Startup.cs

using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using MultiTenant.Database;
using MultiTenant.Middleware;

namespace MultiTenant
{
    public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>(); // To access HttpContext
            services.AddDbContext<GlobalDbContext>(options => options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")));
            services.AddDbContext<TenantDbContext>();
            services.AddScoped<DbSeeder>();


            services.AddMvc();
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IHostingEnvironment env, DbSeeder dbSeeder)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
                dbSeeder.Seed();
            }

            app.UseTenantIdentifier();

            app.UseMvc();
        }
    }
}