Merge pull request #183 from serilog/provide-ilogger

Allow an ILogger to be specified in `SerilogRequestLoggingOptions`

Author: nblumhardt

src/Serilog.AspNetCore/AspNetCore/RequestLoggingMiddleware.cs

@@ -24,13 +24,15 @@
 
 namespace Serilog.AspNetCore
 {
+    // ReSharper disable once ClassNeverInstantiated.Global
     class RequestLoggingMiddleware
     {
         readonly RequestDelegate _next;
         readonly DiagnosticContext _diagnosticContext;
         readonly MessageTemplate _messageTemplate;
         readonly Action<IDiagnosticContext, HttpContext> _enrichDiagnosticContext;
         readonly Func<HttpContext, double, Exception, LogEventLevel> _getLevel;
+        readonly ILogger _logger;
         static readonly LogEventProperty[] NoProperties = new LogEventProperty[0];
 
         public RequestLoggingMiddleware(RequestDelegate next, DiagnosticContext diagnosticContext, RequestLoggingOptions options)
@@ -42,6 +44,7 @@ public RequestLoggingMiddleware(RequestDelegate next, DiagnosticContext diagnost
             _getLevel = options.GetLevel;
             _enrichDiagnosticContext = options.EnrichDiagnosticContext;
             _messageTemplate = new MessageTemplateParser().Parse(options.MessageTemplate);
+            _logger = options.Logger?.ForContext<RequestLoggingMiddleware>();
         }
 
         // ReSharper disable once UnusedMember.Global
@@ -73,7 +76,7 @@ public async Task Invoke(HttpContext httpContext)
 
         bool LogCompletion(HttpContext httpContext, DiagnosticContextCollector collector, int statusCode, double elapsedMs, Exception ex)
         {
-            var logger = Log.ForContext<RequestLoggingMiddleware>();
+            var logger = _logger ?? Log.ForContext<RequestLoggingMiddleware>();
             var level = _getLevel(httpContext, elapsedMs, ex);
 
             if (!logger.IsEnabled(level)) return false;

src/Serilog.AspNetCore/AspNetCore/RequestLoggingOptions.cs

@@ -16,6 +16,8 @@
 using Serilog.Events;
 using System;
 
+// ReSharper disable UnusedAutoPropertyAccessor.Global
+
 namespace Serilog.AspNetCore
 {
     /// <summary>
@@ -50,6 +52,13 @@ public class RequestLoggingOptions
         /// </summary>
         public Action<IDiagnosticContext, HttpContext> EnrichDiagnosticContext { get; set; }
 
+
+        /// <summary>
+        /// The logger through which request completion events will be logged. The default is to use the
+        /// static <see cref="Log"/> class.
+        /// </summary>
+        public ILogger Logger { get; set; }
+
         internal RequestLoggingOptions() { }
     }
 }