public static IApplicationBuilder UseHealthCheck(this IApplicationBuilder applicationBuilder)
  {
   return UseHealthCheck(applicationBuilder, new PathString("/api/health"));
  }

  public static IApplicationBuilder UseHealthCheck(this IApplicationBuilder applicationBuilder, string path)
  {
   return UseHealthCheck(applicationBuilder, new PathString(path));
  }

  public static IApplicationBuilder UseHealthCheck(this IApplicationBuilder applicationBuilder, PathString path)
  {
   applicationBuilder.Map(path, builder => builder.Use(
    (context, next) =>
    {
     context.Response.StatusCode = 200;
     return context.Response.WriteAsync("healthy");
    }));
   return applicationBuilder;
  }

  public static IApplicationBuilder UseHealthCheck(this IApplicationBuilder applicationBuilder, string path, Func<IServiceProvider, bool> checkFunc)
  {
   return UseHealthCheck(applicationBuilder, new PathString(path), serviceProvider => Task.FromResult(checkFunc(serviceProvider)));
  }

  public static IApplicationBuilder UseHealthCheck(this IApplicationBuilder applicationBuilder, string path,
   Func<IServiceProvider, Task<bool checkFunc)
  {
   return UseHealthCheck(applicationBuilder, new PathString(path), checkFunc);
  }

  public static IApplicationBuilder UseHealthCheck(this IApplicationBuilder applicationBuilder, PathString path, Func<IServiceProvider, bool> checkFunc)
  {
   if (checkFunc == null)
   {
    checkFunc = serviceProvider => true;
   }
   return UseHealthCheck(applicationBuilder, path, serviceProvider => Task.FromResult(checkFunc(serviceProvider)));
  }

  public static IApplicationBuilder UseHealthCheck(this IApplicationBuilder applicationBuilder, PathString path, Func<IServiceProvider, Task<bool checkFunc)
  {
   if (checkFunc == null)
   {
    checkFunc = serviceProvider => Task.FromResult(true);
   }
   applicationBuilder.Map(path, builder => builder.Use(
    async (context, next) =>
    {
     try
     {
      var healthy = await checkFunc.Invoke(context.RequestServices);
      if (healthy)
      {
       context.Response.StatusCode = StatusCodes.Status200OK;
       await context.Response.WriteAsync("healthy");
      }
      else
      {
       context.Response.StatusCode = StatusCodes.Status503ServiceUnavailable;
       await context.Response.WriteAsync("unhealthy");
      }
     }
     catch (Exception ex)
     {
      context.RequestServices.GetService<ILoggerFactory>().CreateLogger("HealthCheck").Error(ex);
      context.Response.StatusCode = StatusCodes.Status503ServiceUnavailable;
      await context.Response.WriteAsync("unhealthy");
     }
    }));
   return applicationBuilder;
  }

app.UseHealthCheck(); // 最基本的健康检查， 默认检查路径为 ""/api/health"，直接返回 healthy
app.UseHealthCheck("/heath"); // 配置健康检查的路径为 "/health"，直接返回 healthy

app.UseHealthCheck("/health", serviceProvider =>
 {
  // 检查数据连接是否正常，这里只是一个示例，可以根据需要自定义自己的实现
  var configuration = serviceProvider.GetService<IConfiguration>();
  var connString = configuration.GetConnectionString("DefaultConnection");
  try
  {
   using (var conn = new SqlConnection(connString))
   {
    conn.EnsureOpen();
   }
   return true;
  }
  catch (Exception)
  {
   return false;
  }
 });