ASP.NET Core中实现健康检查

要实现运行状况检查，您需要在项目中安装 Microsoft.AspNetCore.Diagnostics.HealthChecks 。

接下来，在ConfigureServices方法中添加运行状况检查中间件。

public void ConfigureServices(IServiceCollection services)
{
    services.AddHealthChecks();
    services.AddControllers();
}

然后修改Configure方法，使用中间件:

public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{ 
    app.UseEndpoints(endpoints =>
    {
        endpoints.MapControllers();
        endpoints.MapHealthChecks("/health");
    });
}

现在，准备工作完成，运行程序然后访问 /health, 您将看到下边结果：

HealthCheckService

.NET Core提供了一个HealthCheckService类，我们可以把健康检查的放到我们的控制器中，就像这样：

public class HealthController : ControllerBase
{
    private readonly ILogger<HealthController> _logger;
    private readonly HealthCheckService _healthCheckService;
    public HealthController(ILogger<HealthController> logger,
        HealthCheckService healthCheckService)
    {
        _healthCheckService = healthCheckService;
        _logger = logger;
    }

    [HttpGet]
    public async Task<IActionResult> Get()
    {
        var report = await _healthCheckService.CheckHealthAsync();

        return report.Status == HealthStatus.Healthy ? Ok(report) :
            StatusCode((int)HttpStatusCode.ServiceUnavailable, report);
    }
}

现在，如果您尝试访问/health，您将看到相同的结果。

接下来，我们将实现数据库运行状态检查：

EntityFramework Core 健康检查

首先，还是需要安装Microsoft.Extensions.Diagnostics.HealthChecks.EntityFrameworkCore到我们的项目中。

接下来，我们拿到数据库上下文，然后修改代码：

public void ConfigureServices(IServiceCollection services)
{
    services.AddControllers();
    services.AddApiVersioning();
}

然后，运行程序，现在访问 /health 返回的结果是这样：

IHealthCheck

一些情况下，默认的健康检查可能不满足我们的需求，那么可以继承 IHealthCheck 接口，自定义我们的健康检查的逻辑。

public class ApiHealthCheck : IHealthCheck
{
    private readonly IHttpClientFactory _httpClientFactory;

    public ApiHealthCheck(IHttpClientFactory httpClientFactory)
    {
        _httpClientFactory = httpClientFactory;
    }
    public async Task<HealthCheckResult> CheckHealthAsync(HealthCheckContext context,
        CancellationToken cancellationToken = default)
    {
        using (var httpClient = _httpClientFactory.CreateClient())
        {
            var response = await httpClient.GetAsync("https://your-api-service.endpoint");
            if (response.IsSuccessStatusCode)
            {
                return HealthCheckResult.Healthy($"API is running.");
            }

            return HealthCheckResult.Unhealthy("API is not running");
        }
    }
}

然后修改代码如下：

public void ConfigureServices(IServiceCollection services)
{
    services.AddHealthChecks()
        .AddDbContextCheck<WeatherForecastDbContext>()
        .AddCheck<ApiHealthCheck>("ApiHealth");
    services.AddControllers();
}

然后，运行程序，访问 /health,结果如下：