建议大家使用VS2019开发时把自带的反编译功能打开：
进入正题，首先上一个本节最终能实现的健康检测UI界面：
本节实现的健康检测是通过引用以下系列nuget进行的实现：
github上有该包的实现方式，使用过程中可以参考源码来编写相关参数，github地址：https://github.com/Xabaril/AspNetCore.Diagnostics.HealthChecks
在此也列一下清单吧，总共实现了对以下功能点的健康检测功能：
以上主要是些通用的检测点，如api是否正常，数据库、redis等存储库是否正常，rabbitmq是否正常等，除此之后我们还可以自己扩展，比如与我们系统业务相关的功能数据检测等，简单的实现估计也就几行代码，主要看需求。
如何实现web或api、数据库、redis等的状态检测呢？下面开始各种配置。
- 首先还是引用nuget包，我是引用了以下一堆，用哪个还是看需求：
- 配置Startup.cs文件：
1 public class Startup 2 { 3 public Startup(IConfiguration configuration) 4 { 5 Configuration = configuration; 6 } 7 public IConfiguration Configuration { get; } 8 9 public void ConfigureServices(IServiceCollection services) 10 { 11 services.AddCustomHealthCheck(this.Configuration); 12 13 services.AddHealthChecksUI(setupSettings => 14 { 15 //检测站点，可以添加多条，UI中会把站点内的检测点分组显示（也可通过配置文件实现） 16 setupSettings.AddHealthCheckEndpoint(name: "localhost-5000", uri: "http://localhost:5000/health"); 17 //当检测出异常结果时发送消息给api 18 setupSettings.AddWebhookNotification("webhook1", 19 uri: "http://localhost:5008/WeatherForecast/message", 20 payload: "{ "message": "Webhook report for [[LIVENESS]]: [[FAILURE]] - Description: [[DESCRIPTIONS]]"}", 21 restorePayload: "{ "message": "[[LIVENESS]] is back to life"}"); 22 setupSettings.SetMinimumSecondsBetweenFailureNotifications(60); 23 setupSettings.SetEvaluationTimeInSeconds(10); 24 }).AddSqlServerStorage(Configuration["HealthStorageConnectionString"]);//数据库持久化 25 //.AddInMemoryStorage();//内存持久化 26 } 27 28 public void ConfigureContainer(ContainerBuilder builder) 29 { 30 //autofac 31 } 32 33 // This method gets called by the runtime. Use this method to configure the HTTP request pipeline. 34 public void Configure(IApplicationBuilder app, IWebHostEnvironment env) 35 { 36 if (env.IsDevelopment()) 37 { 38 app.UseDeveloperExceptionPage(); 39 } 40 41 app.UseRouting(); 42 app.UseEndpoints(endpoints => 43 { 44 endpoints.MapHealthChecks("/health", new HealthCheckOptions() 45 { 46 Predicate = _ => true, 47 ResponseWriter = UIResponseWriter.WriteHealthCheckUIResponse 48 }); 49 endpoints.MapHealthChecksUI(); 50 }); 51 } 52 }
其中AddCustomHealthCheck的实现如下，实现的检测实例：
1 public static IServiceCollection AddCustomHealthCheck(this IServiceCollection services, IConfiguration configuration) 2 { 3 var hcBuilder = services.AddHealthChecks(); 4 5 hcBuilder.AddCheck("Jobs.MicrosoftBackgroundService-apiself", () => HealthCheckResult.Healthy()); 6 hcBuilder.AddSqlServer( 7 configuration["ConnectionString"], 8 name: "Jobs.MicrosoftBackgroundService-sqlserver-check", 9 tags: new string[] { "sqlserverdb" }); 10 hcBuilder.AddRabbitMQ( 11 $"amqp://{configuration["EventBusConnection"]}", 12 name: "Jobs.MicrosoftBackgroundService-rabbitmqbus-check", 13 tags: new string[] { "rabbitmqbus" }); 14 hcBuilder.AddRedis( 15 configuration["RedisConnectionString"], 16 name: "Jobs.MicrosoftBackgroundService-redis-check", 17 tags: new string[] { "redisdb" }); 18 hcBuilder.AddUrlGroup(new Uri(configuration["testApiUrl"]), name: "testApiUrl-check", tags: new string[] { "testApiUrl" }); 19 20 return services; 21 }
可以看到这里实现了对sqlserver数据库、rebbitmq、redis、webapi的健康检测，参数中最重要的是名称及配置如连接字符串的信息，如redis的连接字符串格式如何写，我们可以通过查看源码来了解，此处实现redis的健康检测源码如下：
1 using Microsoft.Extensions.Diagnostics.HealthChecks; 2 using StackExchange.Redis; 3 using System; 4 using System.Collections.Concurrent; 5 using System.Threading; 6 using System.Threading.Tasks; 7 8 namespace HealthChecks.Redis 9 { 10 public class RedisHealthCheck : IHealthCheck 11 { 12 private static readonly ConcurrentDictionary<string, ConnectionMultiplexer> _connections = new ConcurrentDictionary<string, ConnectionMultiplexer>(); 13 14 private readonly string _redisConnectionString; 15 16 public RedisHealthCheck(string redisConnectionString) 17 { 18 _redisConnectionString = (redisConnectionString ?? throw new ArgumentNullException("redisConnectionString")); 19 } 20 21 public async Task<HealthCheckResult> CheckHealthAsync(HealthCheckContext context, CancellationToken cancellationToken = default(CancellationToken)) 22 { 23 _ = 1; 24 try 25 { 26 if (!_connections.TryGetValue(_redisConnectionString, out ConnectionMultiplexer value)) 27 { 28 value = await ConnectionMultiplexer.ConnectAsync(_redisConnectionString); 29 if (!_connections.TryAdd(_redisConnectionString, value)) 30 { 31 value.Dispose(); 32 value = _connections[_redisConnectionString]; 33 } 34 } 35 36 await value.GetDatabase().PingAsync(); 37 return HealthCheckResult.Healthy(); 38 } 39 catch (Exception exception) 40 { 41 return new HealthCheckResult(context.Registration.FailureStatus, null, exception); 42 } 43 } 44 } 45 }
实现就几行的代码，同时我们看到这里是通过StackExchange.Redis实现的redis连接，我们传递的连接字符串就很明显了，如下：
"RedisConnectionString": "192.168.217.128:6379,defaultDatabase=1,password=123!@#..."
其他的相关参数也可以通过查看源码的方式来进行操作。。。
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设置数据持久化，可以通过查看源码得知此处是使用的EFCore，支持以下种类的持久化：
services中添加配置（记得引用需要的持久化nuget包）：
services.AddSqlServerStorage(Configuration["HealthStorageConnectionString"]);
程序启动后会自动根据配置的数据库连接信息创建数据表，大概就是配置信息、当前状态信息、历史记录信息。
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如果健康检测异常需要发送消息至api，可以添加以下配置：
具体参数格式也可通过源码查看，此处是post方式数据传输，关键源码如下：
1 foreach (var webHook in _settings.Webhooks) 2 { 3 bool shouldNotify = webHook.ShouldNotifyFunc?.Invoke(report) ?? true; 4 5 if (!shouldNotify) 6 { 7 _logger.LogInformation("Webhook notification will not be sent because of user configuration"); 8 continue; 9 }; 10 11 if (!isHealthy) 12 { 13 failure = webHook.CustomMessageFunc?.Invoke(report) ?? GetFailedMessageFromContent(report); 14 description = webHook.CustomDescriptionFunc?.Invoke(report) ?? GetFailedDescriptionsFromContent(report); 15 } 16 17 var payload = isHealthy ? webHook.RestoredPayload : webHook.Payload; 18 payload = payload.Replace(Keys.LIVENESS_BOOKMARK, name) 19 .Replace(Keys.FAILURE_BOOKMARK, failure) 20 .Replace(Keys.DESCRIPTIONS_BOOKMARK, description); 21 22 23 Uri.TryCreate(webHook.Uri, UriKind.Absolute, out var absoluteUri); 24 25 if (absoluteUri == null || !absoluteUri.IsValidHealthCheckEndpoint()) 26 { 27 Uri.TryCreate(_serverAddressesService.AbsoluteUriFromRelative(webHook.Uri), UriKind.Absolute, out absoluteUri); 28 } 29 30 await SendRequest(absoluteUri, webHook.Name, payload); 31 }
可以看到此处的Webhooks可以配置多个
1 private async Task SendRequest(Uri uri, string name, string payloadContent) 2 { 3 try 4 { 5 var payload = new StringContent(payloadContent, Encoding.UTF8, Keys.DEFAULT_RESPONSE_CONTENT_TYPE); 6 var response = await _httpClient.PostAsync(uri, payload); 7 if (!response.IsSuccessStatusCode) 8 { 9 _logger.LogError("The webhook notification has not executed successfully for {name} webhook. The error code is {statuscode}.", name, response.StatusCode); 10 } 11 12 } 13 catch (Exception exception) 14 { 15 _logger.LogError($"The failure notification for {name} has not executed successfully.", exception); 16 } 17 }
我们可以通过api接收异常消息后添加日志或进行发送邮件等提醒信息。
最后如果要配置UI界面，只需在endpoint中添加配置：
1 app.UseEndpoints(endpoints => 2 { 3 endpoints.MapHealthChecks("/health", new HealthCheckOptions() 4 { 5 Predicate = _ => true, 6 ResponseWriter = UIResponseWriter.WriteHealthCheckUIResponse 7 });//要进行该站点检测应添加此代码 8 endpoints.MapHealthChecksUI();//添加UI界面支持 9 });
写的比较散，希望对大家学习有一丝丝帮助~~