/microsoft/ApplicationInsights-dotnet/pull/2262
-    // Here still using this old namespace to show less changes in git diff view.
-    using Microsoft.ApplicationInsights.Extensibility.Implementation.Tracing.SelfDiagnostics;
-
     /// <summary>
     /// SelfDiagnosticsEventListener class enables the events from OpenTelemetry event sources
     /// and write the events to a local file in a circular way.

BASE/src/Microsoft.ApplicationInsights/Extensibility/Implementation/Tracing/SelfDiagnosticsInitializer.cs → BASE/src/Microsoft.ApplicationInsights/Extensibility/Implementation/Tracing/SelfDiagnostics/SelfDiagnosticsInitializer.cs

@@ -1,4 +1,4 @@
-namespace Microsoft.ApplicationInsights.Extensibility.Implementation.Tracing
+namespace Microsoft.ApplicationInsights.Extensibility.Implementation.Tracing.SelfDiagnostics
 {
     using System;
 

BASE/src/Microsoft.ApplicationInsights/Extensibility/TelemetryConfiguration.cs

@@ -14,6 +14,7 @@
     using Microsoft.ApplicationInsights.Extensibility.Implementation.Endpoints;
     using Microsoft.ApplicationInsights.Extensibility.Implementation.Sampling;
     using Microsoft.ApplicationInsights.Extensibility.Implementation.Tracing;
+    using Microsoft.ApplicationInsights.Extensibility.Implementation.Tracing.SelfDiagnostics;
     using Microsoft.ApplicationInsights.Metrics;
     using Microsoft.ApplicationInsights.Metrics.Extensibility;