Add Correlation Id Provider with Task

samples/3.1/MvcSample/DoNothingCorrelationIdProvider.cs

@@ -1,13 +1,11 @@
+using System.Threading.Tasks;
 using CorrelationId.Abstractions;
 using Microsoft.AspNetCore.Http;
 
 namespace MvcSample
 {
     public class DoNothingCorrelationIdProvider : ICorrelationIdProvider
     {
-        public string GenerateCorrelationId(HttpContext context)
-        {
-            return null;
-        }
+        public Task<string> GenerateCorrelationId(HttpContext _) => null;
     }
 }

src/CorrelationId/Abstractions/ICorrelationIdProvider.cs

@@ -1,4 +1,5 @@
-using Microsoft.AspNetCore.Http;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Http;
 
 namespace CorrelationId.Abstractions
 {
@@ -12,6 +13,6 @@ public interface ICorrelationIdProvider
         /// </summary>
         /// <param name="context">The <see cref="HttpContext"/> of the current request.</param>
         /// <returns>A string representing the correlation ID.</returns>
-        string GenerateCorrelationId(HttpContext context);
+        Task<string> GenerateCorrelationId(HttpContext context);
     }
 }

src/CorrelationId/CorrelationIdMiddleware.cs

@@ -80,7 +80,7 @@ public async Task Invoke(HttpContext context, ICorrelationContextFactory correla
 
             if (_options.IgnoreRequestHeader || RequiresGenerationOfCorrelationId(hasCorrelationIdHeader, cid))
             {
-                correlationId = GenerateCorrelationId(context);
+                correlationId = await GenerateCorrelationId(context);
             }
 
             if (!string.IsNullOrEmpty(correlationId) && _options.UpdateTraceIdentifier)
@@ -132,7 +132,7 @@ public async Task Invoke(HttpContext context, ICorrelationContextFactory correla
         private static bool RequiresGenerationOfCorrelationId(bool idInHeader, StringValues idFromHeader) =>
             !idInHeader || StringValues.IsNullOrEmpty(idFromHeader);
 
-        private string GenerateCorrelationId(HttpContext ctx)
+        private async Task<string> GenerateCorrelationId(HttpContext ctx)
         {
             string correlationId;
 
@@ -143,7 +143,7 @@ private string GenerateCorrelationId(HttpContext ctx)
                 return correlationId;
             }
 
-            correlationId = _correlationIdProvider.GenerateCorrelationId(ctx);
+            correlationId = await _correlationIdProvider.GenerateCorrelationId(ctx);
             Log.GeneratedHeaderUsingProvider(_logger, correlationId, _correlationIdProvider.GetType());
             return correlationId;
         }

src/CorrelationId/Providers/GuidCorrelationIdProvider.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Threading.Tasks;
 using CorrelationId.Abstractions;
 using Microsoft.AspNetCore.Http;
 
@@ -10,6 +11,6 @@ namespace CorrelationId.Providers
     public class GuidCorrelationIdProvider : ICorrelationIdProvider
     {
         /// <inheritdoc />
-        public string GenerateCorrelationId(HttpContext ctx) => Guid.NewGuid().ToString();
+        public Task<string> GenerateCorrelationId(HttpContext _) => Task.FromResult(Guid.NewGuid().ToString());
     }
 }

src/CorrelationId/Providers/TraceIdCorrelationIdProvider.cs

@@ -1,4 +1,5 @@
-using CorrelationId.Abstractions;
+using System.Threading.Tasks;
+using CorrelationId.Abstractions;
 using Microsoft.AspNetCore.Http;
 
 namespace CorrelationId.Providers
@@ -9,6 +10,6 @@ namespace CorrelationId.Providers
     public class TraceIdCorrelationIdProvider : ICorrelationIdProvider
     {
         /// <inheritdoc />
-        public string GenerateCorrelationId(HttpContext ctx) => ctx.TraceIdentifier;
+        public Task<string> GenerateCorrelationId(HttpContext ctx) => Task.FromResult(ctx.TraceIdentifier);
     }
 }

test/CorrelationId.Tests/CorrelationIdMiddlewareTests.cs

@@ -641,7 +641,7 @@ private class TestCorrelationIdProvider : ICorrelationIdProvider
         {
             public const string FixedCorrelationId = "TestCorrelationId";
 
-            public string GenerateCorrelationId(HttpContext context) => FixedCorrelationId;
+            public Task<string> GenerateCorrelationId(HttpContext context) => Task.FromResult(FixedCorrelationId);
         }
 
     }