Program.cs

using Microsoft.AspNetCore.Authentication.JwtBearer;
using Microsoft.IdentityModel.Tokens;
using System.Text;
using NLog;
using NLog.Web;
using System.Text;
using Microsoft.AspNetCore.Authentication.JwtBearer;
using Microsoft.IdentityModel.Tokens;
using System.Security.Claims;

var logger = NLog.LogManager.Setup().LoadConfigurationFromAppSettings().GetCurrentClassLogger();
logger.Debug("init main");

try
{
    var builder = WebApplication.CreateBuilder(args);

    string mySecret = Environment.GetEnvironmentVariable("Secret") ?? "none";
    string myIssuer = Environment.GetEnvironmentVariable("Issuer") ?? "none";

    logger.Info($"MySecret: {mySecret}, MyIssuer: {myIssuer}");
    
    builder.Services
        .AddAuthentication(JwtBearerDefaults.AuthenticationScheme)
        .AddJwtBearer(options =>
        {
            options.TokenValidationParameters = new TokenValidationParameters()
            {
                ValidateIssuer = true,
                ValidateAudience = false,
                ValidateLifetime = true,
                ValidateIssuerSigningKey = true,
                ValidIssuer = myIssuer,
                IssuerSigningKey =
                    new SymmetricSecurityKey(Encoding.UTF8.GetBytes(mySecret))
            };
        });

    // Add services to the container.

    builder.Services.AddControllers();
    // Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle
    builder.Services.AddEndpointsApiExplorer();
    builder.Services.AddSwaggerGen();

    builder.Services.AddAuthorization(options =>
    {
        options.AddPolicy("Admin", policy => policy.RequireClaim(ClaimTypes.Role, "admin"));
    });

    builder.Logging.ClearProviders();
    builder.Host.UseNLog();

    var app = builder.Build();

    // Configure the HTTP request pipeline.
    if (app.Environment.IsDevelopment())
    {
        app.UseSwagger();
        app.UseSwaggerUI();
    }

    app.UseHttpsRedirection();

    app.UseAuthorization();

    app.MapControllers();

    app.Run();

}
catch (System.Exception ex)
{
    logger.Error(ex, "Stopped program because of exception");
    throw;
}
finally
{
    NLog.LogManager.Shutdown();
}