Adding support for global and thread context stacks for log4net

Adding support for global and thread context stacks for log4net.
This is for Azure#287

README.md

@@ -613,18 +613,21 @@ namespace AspNetCoreEventFlow
 This input enables capturing diagnostic data sent to the [Log4net project](https://logging.apache.org/log4net/).
 
 *Configuration example*
-The Log4net input has one configuration, the Log4net Level:
+The Log4net input has one required configuration, the Log4net Level and 2 optional configurations: globalContextName and logicalThreadContextName
 ```json
 {
   "type": "Log4net",
-  "logLevel": "Debug"
+  "logLevel": "Debug",
+  "globalContextName": "MyGlobalContext",
+  "logicalThreadContextName": "MyLogicalThreadContext"
 }
 ```
 | Field | Values/Types | Required | Description |
 | :---- | :-------------- | :------: | :---------- |
 | `type` | "Log4net" | Yes | Specifies the output type. For this output, it must be "Log4net". |
 | `logLevel` | "Debug", "Info", "Warn", "Error", or "Fatal" | Yes | Specifies minimum [Log4net Level](https://logging.apache.org/log4net/log4net-1.2.11/release/sdk/log4net.Core.Level.html) for captured events. For example, if the level is `Warn`, the input will capture events with levels equal to `Warn`, `Error`, or `Fatal`. |
-
+| `globalContextName` | "<User Defined>" | No | Allows clients to supply custom properties on the global context. These will be tagged to every message |
+| `logicalThreadContextName` | "<User Defined>" | No | Allows clients to supply custom properties at the logical thread context. These will be tagged to every message |
 
 *Example: instantiating a Log4net logger that uses EventFlow Log4net input*
 
@@ -649,7 +652,45 @@ namespace ConsoleApp2
     }
 }
 ```
+*Example: instantiating a Log4net logger that uses EventFlow Log4net input with NDC thread and global contexts*
+
+```csharp
+using System;
+using Microsoft.Diagnostics.EventFlow;
+using log4net;
+
+namespace ConsoleApp2
+{
+    class Program
+    {
+        static void Main(string[] args)
+        {
+            using (DiagnosticPipeline pipeline = DiagnosticPipelineFactory.CreatePipeline(".\\eventFlowConfig.json"))
+            {
+                #region log4net input with stacks and global context
+                var logger = LogManager.GetLogger("EventFlowRepo", "MY_LOGGER_NAME");
+                GlobalContext.Properties["GlobalContext"] = "My Global Context";
+
+                using (ThreadContext.Stacks["NDC"].Push("Thread Context-1"))
+                {
+                    using (ThreadContext.Stacks["NDC"].Push("Thread Context-1-1"))
+                    {
+                        using (LogicalThreadContext.Stacks["LogicalThreadContext"].Push("Logical Thread Context-1-1-1"))
+                        {
+                            logger.Debug("Hey! Listen!", new Exception("uhoh"));
+                        }
+                        logger.Info("From Thread Context 1-1");
+                    }
+                    logger.Info("From Thread Context 1");
+                }
+                #endregion
 
+                Console.ReadLine();               
+            }
+        }
+    }
+}
+```
 #### NLog
 
 *Nuget package:* [**Microsoft.Diagnostics.EventFlow.Inputs.NLog**](https://www.nuget.org/packages/Microsoft.Diagnostics.EventFlow.Inputs.NLog/)

src/Microsoft.Diagnostics.EventFlow.Consumers.ConsoleApp/Microsoft.Diagnostics.EventFlow.Consumers.ConsoleApp.csproj

@@ -11,14 +11,22 @@
   <ItemGroup>
     <ProjectReference Include="..\Microsoft.Diagnostics.EventFlow.Core\Microsoft.Diagnostics.EventFlow.Core.csproj" />
     <ProjectReference Include="..\Microsoft.Diagnostics.EventFlow.Inputs.EventSource\Microsoft.Diagnostics.EventFlow.Inputs.EventSource.csproj" />
+    <ProjectReference Include="..\Microsoft.Diagnostics.EventFlow.Inputs.Log4net\Microsoft.Diagnostics.EventFlow.Inputs.Log4net.csproj" />
     <ProjectReference Include="..\Microsoft.Diagnostics.EventFlow.Inputs.PerformanceCounter\Microsoft.Diagnostics.EventFlow.Inputs.PerformanceCounter.csproj" />
     <ProjectReference Include="..\Microsoft.Diagnostics.EventFlow.Inputs.Trace\Microsoft.Diagnostics.EventFlow.Inputs.Trace.csproj" />
     <ProjectReference Include="..\Microsoft.Diagnostics.EventFlow.Outputs.StdOutput\Microsoft.Diagnostics.EventFlow.Outputs.StdOutput.csproj" />
   </ItemGroup>
 
   <ItemGroup>
+    <PackageReference Include="log4net" Version="2.0.8" />
     <PackageReference Include="System.Net.Http" Version="4.3.1" />
     <PackageReference Include="Microsoft.Extensions.Configuration.Abstractions" Version="1.1.1" />
   </ItemGroup>
 
+  <ItemGroup>
+    <None Update="eventFlowConfig.json">
+      <CopyToOutputDirectory>Always</CopyToOutputDirectory>
+    </None>
+  </ItemGroup>
+
 </Project>

src/Microsoft.Diagnostics.EventFlow.Consumers.ConsoleApp/Program.cs

@@ -2,6 +2,7 @@
 //  Copyright (c) Microsoft Corporation.  All rights reserved.
 //  Licensed under the MIT License (MIT). See License.txt in the repo root for license information.
 // ------------------------------------------------------------
+using log4net;
 using System;
 using System.Diagnostics;
 using System.Net.Http;
@@ -12,8 +13,28 @@ class Program
     {
         static void Main(string[] args)
         {
-            using (DiagnosticPipeline pipeline = DiagnosticPipelineFactory.CreatePipeline("eventFlowConfig.json"))
+            using (DiagnosticPipeline pipeline = DiagnosticPipelineFactory.CreatePipeline(".\\eventFlowConfig.json"))
             {
+                #region log4net input with stacks and global context
+                var logger = LogManager.GetLogger("EventFlowRepo", "MY_LOGGER_NAME");
+                GlobalContext.Properties["GlobalContext"] = "My Global Context";
+
+                using (ThreadContext.Stacks["NDC"].Push("Thread Context-1"))
+                {
+                    using (ThreadContext.Stacks["NDC"].Push("Thread Context-1-1"))
+                    {
+                        using (LogicalThreadContext.Stacks["LogicalThreadContext"].Push("Logical Thread Context-1-1-1"))
+                        {
+                            logger.Debug("Hey! Listen!", new Exception("uhoh"));
+                        }
+                        logger.Info("From Thread Context 1-1");
+                    }
+                    logger.Info("From Thread Context 1");
+                }
+                #endregion
+
+                Console.ReadLine();
+
                 // Build up the pipeline
                 Console.WriteLine("Pipeline is created.");
 

src/Microsoft.Diagnostics.EventFlow.Consumers.ConsoleApp/eventFlowConfig.json

@@ -19,6 +19,12 @@
         //}
       ]
     },
+    {
+      "type": "Log4net",
+      "logLevel": "Debug",
+      "globalContextName": "GlobalContext",
+      "logicalThreadContextName": "LogicalThreadContext"
+    },
     {
       "type": "PerformanceCounter",
       "counters": [

src/Microsoft.Diagnostics.EventFlow.Inputs.Log4net/Configuration/Log4netConfiguration.cs

@@ -14,5 +14,9 @@ public class Log4netConfiguration : ItemConfiguration
         public string LogLevel { get; set; }
 
         public Level Log4netLevel { get; set; }
+
+        public string GlobalContextName { get; set; }
+
+        public string LogicalThreadContextName { get; set; }
     }
 }

src/Microsoft.Diagnostics.EventFlow.Inputs.Log4net/Log4netInput.cs

@@ -34,7 +34,7 @@ public class Log4netInput : AppenderSkeleton, IObservable<EventData>, IDisposabl
         private EventFlowSubject<EventData> subject;
         private Log4netConfiguration _log4NetInputConfiguration;
         private Hierarchy eventFlowRepo;
-
+       
         public Log4netInput(IConfiguration configuration, IHealthReporter healthReporter)
         {
             Requires.NotNull(healthReporter, nameof(healthReporter));
@@ -84,7 +84,7 @@ private void Initialize(Log4netConfiguration myLog4NetConfig, IHealthReporter my
                 eventFlowRepo = (Hierarchy) LogManager.GetRepository("EventFlowRepo");
             }
         }
-
+        
         protected override void Append(LoggingEvent loggingEvent)
         {
             if (loggingEvent == null || !IsEnabledFor(loggingEvent.Level))
@@ -106,14 +106,14 @@ private EventData ToEventData(LoggingEvent loggingEvent)
                 Timestamp = loggingEvent.TimeStamp,
                 Level = ToLogLevel[loggingEvent.Level],
                 Keywords = 0,
-                Payload = { { "Message", loggingEvent.MessageObject } }
+                Payload = { { "Message", $"{AttachGlobalContextProps()} {AttachThreadContextProps()} {AttachLogicalThreadContextProps()} {loggingEvent.MessageObject}" } }
             };
-
+         
             if (loggingEvent.ExceptionObject != null)
             {
                 eventData.Payload.Add("Exception", loggingEvent.ExceptionObject);
             }
-
+            
             foreach (var key in loggingEvent.Properties.GetKeys())
             {
                 try
@@ -129,6 +129,27 @@ private EventData ToEventData(LoggingEvent loggingEvent)
             return eventData;
         }
 
+        private string AttachGlobalContextProps()
+        {            
+            return $"[{log4net.GlobalContext.Properties[this._log4NetInputConfiguration.GlobalContextName ?? "GlobalContext"]?.ToString()}]";
+        }
+
+        private string AttachThreadContextProps()
+        {
+            string result = null;
+            var keys = log4net.ThreadContext.Properties.GetKeys();
+            foreach (var item in keys)
+            {
+                result += $"[{log4net.ThreadContext.Properties[item]}]";
+            }
+            return result;
+        }
+
+        private string AttachLogicalThreadContextProps()
+        {                 
+            return $"[{log4net.LogicalThreadContext.Properties[this._log4NetInputConfiguration.LogicalThreadContextName ?? "LogicalThreadContext"]?.ToString()}]";
+        }
+
         /// <inheritdoc/>
         public virtual void Dispose()
         {