Merge pull request #146 from tomkerkhove/request-log-properties

Add RequestHost & RequestScheme to log properties

Author: nblumhardt

README.md

@@ -82,7 +82,7 @@ That's it! With the level bumped up a little you will see log output resembling:
 
 A more complete example, showing `appsettings.json` configuration, can be found in [the sample project here](https://github.com/serilog/serilog-aspnetcore/tree/dev/samples/EarlyInitializationSample).
 
-### Request logging <sup>`3.0.0-*`</sup>
+### Request logging <sup>`3.0.0`</sup>
 
 The package includes middleware for smarter HTTP request logging. The default request logging implemented by ASP.NET Core is noisy, with multiple events emitted per request. The included middleware condenses these into a single event that carries method, path, status code, and timing information.
 
@@ -159,6 +159,33 @@ During request processing, additional properties can be attached to the completi
 
 This pattern has the advantage of reducing the number of log events that need to be constructed, transmitted, and stored per HTTP request. Having many properties on the same event can also make correlation of request details and other data easier.
 
+The following request information will be added as properties by default:
+
+* `RequestMethod`
+* `RequestPath`
+* `StatusCode`
+* `Elapsed`
+
+You can modify the message template used for request completion events, add additional properties, or change the event level, using the `options` callback on `UseSerilogRequestLogging()`:
+
+```csharp
+app.UseSerilogRequestLogging(options =>
+{
+    // Customize the message template
+    options.MessageTemplate = "Handled {RequestPath}";
+    
+    // Emit debug-level events instead of the defaults
+    options.GetLevel = (httpContext, elapsed, ex) => LogEventLevel.Debug;
+    
+    // Attach additional properties to the request completion event
+    options.EnrichDiagnosticContext = (diagnosticContext, httpContext) =>
+    {
+        diagnosticContext.Set("RequestHost", httpContext.Request.Host.Value);
+        diagnosticContext.Set("RequestScheme", httpContext.Request.Scheme);
+    };
+});
+```
+
 ### Inline initialization
 
 You can alternatively configure Serilog inline, in `BuildWebHost()`, using a delegate as shown below:

samples/EarlyInitializationSample/Startup.cs

@@ -31,7 +31,7 @@ public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
             // To use the default framework request logging instead, remove this line and set the "Microsoft"
             // level in appsettings.json to "Information".
             app.UseSerilogRequestLogging();
-
+            
             app.UseRouting();
 
             app.UseEndpoints(endpoints =>

src/Serilog.AspNetCore/AspNetCore/RequestLoggingMiddleware.cs

@@ -29,6 +29,7 @@ class RequestLoggingMiddleware
         readonly RequestDelegate _next;
         readonly DiagnosticContext _diagnosticContext;
         readonly MessageTemplate _messageTemplate;
+        readonly Action<IDiagnosticContext, HttpContext> _enrichDiagnosticContext;
         readonly Func<HttpContext, double, Exception, LogEventLevel> _getLevel;
         static readonly LogEventProperty[] NoProperties = new LogEventProperty[0];
 
@@ -39,6 +40,7 @@ public RequestLoggingMiddleware(RequestDelegate next, DiagnosticContext diagnost
             _diagnosticContext = diagnosticContext ?? throw new ArgumentNullException(nameof(diagnosticContext));
 
             _getLevel = options.GetLevel;
+            _enrichDiagnosticContext = options.EnrichDiagnosticContext;
             _messageTemplate = new MessageTemplateParser().Parse(options.MessageTemplate);
         }
 
@@ -79,6 +81,9 @@ bool LogCompletion(HttpContext httpContext, DiagnosticContextCollector collector
             if (!collector.TryComplete(out var collectedProperties))
                 collectedProperties = NoProperties;
 
+            // Enrich diagnostic context
+            _enrichDiagnosticContext?.Invoke(_diagnosticContext, httpContext);
+
             // Last-in (correctly) wins...
             var properties = collectedProperties.Concat(new[]
             {

src/Serilog.AspNetCore/AspNetCore/RequestLoggingOptions.cs

@@ -35,16 +35,21 @@ public class RequestLoggingOptions
         public string MessageTemplate { get; set; }
 
         /// <summary>
-        /// Gets or sets the function returning the <see cref="LogEventLevel"/> based on the <see cref="HttpContext"/>, the number of
+        /// A function returning the <see cref="LogEventLevel"/> based on the <see cref="HttpContext"/>, the number of
         /// elapsed milliseconds required for handling the request, and an <see cref="Exception" /> if one was thrown.
         /// The default behavior returns <see cref="LogEventLevel.Error"/> when the response status code is greater than 499 or if the
         /// <see cref="Exception"/> is not null.
         /// </summary>
         /// <value>
-        /// The function returning the <see cref="LogEventLevel"/>.
+        /// A function returning the <see cref="LogEventLevel"/>.
         /// </value>
         public Func<HttpContext, double, Exception, LogEventLevel> GetLevel { get; set; }
 
+        /// <summary>
+        /// A callback that can be used to set additional properties on the request completion event.
+        /// </summary>
+        public Action<IDiagnosticContext, HttpContext> EnrichDiagnosticContext { get; set; }
+
         internal RequestLoggingOptions() { }
     }
-}
+}