Log tenantid header values if more than one provided.

src/Volo.Abp.AspNetCore.MultiTenancy/Volo/Abp/AspNetCore/MultiTenancy/HeaderTenantResolver.cs

@@ -1,5 +1,7 @@
 using System.Linq;
 using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Logging;
 using Volo.Abp.MultiTenancy;
 using Volo.ExtensionMethods.Collections.Generic;
 
@@ -9,13 +11,14 @@ namespace Volo.Abp.AspNetCore.MultiTenancy
     {
         protected override string GetTenantIdOrNameFromHttpContextOrNull(ITenantResolveContext context, HttpContext httpContext)
         {
-            //TODO: Get first one if provided multiple values and write a log
             if (httpContext.Request.Headers.IsNullOrEmpty())
             {
                 return null;
             }
 
-            var tenantIdHeader = httpContext.Request.Headers[context.GetAspNetCoreMultiTenancyOptions().TenantIdKey];
+            var tenantIdKey = context.GetAspNetCoreMultiTenancyOptions().TenantIdKey;
+
+            var tenantIdHeader = httpContext.Request.Headers[tenantIdKey];
             if (tenantIdHeader == string.Empty || tenantIdHeader.Count < 1)
             {
                 return null;
@@ -23,7 +26,9 @@ namespace Volo.Abp.AspNetCore.MultiTenancy
 
             if (tenantIdHeader.Count > 1)
             {
-                
+                context.ServiceProvider.GetRequiredService<ILogger<HeaderTenantResolver>>().LogWarning(
+                    $"HTTP request includes more than one {tenantIdKey} header value. First one will be used. All of them: {tenantIdHeader.JoinAsString(", ")}"
+                    );
             }
 
             return tenantIdHeader.First();