Ocelot + Consul实践

2018-03-01 12:22:30来源:cnblogs.com作者:桂素伟人点击

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关于Consul(https://www.consul.io)是一个分布式,高可用,支持多数据中心的服务发现和配置共享的服务软件,由 HashiCorp 公司用 Go 语言开发, 基于 Mozilla Public License 2.0 的协议进行开源。 在Consul的文档上,Consul 支持Service Discovery, Health Checking, Key/Value Store, Multi DataCenter。运用Consul,可以在系统中build复杂的应用和服务的发现等。本文不是Consul的学习重点,关于更多Consul的学习,可参考:http://blog.csdn.net/column/details/consul.html

阅读本博客的前提是对Consul中数据中心,节点,服务,健康检查等名词,一些基本的consul命令,Consul UI的使用有一定的了解。

Ocelot对Consul支持是天生集成,在OcelotGateway项目中configuration.json配置就可以开启consul+ocelot的使用,这套组合可以实现什么功能呢?

服务注册,服务发现,API网关(ocelot固有,不作说明),负载均衡,限流,熔错告警,弹性和瞬态故障处理

 

一、服务治理:服务注册,服务发现

服务注册和服务发现都是Consul自有的功能,可以通过Consul的http api完成注册或发现,我写了个NuGet库ConsulSharp(https://github.com/axzxs2001/ConsulSharp),可以在.net core下完成服务的注册和发现,建议服务注册做到一个统一的管理平台里,为了测试方便,可以在Consul的配置文里先配置服务,每次Consul启动时,自动注册;关于服务发现,Ocelot自动可以完成,只需要在OcelotGateway项目中configuration.json进行配置就可以,接下来我们看看怎么配置。

首先下载Consul: https://www.consul.io/downloads.html,本项目是windows下进行测试

再下载Consul配置文件(这个配置文件是适合本例Demo的,可根据具体给你个况调整)https://github.com/axzxs2001/Asp.NetCoreExperiment/tree/master/Asp.NetCoreExperiment/ConsulOcelot/consul

conf文件夹:consul存放配置文件

dist文件夹:consul UI,一个小的consul信息展示门户

data文件夹:consul启动后存放consul的生成的数据和文件,在运行consul前可以清空此文件夹

Consul的配置文件如下:

{  "encrypt": "7TnJPB4lKtjEcCWWjN6jSA==",  "services": [    {      "id": "API001",      "name": "API001",      "tags": [ "API001" ],      "address": "192.168.1.99",      "port": 5001,      "checks": [        {          "id": "API001_Check",          "name": "API001_Check",          "http": "http://192.168.1.99:5001/health",          "interval": "10s",          "tls_skip_verify": false,          "method": "GET",          "timeout": "1s"        }      ]    },    {      "id": "API002",      "name": "API002",      "tags": [ "API002" ],      "address": "192.168.1.99",      "port": 5002,      "checks": [        {          "id": "API002_Check",          "name": "API002_Check",          "http": "http://192.168.1.99:5002/health",          "interval": "10s",          "tls_skip_verify": false,          "method": "GET",          "timeout": "1s"        }      ]    }  ]}

两个服务API001和API002,跟着两个健康检查API001_Check和API002_Check

基于consul服务的配置,现在创建三个asp.net core web api项目

OcelotGateway,网关项目,端口5000;API001业务API项目,端口5001;业务API项目,API002端口5002,代码参见https://github.com/axzxs2001/Asp.NetCoreExperiment/tree/master/Asp.NetCoreExperiment/ConsulOcelot

OcelotGateway实现引入Ocelot网关,API001,API002实现健康检查的两个get请求。

测试服务注册和发现:

1、 启动consul

consul agent -server -datacenter=dc1 -bootstrap -data-dir ./data -config-file ./conf -ui-dir ./dist -node=n1 -bind 本机IP -client=0.0.0.0

再启动一个consul,查看状态,命令:consul operator raft list-peers

结果:

Node  ID                                    Address            State   Voter  RaftProtocol

n1    dad74de2-173d-1c1e-add0-975a243b59eb  192.168.1.99:8300  leader  true   3

用Consul UI查看

services:

 

nodes:

可以看到API001和API002服务,并且健康检查都是正常的。

2、 配置Ocelot网关

configuration.json文件如下(关于ocelot配置文件,详见http://ocelot.readthedocs.io/en/latest/features/configuration.html):

{  "ReRoutes": [    {      "DownstreamPathTemplate": "/api/values",      "DownstreamScheme": "http",      "DownstreamHostAndPorts": [        {          "Host": "localhost",          "Port": 5001        }      ],      "UpstreamPathTemplate": "/api001/values",      "UpstreamHttpMethod": [ "Get" ],      "ServiceName": "API001",      "LoadBalancer": "RoundRobin",      "UseServiceDiscovery": true,      "ReRouteIsCaseSensitive": false,      "QoSOptions": {        "ExceptionsAllowedBeforeBreaking": 3,        "DurationOfBreak": 10,        "TimeoutValue": 5000      },      "HttpHandlerOptions": {        "AllowAutoRedirect": false,        "UseCookieContainer": false,        "UseTracing": false      },      "AuthenticationOptions": {        "AuthenticationProviderKey": "",        "AllowedScopes": []      },      "RateLimitOptions": {        "ClientWhitelist": [ "admin" ],        "EnableRateLimiting": true,        "Period": "1m",        "PeriodTimespan": 15,        "Limit": 5      }    },    {      "DownstreamPathTemplate": "/notice",      "DownstreamScheme": "http",      "DownstreamHostAndPorts": [        {          "Host": "localhost",          "Port": 5001        }      ],      "UpstreamPathTemplate": "/notice",      "UpstreamHttpMethod": [ "Post" ],           "ReRouteIsCaseSensitive": false,      "QoSOptions": {        "ExceptionsAllowedBeforeBreaking": 3,        "DurationOfBreak": 10,        "TimeoutValue": 5000      },      "HttpHandlerOptions": {        "AllowAutoRedirect": false,        "UseCookieContainer": false,        "UseTracing": false      },      "AuthenticationOptions": {        "AuthenticationProviderKey": "",        "AllowedScopes": []      }       },    {      "DownstreamPathTemplate": "/api/values",      "DownstreamScheme": "http",      "DownstreamHostAndPorts": [        {          "Host": "localhost",          "Port": 5002        }      ],      "UpstreamPathTemplate": "/API002/values",      "UpstreamHttpMethod": [ "Get" ],      "QoSOptions": {        "ExceptionsAllowedBeforeBreaking": 3,        "DurationOfBreak": 10,        "TimeoutValue": 5000      },      "ServiceName": "API002",      "LoadBalancer": "RoundRobin",      "UseServiceDiscovery": true,      "HttpHandlerOptions": {        "AllowAutoRedirect": false,        "UseCookieContainer": false      },      "AuthenticationOptions": {        "AuthenticationProviderKey": "",        "AllowedScopes": []      },      "RateLimitOptions": {        "ClientWhitelist": [ "user" ],        "EnableRateLimiting": true,        "Period": "1m",        "PeriodTimespan": 15,        "Limit": 5      }    }  ],  "GlobalConfiguration": {    "ServiceDiscoveryProvider": {      "Host": "localhost",      "Port": 8500    },    "RateLimitOptions": {      "ClientIdHeader": "client_id",      "QuotaExceededMessage": "Too Many Requests!!!",      "DisableRateLimitHeaders": false    }  }}

启动OcelotGateway,API001,API002项目,通过http://localhost:5000/api001/values,和http://localhost:5000/api002/values访问;因为Ocelot配置了Consul的服务治理,所以可以通过配置的服务名称和GlobalConfiguratin的Consul http api接口查找到对应服务的地址,进行访问,这些都是Ocelot帮我们做,这点很容易证明,可以修改Consul配置文件中服务的address为错误IP,就会发现通过5000端口访问不成功。

二、负载均衡

负载均衡需要启动多个API001和API002,才能进行测试,所以发布API001和API002项目,并复制到一个与192.168.1.99在一个局域网的电脑中,同时把Consul和它的配置,UI文件也复制到这台电脑上,网关项目OcelotGateway不需要,假设另外一台电脑为192.168.1.126

首先修改Consul的配置文件如下

{  "encrypt": "7TnJPB4lKtjEcCWWjN6jSA==",  "services": [    {      "id": "API001",      "name": "API001",      "tags": [ "API001" ],      "address": "192.168.1.126",      "port": 5001,      "checks": [        {          "id": "API001_Check",          "name": "API001_Check",          "http": "http://192.168.1.126:5001/health",          "interval": "10s",          "tls_skip_verify": false,          "method": "GET",          "timeout": "1s"        }      ]    },    {      "id": "API002",      "name": "API002",      "tags": [ "API002" ],      "address": "192.168.1.126",      "port": 5002,      "checks": [        {          "id": "API002_Check",          "name": "API002_Check",          "http": "http://192.168.1.126:5002/health",          "interval": "10s",          "tls_skip_verify": false,          "method": "GET",          "timeout": "1s"        }      ]    }  ]}

在192.168.1.126下启动API001,API002项目

启动consul

consul agent -server -datacenter=dc1 -data-dir ./data -config-file ./conf -ui-dir ./dist -node=n2 -bind 192.168.1.126

同样,在192.168.1.126下用Consul UI查看各服务是否正常

在192.168.1.99下,把192.168.1.126加到集群中,命令如下

consul join 192.168.1.126

注意,consul集群中,consul配置文件中的encrypt,一定要相同,否则无法放加入同一个集群

用consul operator raft list-peers查看状态,会发现n1,n2在一个集群中了

Node  ID                                    Address             State     Voter  RaftProtocol

n1    dad74de2-173d-1c1e-add0-975a243b59eb  192.168.1.99:8300   leader    true   3

n2    efe954ce-9840-5c66-fa80-b9022167d782  192.168.1.126:8300  follower  true   3

些时在浏览器中多次访问view-source:http://localhost:5000/api001/values或view-source:http://localhost:5000/api002/values,会发现返回的内容是交替出现的,因为只有两个相同的API在集群中,这样就实现了负载均衡。

 

三、限流

限流是通过configuration.json配置完成的,具体值详见http://ocelot.readthedocs.io/en/latest/features/ratelimiting.html

每个要限流Route中

  

    "RateLimitOptions": {        "ClientWhitelist": [ "admin" ],        "EnableRateLimiting": true,        "Period": "1m",        "PeriodTimespan": 15,        "Limit": 5      }
GlobalConfiguration中    "RateLimitOptions": {      "ClientIdHeader": "client_id",      "QuotaExceededMessage": "too more request",      "DisableRateLimitHeaders": false}

需要说明的是如果配置ClientWithelist白名单,需要在访问api的客户端添加一个Header项目,key为client_id,值为admin,此客户端就不受限流控制

为了测试限流创建 TestClient控制台程序进行测试,交果如下图,在一分钟内,用adminclinet访问API001超过五次也可以,访问API002,只能五次

 

四、熔错告警

熔断保护在Consul中和Ocelot中都有实现,意义当一个服务不正常时,首先不影响正常使用(因为服务作了集群,可以把请求转到别的服务器上),二是发生问题,应该用所告警。Ocelot负载均衡可以自动发现服务出问题(Consul有健检查),并停止对异常服务请求;告警是通过Consul配置文件实现的,关于watches参看https://www.consul.io/docs/agent/watches.html

{  "watches": [    {      "type": "checks",      "handler_type": "http",      "state": "critical",      "http_handler_config": {        "path": "http://192.168.1.99:5000/notice",        "method": "POST",        "timeout": "10s",        "header": { "Authorization": [ "token" ] }      }    }  ]}

在consul启动时,会加载conf下的所有json文件,因为是json内容是watches节点,consul会作特定处理。

同时http://192.168.1.99:5000/notice映射的http://localhost:5001/notice中作了一个发邮件的操作,把发生异常的服务信息发送给对应邮箱,这里注意,测试时,不要关了API001测试,因为发邮件的功能在这个项目里,可以关掉API002测试,真实环境中,这块肯定是独立项目处理,并且采用集群的,效果如下:

 

关掉192.168.1.99下的API2,作业报警邮件会提示准确的检查错误和服务名称。

五、弹性和瞬态故障处理

弹性和瞬态故障处理,是Ocelot内置的功能,在网关转发每个请求时,会用Polly(https://github.com/App-vNext/Polly)处理,设置详见http://ocelot.readthedocs.io/en/latest/features/qualityofservice.html,开发上不作任何处理。

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