如何給asp.net core寫個簡單的健康檢查

更新時間：2019年05月18日 13:13:20 作者：weihanli

這篇文章主要給大家介紹了關于如何給asp.net core寫個簡單的健康檢查的相關資料，文中通過示例代碼介紹的非常詳細，對大家學習或者使用asp.net core具有一定的參考學習價值，需要的朋友們下面來一起學習學習吧

Intro

健康檢查可以幫助我們知道應用的當前狀態(tài)是不是處于良好狀態(tài)，現(xiàn)在無論是 docker 還是 k8s 還是現(xiàn)在大多數(shù)的服務注冊發(fā)現(xiàn)大多都提供了健康檢查機制來檢測應用的健康狀態(tài)，如果應用本身就提供一個健康檢查的機制會更友好，更能真實的反映出應用的健康狀態(tài)。

我們的開發(fā)環(huán)境虛擬機配置有點低，所以有時候虛擬機會卡死。。導致接口無響應，有時可能有些服務啟動有問題會掛掉，所以需要一個簡單的健康檢查機制去檢查應用的健康狀態(tài)來第一時間知道應用出現(xiàn)異常。

健康檢查擴展實現(xiàn)

實現(xiàn)源碼

  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;
  }

配置健康檢查

在 Startup 里配置健康檢查，示例代碼

app.UseHealthCheck(); // 最基本的健康檢查， 默認檢查路徑為 ""/api/health"，直接返回 healthy
app.UseHealthCheck("/heath"); // 配置健康檢查的路徑為 "/health"，直接返回 healthy

app.UseHealthCheck("/health", serviceProvider =>
 {
  // 檢查數(shù)據(jù)連接是否正常，這里只是一個示例，可以根據(jù)需要自定義自己的實現(xiàn)
  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;
  }
 });

實際效果

直接啟動訪問 "/health"