[WIP] ILogger integration

src/StackExchange.Exceptional.AspNetCore/ExceptionalBuilderExtensions.cs

@@ -1,4 +1,6 @@
-using StackExchange.Exceptional;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Logging;
+using StackExchange.Exceptional;
 using System;
 
 namespace Microsoft.AspNetCore.Builder
@@ -16,7 +18,11 @@ public static class ExceptionalBuilderExtensions
         public static IApplicationBuilder UseExceptional(this IApplicationBuilder builder)
         {
             _ = builder ?? throw new ArgumentNullException(nameof(builder));
+
+            var loggerFactory = builder.ApplicationServices.GetRequiredService<ILoggerFactory>();
+            loggerFactory.AddProvider(builder.ApplicationServices.GetRequiredService<ExceptionalLoggerProvider>());
+
             return builder.UseMiddleware<ExceptionalMiddleware>();
         }
     }
-}
+}

src/StackExchange.Exceptional.AspNetCore/ExceptionalLogger.cs

@@ -0,0 +1,62 @@
+using System;
+using System.Collections.Generic;
+using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Options;
+
+namespace StackExchange.Exceptional
+{
+    class ExceptionalLogger : ILogger
+    {
+        private readonly string _category;
+        private readonly IHttpContextAccessor _httpContextAccessor;
+        private readonly IOptions<ExceptionalSettings> _settings;
+        private readonly bool _ignored;
+        private static readonly HashSet<string> _ignoredCategories = new HashSet<string>
+        {
+            typeof(ExceptionalMiddleware).FullName, // exceptional middleware calls some ILogger stuff itself, ignore those calls)
+        };
+
+        public ExceptionalLogger(string category, IOptions<ExceptionalSettings> settings, IHttpContextAccessor httpContextAccessor = null)
+        {
+            _category = category;
+            _settings = settings;
+            _httpContextAccessor = httpContextAccessor;
+            _ignored = _ignoredCategories.Contains(category);
+        }
+
+        public IDisposable BeginScope<TState>(TState state)
+        {
+            return null;
+        }
+
+        public bool IsEnabled(LogLevel logLevel)
+        {
+            return !_ignored;
+            // TODO compare against settings and add support for per-category log levels, or we can just leave it up to LogFilters to decide later
+        }
+
+        public void Log<TState>(LogLevel logLevel, EventId eventId, TState state, Exception exception, Func<TState, Exception, string> formatter)
+        {
+            if (_ignored) return;
+            if (exception == null) return;
+
+            var customData = new Dictionary<string, string>
+            {
+                ["AspNetCore.LogLevel"] = logLevel + "",
+                ["AspNetCore.EventId.Id"] = eventId.Id + "",
+                ["AspNetCore.EventId.Name"] = eventId.Name,
+                ["AspNetCore.Message"] = formatter(state, exception),
+            };
+
+            if (_httpContextAccessor?.HttpContext is HttpContext context)
+            {
+                exception.Log(context, _category, customData: customData);
+            }
+            else
+            {
+                exception.LogNoContext(_category, customData: customData);
+            }
+        }
+    }
+}

src/StackExchange.Exceptional.AspNetCore/ExceptionalLoggerProvider.cs

@@ -0,0 +1,27 @@
+
+using System;
+using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Options;
+
+namespace StackExchange.Exceptional
+{
+    class ExceptionalLoggerProvider : ILoggerProvider
+    {
+        private readonly IOptions<ExceptionalSettings> _settings;
+        private readonly IHttpContextAccessor _httpContextAccessor;
+
+        public ExceptionalLoggerProvider(IOptions<ExceptionalSettings> settings, IHttpContextAccessor httpContextAccessor = null)
+        {
+            _settings = settings;
+            _httpContextAccessor = httpContextAccessor;
+        }
+
+        ILogger ILoggerProvider.CreateLogger(string categoryName)
+            => new ExceptionalLogger(categoryName, _settings, _httpContextAccessor);
+
+        void IDisposable.Dispose()
+        {
+        }
+    }
+}

src/StackExchange.Exceptional.AspNetCore/ExceptionalServiceExtensions.cs

@@ -1,6 +1,8 @@
 using Microsoft.Extensions.Configuration;
 using StackExchange.Exceptional;
 using System;
+using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.DependencyInjection.Extensions;
 
 namespace Microsoft.Extensions.DependencyInjection
 {
@@ -36,6 +38,10 @@ public static IServiceCollection AddExceptional(this IServiceCollection services
             // When done configuring, set the background settings object for non-context logging.
             services.Configure<ExceptionalSettings>(Exceptional.Configure);
 
+            // setup for ILogger & co
+            services.TryAddSingleton<IHttpContextAccessor, HttpContextAccessor>();
+            services.AddSingleton<ExceptionalLoggerProvider>();
+
             return services;
         }
     }

src/StackExchange.Exceptional.AspNetCore/StackExchange.Exceptional.AspNetCore.csproj

@@ -9,7 +9,7 @@
   <ItemGroup>
     <ProjectReference Include="../StackExchange.Exceptional.Shared/StackExchange.Exceptional.Shared.csproj" />
     <PackageReference Include="Microsoft.AspNetCore.Hosting.Abstractions" Version="2.0.0" />
-    <PackageReference Include="Microsoft.AspNetCore.Http.Abstractions" Version="2.0.0" />
+    <PackageReference Include="Microsoft.AspNetCore.Http" Version="2.0.0" />
     <PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="2.0.0" />
     <PackageReference Include="Microsoft.Extensions.Options" Version="2.0.0" />
   </ItemGroup>