.NetCore之健康检查

1. 介绍

在开发AspNet Core应用的时候，我们经常会为该应用公布一个特殊的检测接口出来。该接口的目的很简单，告诉外界程序当前程序现在是可以访问或者不能访问的，便于外界做出相应的操作，比如监控报警，页面通知用户稍作等待等。.

2. 官方包使用

2.1 基本使用

注入

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

            services.AddHealthChecks();
        }

启用中间件

        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }

            app.UseRouting();

            app.UseAuthorization();

            app.UseEndpoints(endpoints =>
            {
                endpoints.MapControllers();
                # 通过访问地址加/health 进行访问
                endpoints.MapHealthChecks("/health");
            });
        }

2.2 目的性检查

    /// <summary>
    /// mysql健康检查
    /// </summary>
    public class MySQLHealthCheck : IHealthCheck
    {
        public async Task<HealthCheckResult> CheckHealthAsync(HealthCheckContext context, CancellationToken cancellationToken = default)
        {
            try
            {
                return await Task.FromResult(HealthCheckResult.Healthy()).ConfigureAwait(false);
            }
            catch
            {
                return await Task.FromResult(HealthCheckResult.Unhealthy("From Sql Serve")).ConfigureAwait(false);
            }
        }
    }

    /// <summary>
    /// redis健康检查
    /// </summary>
    public class RedisHealthCheck : IHealthCheck
    {
        public Task<HealthCheckResult> CheckHealthAsync(HealthCheckContext context, CancellationToken cancellationToken = default)
        {
            return Task.FromResult(HealthCheckResult.Healthy());
        }
    }

注入

        public void ConfigureServices(IServiceCollection services)
        {
            services.AddControllers();
            
            //只有当所有的检查器都返回为Healthy的时候，才会认为是健康。
            services.AddHealthChecks()
                .AddCheck<MySQLHealthCheck>("mysql_check")
                .AddCheck<RedisHealthCheck>("redis_check");
        }

Configure方法不需要操作，默认配置是当检查器都返回健康时候才认为是健康。

单个检查，有时候我们又想进行单个检查，那就需要在 endpoints 的配置中新增另外的路由映射规则:

        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
                app.UseSwagger();
                app.UseSwaggerUI(c => c.SwaggerEndpoint("/swagger/v1/swagger.json", "WebApplication7 v1"));
            }

            app.UseRouting();

            app.UseAuthorization();

            app.UseEndpoints(endpoints =>
            {
                endpoints.MapControllers();

                endpoints.MapHealthChecks("/mysqlhealth", new HealthCheckOptions() {//mysql
                    Predicate = s => s.Name.Equals("mysql_check"),
                    ResponseWriter = WriteResponse
                });

                endpoints.MapHealthChecks("/redishealth", new HealthCheckOptions() //redis
                {
                    Predicate = s => s.Name.Equals("redis_check"),
                    ResponseWriter = WriteResponse
                });
            });
        }
        /// <summary>
        /// 返回指定格式
        /// </summary>
        /// <param name="context"></param>
        /// <param name="result"></param>
        /// <returns></returns>
        private static Task WriteResponse(HttpContext context, HealthReport result)
        {
            context.Response.ContentType = "application/json";

            var json = new JObject(
                new JProperty("status", result.Status.ToString()),
                new JProperty("results", new JObject(result.Entries.Select(pair => new JProperty(pair.Key,
                    new JObject(new JProperty("status", pair.Value.Status.ToString()),
                        new JProperty("description", pair.Value.Description),
                        new JProperty("data", new JObject(pair.Value.Data.Select(
                            p => new JProperty(p.Key, p.Value))))))))));

            return context.Response.WriteAsync(json.ToString());
        }

通过访问地址：http://localhost:5000/mysqlhealth 查看mysql连接状态

通过访问地址：http://localhost:5000/redishealth 查看redis连接状态

.NetCore之健康检查

3. 第三包支持

3.1 介绍

是一个用于.NetCore健康检查的包，支持的版本有：5.0，3.1，3.0，2.2

GitHub：https://github.com/xabaril/AspNetCore.Diagnostics.HealthChecks

支持一些封装的检查

Sql Server
MySql
Oracle
Sqlite
RavenDB
Postgres
EventStore
RabbitMQ
IbmMQ
Elasticsearch
CosmosDb
Solr
Redis
SendGrid
System: Disk Storage, Private Memory, Virtual Memory, Process, Windows Service
Azure Service Bus: EventHub, Queue and Topics
Azure Storage: Blob, Queue and Table
Azure Key Vault
Azure DocumentDb
Azure IoT Hub
Amazon DynamoDb
Amazon S3
Google Cloud Firestore
Network: Ftp, SFtp, Dns, Tcp port, Smtp, Imap, Ssl
MongoDB
Kafka
Identity Server
Uri: single uri and uri groups
Consul
Hangfire
SignalR
Kubernetes
ArangoDB
Gremlin

对应的Nuget包为

Install-Package AspNetCore.HealthChecks.System
Install-Package AspNetCore.HealthChecks.Network
Install-Package AspNetCore.HealthChecks.SqlServer
Install-Package AspNetCore.HealthChecks.MongoDb
Install-Package AspNetCore.HealthChecks.Npgsql
Install-Package AspNetCore.HealthChecks.Elasticsearch
Install-Package AspNetCore.HealthChecks.CosmosDb
Install-Package AspNetCore.HealthChecks.Solr
Install-Package AspNetCore.HealthChecks.Redis
Install-Package AspNetCore.HealthChecks.EventStore
Install-Package AspNetCore.HealthChecks.AzureStorage
Install-Package AspNetCore.HealthChecks.AzureServiceBus
Install-Package AspNetCore.HealthChecks.AzureKeyVault
Install-Package AspNetCore.HealthChecks.Azure.IoTHub
Install-Package AspNetCore.HealthChecks.MySql
Install-Package AspNetCore.HealthChecks.DocumentDb
Install-Package AspNetCore.HealthChecks.SqLite
Install-Package AspNetCore.HealthChecks.RavenDB
Install-Package AspNetCore.HealthChecks.Kafka
Install-Package AspNetCore.HealthChecks.RabbitMQ
Install-Package AspNetCore.HealthChecks.IbmMQ
Install-Package AspNetCore.HealthChecks.OpenIdConnectServer
Install-Package AspNetCore.HealthChecks.DynamoDB
Install-Package AspNetCore.HealthChecks.Oracle
Install-Package AspNetCore.HealthChecks.Uris
Install-Package AspNetCore.HealthChecks.Aws.S3
Install-Package AspNetCore.HealthChecks.Consul
Install-Package AspNetCore.HealthChecks.Hangfire
Install-Package AspNetCore.HealthChecks.SignalR
Install-Package AspNetCore.HealthChecks.Kubernetes
Install-Package AspNetCore.HealthChecks.Gcp.CloudFirestore
Install-Package AspNetCore.HealthChecks.SendGrid
Install-Package AspNetCore.HealthChecks.ArangoDb
Install-Package AspNetCore.HealthChecks.Gremlin

3.2 基本使用

本次事例来演示一个带UI界面的健康监控的基本使用，需要以下nuget包

    <PackageReference Include="AspNetCore.HealthChecks.UI" Version="5.0.1" />
    <PackageReference Include="AspNetCore.HealthChecks.UI.Client" Version="5.0.1" />
    <PackageReference Include="AspNetCore.HealthChecks.UI.InMemory.Storage" Version="5.0.1" />

部分代码使用上述的例子

注入

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

            services.AddHealthChecks()
                .AddCheck<MySQLHealthCheck>("mysql_check")
                .AddCheck<RedisHealthCheck>("redis_check");

            services.AddHealthChecksUI().AddInMemoryStorage();
        }

使用

        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }

            app.UseRouting();

            app.UseAuthorization();

            app.UseEndpoints(endpoints =>
            {
                endpoints.MapControllers();

                endpoints.MapHealthChecks("/mysqlhealth", new HealthCheckOptions()
                {
                    Predicate = s => s.Name.Equals("mysql_check"),
                    ResponseWriter = UIResponseWriter.WriteHealthCheckUIResponse
                });

                endpoints.MapHealthChecks("/redishealth", new HealthCheckOptions()
                {
                    Predicate = s => s.Name.Equals("redis_check"),
                    ResponseWriter = UIResponseWriter.WriteHealthCheckUIResponse
                });

                endpoints.MapHealthChecksUI();
            });
        }

配置文件

{
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft": "Warning",
      "Microsoft.Hosting.Lifetime": "Information"
    }
  },
  "HealthChecksUI": {
    "HealthChecks": [
      {
        "Name": "HTTP-Api-mysqlhealth",
        "Uri": "/mysqlhealth"//新版本可以使用相对路径
      },
      {
        "Name": "HTTP-Api-redishealth",
        "Uri": "/redishealth"
      }
    ],
    "Webhooks": [
      {
        "Name": "",
        "Uri": "",
        "Payload": "",
        "RestoredPayload": ""
      }
    ],
    "EvaluationTimeInSeconds": 10,//轮询间隔
    "MinimumSecondsBetweenFailureNotifications": 60
  },
  "AllowedHosts": "*"
}

启动程序访问：/healthchecks-ui 地址

通过该UI界面可以直观查看哪些监控服务出现问题

4. 参考文档

AspNetCore的HealthCheck ：https://blog.csdn.net/uoyo_blog/article/details/104811948/