Add new mechanism to enable creation of DiagnosticContext scopes

samples/ContextAwareServiceSample/ContextAwareServiceSample.csproj

@@ -0,0 +1,17 @@
+<Project Sdk="Microsoft.NET.Sdk.Worker">
+
+    <PropertyGroup>
+        <TargetFramework>netcoreapp3.1</TargetFramework>
+    </PropertyGroup>
+
+    <ItemGroup>
+        <ProjectReference Include="..\..\src\Serilog.Extensions.Hosting\Serilog.Extensions.Hosting.csproj" />
+    </ItemGroup>
+
+    <ItemGroup>
+        <PackageReference Include="Microsoft.Extensions.Hosting" Version="3.1.4" />
+        <PackageReference Include="Serilog.Sinks.Console" Version="3.1.1" />
+        <PackageReference Include="Serilog.Settings.Configuration" Version="3.1.0" />
+        <PackageReference Include="Serilog.Sinks.Seq" Version="5.0.1" />
+    </ItemGroup>
+</Project>

samples/ContextAwareServiceSample/Program.cs

@@ -0,0 +1,45 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Hosting;
+using Serilog;
+
+namespace ContextAwareServiceSample
+{
+    public static class Program
+    {
+        public static int Main(string[] args)
+        {
+            Log.Logger = new LoggerConfiguration()
+                .Enrich.FromLogContext()
+                .WriteTo.Console()
+                .CreateBootstrapLogger();
+
+            try {
+                Log.Information("Getting the motors running...");
+                CreateHostBuilder(args).Build().Run();
+                return 0;
+            }
+            catch (Exception ex) {
+                Log.Fatal(ex, "Host terminated unexpectedly");
+                return 1;
+            }
+            finally {
+                Log.CloseAndFlush();
+            }
+        }
+
+        public static IHostBuilder CreateHostBuilder(string[] args) =>
+            Host.CreateDefaultBuilder(args)
+                .ConfigureServices(services =>
+                    services.AddHostedService<Worker>()
+                        .AddSingleton<WorkExecutor>())
+                .UseSerilog((context, services, loggerConfiguration) => loggerConfiguration
+                    .ReadFrom.Configuration(context.Configuration)
+                    .WriteTo.Seq("http://localhost:5341")
+                    .Enrich.FromLogContext()
+                    .WriteTo.Console());
+    }
+}

samples/ContextAwareServiceSample/Properties/launchSettings.json

@@ -0,0 +1,11 @@
+{
+  "profiles": {
+    "ContextAwareServiceSample": {
+      "commandName": "Project",
+      "dotnetRunMessages": "true",
+      "environmentVariables": {
+        "DOTNET_ENVIRONMENT": "Development"
+      }
+    }
+  }
+}

samples/ContextAwareServiceSample/Worker.cs

@@ -0,0 +1,73 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.Extensions.Hosting;
+using Microsoft.Extensions.Logging;
+using Serilog;
+using ILogger = Serilog.ILogger;
+
+namespace ContextAwareServiceSample
+{
+    public class Worker : BackgroundService
+    {
+        readonly WorkExecutor _executor;
+        readonly IDiagnosticContext _diagnosticContext;
+
+        public Worker(WorkExecutor executor, IDiagnosticContext diagnosticContext)
+        {
+            _executor = executor;
+            _diagnosticContext = diagnosticContext;
+        }
+
+        protected override async Task ExecuteAsync(CancellationToken stoppingToken)
+        {
+            while (!stoppingToken.IsCancellationRequested) {
+                var outerOpId = Guid.NewGuid();
+                using (_diagnosticContext.Begin(
+                    "Worker executed operation {OperationId} at time {Time}",
+                    outerOpId, DateTimeOffset.Now)) {
+                    await _executor.DoWork(outerOpId);
+
+                    var innerOpId = Guid.NewGuid();
+                    using (_diagnosticContext.Begin(
+                        "Worker executed inner operation {OperationId} at time {Time}",
+                        innerOpId,
+                        DateTimeOffset.Now)) {
+                        await _executor.DoWork(innerOpId);
+                    }
+                }
+
+                await Task.Delay(1000, stoppingToken);
+            }
+        }
+    }
+
+    public class WorkExecutor
+    {
+        readonly IDiagnosticContext _diagnosticContext;
+
+        public WorkExecutor(IDiagnosticContext diagnosticContext)
+        {
+            _diagnosticContext = diagnosticContext;
+        }
+
+        public async Task DoWork(Guid operationId)
+        {
+            var R = new Random();
+
+            var operationNames = new[] { "SaveUser", "LoadUser", "AddRole", "RemoveRole", "DeactivateUser" };
+
+            var randomOperation = operationNames[R.Next(0, operationNames.Length - 1)];
+
+            _diagnosticContext.Set("OperationName", randomOperation);
+            _diagnosticContext.Set("ThisOperationId", operationId);
+
+            await Task.Delay(R.Next(100, 1000));
+
+            Log.Information("Completed operation {OperationId}: {OperationName}", operationId,
+                randomOperation);
+        }
+    }
+}

samples/ContextAwareServiceSample/appsettings.Development.json

@@ -0,0 +1,9 @@
+{
+  "Logging": {
+    "LogLevel": {
+      "Default": "Information",
+      "Microsoft": "Warning",
+      "Microsoft.Hosting.Lifetime": "Information"
+    }
+  }
+}

samples/ContextAwareServiceSample/appsettings.json

@@ -0,0 +1,9 @@
+{
+  "Logging": {
+    "LogLevel": {
+      "Default": "Information",
+      "Microsoft": "Warning",
+      "Microsoft.Hosting.Lifetime": "Information"
+    }
+  }
+}

serilog-extensions-hosting.sln

@@ -26,6 +26,8 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "SimpleServiceSample", "samp
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "WebApplicationSample", "samples\WebApplicationSample\WebApplicationSample.csproj", "{1ACDCA67-F404-45AB-9348-98E55E03CB8C}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ContextAwareServiceSample", "samples\ContextAwareServiceSample\ContextAwareServiceSample.csproj", "{41535D34-1DC8-4BC9-A085-208AF948ED00}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -48,6 +50,10 @@ Global
 		{1ACDCA67-F404-45AB-9348-98E55E03CB8C}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{1ACDCA67-F404-45AB-9348-98E55E03CB8C}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{1ACDCA67-F404-45AB-9348-98E55E03CB8C}.Release|Any CPU.Build.0 = Release|Any CPU
+		{41535D34-1DC8-4BC9-A085-208AF948ED00}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{41535D34-1DC8-4BC9-A085-208AF948ED00}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{41535D34-1DC8-4BC9-A085-208AF948ED00}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{41535D34-1DC8-4BC9-A085-208AF948ED00}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -57,6 +63,7 @@ Global
 		{AD51759B-CD58-473F-9620-0B0E56A123A1} = {E30F638E-BBBE-4AD1-93CE-48CC69CFEFE1}
 		{E5A82756-4619-4E6B-8B26-6D83E00E99F0} = {F2407211-6043-439C-8E06-3641634332E7}
 		{1ACDCA67-F404-45AB-9348-98E55E03CB8C} = {F2407211-6043-439C-8E06-3641634332E7}
+		{41535D34-1DC8-4BC9-A085-208AF948ED00} = {F2407211-6043-439C-8E06-3641634332E7}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {811E61C5-3871-4633-AFAE-B35B619C8A10}

src/Serilog.Extensions.Hosting/Extensions/Hosting/DiagnosticContext.cs

@@ -14,6 +14,7 @@
 
 using System;
 using System.Threading;
+using Serilog.Events;
 
 namespace Serilog.Extensions.Hosting
 {
@@ -56,5 +57,16 @@ public void Set(string propertyName, object value, bool destructureObjects = fal
                 collector.AddOrUpdate(property);
             }
         }
+
+        /// <summary>
+        /// 
+        /// </summary>
+        /// <param name="messageTemplate"></param>
+        /// <param name="properties"></param>
+        /// <returns></returns>
+        public DiagnosticContextScope Begin(string messageTemplate, params object[] properties)
+        {
+            return new DiagnosticContextScope(this, LogEventLevel.Information, messageTemplate, properties);
+        }
     }
 }

src/Serilog.Extensions.Hosting/Extensions/Hosting/DiagnosticContextScope.cs

@@ -0,0 +1,57 @@
+using System;
+using System.Linq;
+using Serilog.Events;
+using Serilog.Extensions.Hosting;
+using Serilog.Parsing;
+
+namespace Serilog.Extensions
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    public sealed class DiagnosticContextScope : IDisposable
+    {
+        readonly LogEventLevel _level;
+        readonly string _messageTemplate;
+        readonly object[] _properties;
+        readonly DiagnosticContextCollector _collector;
+
+        static readonly LogEventProperty[] NoProperties = new LogEventProperty[0];
+
+        /// <summary>
+        /// 
+        /// </summary>
+        /// <param name="diagnosticContext"></param>
+        /// <param name="level"></param>
+        /// <param name="messageTemplate"></param>
+        /// <param name="properties"></param>
+        public DiagnosticContextScope(DiagnosticContext diagnosticContext,
+            LogEventLevel level,
+            string messageTemplate,
+            object[] properties)
+        {
+            _level = level;
+            _messageTemplate = messageTemplate;
+            _properties = properties;
+
+            _collector = diagnosticContext.BeginCollection();
+        }
+
+        /// <summary>
+        /// 
+        /// </summary>
+        public void Dispose()
+        {
+            var logger = Log.ForContext<DiagnosticContextScope>();
+
+            if (!_collector.TryComplete(out var collectedProperties))
+                collectedProperties = NoProperties;
+
+            foreach(var collectedProp in collectedProperties) {
+                logger = logger.ForContext(collectedProp.Name, collectedProp.Value);
+            }
+
+            logger.Write(_level, (Exception)null, _messageTemplate, _properties);
+        }
+    }
+}

src/Serilog.Extensions.Hosting/IDiagnosticContext.cs

@@ -12,6 +12,9 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+using Serilog.Events;
+using Serilog.Extensions;
+
 namespace Serilog
 {
     /// <summary>
@@ -27,6 +30,12 @@ public interface IDiagnosticContext
         /// <param name="value">The property value.</param>
         /// <param name="destructureObjects">If true, the value will be serialized as structured
         /// data if possible; if false, the object will be recorded as a scalar or simple array.</param>
-        void Set(string propertyName, object value, bool destructureObjects = false); 
+        void Set(string propertyName, object value, bool destructureObjects = false);
+
+        /// <summary>
+        /// 
+        /// </summary>
+        /// <returns></returns>
+        DiagnosticContextScope Begin(string messageTemplate, params object[] properties);
     }
 }