Enable the self diagnostics and fix a NullReferenceException bug

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

@@ -1,11 +1,9 @@
 namespace Microsoft.ApplicationInsights.Extensibility.Implementation.Tracing.SelfDiagnostics
 {
     using System;
-    using System.Collections.Generic;
     using System.Diagnostics.Tracing;
-    using System.Linq;
+    using System.Globalization;
     using System.Text;
-    using System.Threading.Tasks;
     using Microsoft.VisualStudio.TestTools.UnitTesting;
     using Moq;
 
@@ -55,9 +53,9 @@ public void SelfDiagnosticsEventListener_DateTimeGetBytes()
             // Check DateTimeKind of Utc, Local, and Unspecified
             DateTime[] datetimes = new DateTime[]
             {
-                DateTime.SpecifyKind(DateTime.Parse("1996-12-01T14:02:31.1234567-08:00"), DateTimeKind.Utc),
-                DateTime.SpecifyKind(DateTime.Parse("1996-12-01T14:02:31.1234567-08:00"), DateTimeKind.Local),
-                DateTime.SpecifyKind(DateTime.Parse("1996-12-01T14:02:31.1234567-08:00"), DateTimeKind.Unspecified),
+                DateTime.SpecifyKind(DateTime.Parse("1996-12-01T14:02:31.1234567-08:00", CultureInfo.InvariantCulture), DateTimeKind.Utc),
+                DateTime.SpecifyKind(DateTime.Parse("1996-12-01T14:02:31.1234567-08:00", CultureInfo.InvariantCulture), DateTimeKind.Local),
+                DateTime.SpecifyKind(DateTime.Parse("1996-12-01T14:02:31.1234567-08:00", CultureInfo.InvariantCulture), DateTimeKind.Unspecified),
                 DateTime.UtcNow,
                 DateTime.Now,
             };
@@ -76,14 +74,23 @@ public void SelfDiagnosticsEventListener_DateTimeGetBytes()
             string[] results = new string[datetimes.Length];
             for (int i = 0; i < datetimes.Length; i++)
             {
-                int len = listener.DateTimeGetBytes(datetimes[i], buffer, pos);
+                int len = SelfDiagnosticsEventListener.DateTimeGetBytes(datetimes[i], buffer, pos);
                 results[i] = Encoding.Default.GetString(buffer, pos, len);
                 pos += len;
             }
 
             CollectionAssert.AreEqual(expected, results);
         }
 
+        [TestMethod]
+        public void SelfDiagnosticsEventListener_EncodeInBuffer_Null()
+        {
+            byte[] buffer = new byte[20];
+            int startPos = 0;
+            int endPos = SelfDiagnosticsEventListener.EncodeInBuffer(null, false, buffer, startPos);
+            Assert.AreEqual(startPos, endPos);
+        }
+
         [TestMethod]
         public void SelfDiagnosticsEventListener_EncodeInBuffer_Empty()
         {

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

@@ -105,6 +105,10 @@ private void Dispose(bool disposing)
                     // Or it might have created another MemoryMappedFile in that thread
                     // after the Dispose() below is called.
                     this.memoryMappedFileHandler.Dispose();
+                    if (this.eventListener != null)
+                    {
+                        this.eventListener.Dispose();
+                    }
                 }
 
                 this.disposedValue = true;

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

@@ -53,6 +53,7 @@ public SelfDiagnosticsEventListener(EventLevel logLevel, MemoryMappedFileHandler
         public override void Dispose()
         {
             this.Dispose(true);
+            base.Dispose();
             GC.SuppressFinalize(this);
         }
 
@@ -71,6 +72,11 @@ public override void Dispose()
         /// <returns>The position of the buffer after the last byte of the resulting sequence.</returns>
         internal static int EncodeInBuffer(string str, bool isParameter, byte[] buffer, int position)
         {
+            if (string.IsNullOrEmpty(str))
+            {
+                return position;
+            }
+
             int charCount = str.Length;
             int ellipses = isParameter ? "{...}\n".Length : "...\n".Length;
 
@@ -110,47 +116,6 @@ internal static int EncodeInBuffer(string str, bool isParameter, byte[] buffer,
             return position;
         }
 
-        internal void WriteEvent(string eventMessage, ReadOnlyCollection<object> payload)
-        {
-            try
-            {
-                var buffer = this.writeBuffer.Value;
-                if (buffer == null)
-                {
-                    buffer = new byte[BUFFERSIZE];
-                    this.writeBuffer.Value = buffer;
-                }
-
-                var pos = this.DateTimeGetBytes(DateTime.UtcNow, buffer, 0);
-                buffer[pos++] = (byte)':';
-                pos = EncodeInBuffer(eventMessage, false, buffer, pos);
-                if (payload != null)
-                {
-                    // Not using foreach because it can cause allocations
-                    for (int i = 0; i < payload.Count; ++i)
-                    {
-                        object obj = payload[i];
-                        if (obj != null)
-                        {
-                            pos = EncodeInBuffer(obj.ToString(), true, buffer, pos);
-                        }
-                        else
-                        {
-                            pos = EncodeInBuffer("null", true, buffer, pos);
-                        }
-                    }
-                }
-
-                buffer[pos++] = (byte)'\n';
-                this.fileHandler.Write(buffer, pos - 0);
-            }
-            catch (Exception)
-            {
-                // Fail to allocate memory for buffer
-                // In this case, silently fail.
-            }
-        }
-
         /// <summary>
         /// Write the <c>datetime</c> formatted string into <c>bytes</c> byte-array starting at <c>byteIndex</c> position.
         /// <para>
@@ -173,7 +138,7 @@ internal void WriteEvent(string eventMessage, ReadOnlyCollection<object> payload
         /// <param name="bytes">Array of bytes to write.</param>
         /// <param name="byteIndex">Starting index into bytes array.</param>
         /// <returns>The number of bytes written.</returns>
-        internal int DateTimeGetBytes(DateTime datetime, byte[] bytes, int byteIndex)
+        internal static int DateTimeGetBytes(DateTime datetime, byte[] bytes, int byteIndex)
         {
             int num;
             int pos = byteIndex;
@@ -256,6 +221,47 @@ internal int DateTimeGetBytes(DateTime datetime, byte[] bytes, int byteIndex)
             return pos - byteIndex;
         }
 
+        internal void WriteEvent(string eventMessage, ReadOnlyCollection<object> payload)
+        {
+            try
+            {
+                var buffer = this.writeBuffer.Value;
+                if (buffer == null)
+                {
+                    buffer = new byte[BUFFERSIZE];
+                    this.writeBuffer.Value = buffer;
+                }
+
+                var pos = DateTimeGetBytes(DateTime.UtcNow, buffer, 0);
+                buffer[pos++] = (byte)':';
+                pos = EncodeInBuffer(eventMessage, false, buffer, pos);
+                if (payload != null)
+                {
+                    // Not using foreach because it can cause allocations
+                    for (int i = 0; i < payload.Count; ++i)
+                    {
+                        object obj = payload[i];
+                        if (obj != null)
+                        {
+                            pos = EncodeInBuffer(obj.ToString(), true, buffer, pos);
+                        }
+                        else
+                        {
+                            pos = EncodeInBuffer("null", true, buffer, pos);
+                        }
+                    }
+                }
+
+                buffer[pos++] = (byte)'\n';
+                this.fileHandler.Write(buffer, pos - 0);
+            }
+            catch (Exception)
+            {
+                // Fail to allocate memory for buffer
+                // In this case, silently fail.
+            }
+        }
+
         protected override void OnEventSourceCreated(EventSource eventSource)
         {
             if (eventSource.Name.StartsWith(EventSourceNamePrefix, StringComparison.Ordinal))
@@ -310,9 +316,6 @@ protected virtual void Dispose(bool disposing)
             }
 
             this.disposedValue = true;
-
-            // Should call base.Dispose(disposing) here, but EventListener doesn't have Dispose(bool).
-            base.Dispose();
         }
     }
 }

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

@@ -15,7 +15,7 @@ internal class SelfDiagnosticsInitializer : IDisposable
 
         // Long-living object that holds a refresher which checks whether the configuration file was updated
         // every 10 seconds.
-        // private readonly SelfDiagnosticsConfigRefresher configRefresher;
+        private readonly SelfDiagnosticsConfigRefresher configRefresher;
 
         static SelfDiagnosticsInitializer()
         {
@@ -27,7 +27,7 @@ static SelfDiagnosticsInitializer()
 
         private SelfDiagnosticsInitializer()
         {
-            // this.configRefresher = new SelfDiagnosticsConfigRefresher();
+            this.configRefresher = new SelfDiagnosticsConfigRefresher();
         }
 
         /// <summary>
@@ -54,7 +54,7 @@ protected virtual void Dispose(bool disposing)
         {
             if (disposing)
             {
-                // this.configRefresher.Dispose();
+                this.configRefresher.Dispose();
             }
         }
     }

CHANGELOG.md

@@ -1,7 +1,7 @@
 # Changelog
 
 ## VNext
-
+- [Enable the self diagnostics and fix a NullReferenceException bug](https://github.com/microsoft/ApplicationInsights-dotnet/pull/2302)
 
 ## Version 2.18.0-beta2
 - Reduce technical debt: Use pattern matching