kong个人分享(api网关)

# kong简介

## 背景

   我们在提供api或微服务时,通常借助openresty nginx进行流量转发或者添加一些规则或功能，但是随着服务数量和引用增多,复杂的网络环境，   使维护变得困难，不容易扩展，一些功能也会在多个服务中重复,我们期望有一个工具来集中管理。

   ![](images/kong_arch.png)

## 简介

Kong 是在客户端和（微）服务间转发API通信的API网关和API服务管理层,通过插件扩展功能。我们可以可以通过增加更多 Kong Server 机器对 Kong 服务进行水平扩展，通过前置的负载均衡器向这些机器分发请求。

* 官网:https://getkong.org/* github:https://github.com/Mashape/kong* kong-dashboard(开源UI):https://www.npmjs.com/package/kong-dashboard

## 特点

* Kong核心基于OpenResty构建，实现了请求/响应的Lua处理化* Kong通过Restful API提供了API/API消费者/插件/upstream/sni/证书的管理;* 数据中心用于存储Kong集群节点信息、API、消费者、插件等信息，目前提供了PostgreSQL和Cassandra支持，如果需要高可用建议使用Cassandra；* 缓存机制(为了避免每次查询数据库，Kong 在第一次请求之行时，尝试在本地的内存里做尽可能多的数据缓存。)、kong集群使kong具备高性能高可用.

## 结构 * admin: restful api<-->kong server<-(cache)-->db * client:port--->[kong server<--(cache)-->db]-->api

## 安装

* kong:0.11

```bash$ sudo yum install epel-release$ sudo yum install kong-community-edition-0.11.0.*.noarch.rpm --nogpgcheck```* PostgreSQL 9.4+ and Cassandra 3.x.x

```bashyum install postgresql96-server postgresql96-contrib  ```## 配置

* 配置文件

```bash/etc/kong/kong.conf   /usr/local/kong/nginx.conf/usr/local/kong/nginx-kong.conf```* 模板:

```bashkong_defaults.luanginx.luanginx_kong.lua```

## 表结构

## kong常用命令

* kong

```bashkong --vkong check /etc/kong/kong.confkong health -p /usr/local/kongkong version```* 初始化数据库，插件更新

```bashkong migrations up -c /etc/kong/kong.confkong migrations list -c /etc/kong/kong.confkong migrations reset -c /etc/kong/kong.conf```* 配置

```bashkong start -c /etc/kong/kong.conf -p /usr/local/kong --nginx-conf custom_nginx.template --run-migrations truekong start -c /etc/kong/kong.conf --nginx-conf custom_nginx.templatekong quit -p /usr/local/kongkong stop -p /usr/local/kongkong reload -c /etc/kong/kong.conf -p /usr/local/kong  --nginx-conf custom_nginx.template```

## Kong Admin API* method:[get\patch\put\delete]

* 管理项：[apis\upstreams\plugins\consumers\certificates\snis]

* 格式

```bashget:/apis/{name or id}get:/apis/patch:/apis/{name or id}put:/apis/delete:/apis/{name or id}```

* config

``` bashcurl http://localhost:8001/ |jq .curl http://localhost:8001/status |jq .```

* /apis/

``` bashcurl -H "Content-type: application/json" -X POST -d ‘{"name":"demo","hosts":"demo.com","upstream_url":"http://www.baidu.com"}‘ "http://localhost:8001/apis/" | jq .修改hosts-->reloadcurl -H "Content-type: application/json" -X POST -d ‘{"name":"demo","hosts":"demo.com","upstream_url":"http://structuretest.com","preserve_host":"false"}‘ "http://localhost:8001/apis/" | jq .

curl -H "Content-type: application/json" -X POST -d ‘{"name":"demo","hosts":"demo.com","upstream_url":"http://demo.upstream"}‘ "http://localhost:8001/apis/" | jq .curl -H "Content-type: application/json" -X PATCH -d ‘{"strip_uri":"true","preserve_host":"true", "https_only":"false","http_if_terminated":"true"}‘ "http://localhost:8001/apis/demo" |jq .curl -H "Content-type: application/json" -X POST -d ‘{"name":"demo","hosts":"demo.com","upstream_url":"http://demo.upstream"}‘ "http://localhost:8001/apis/" | jq .curl -X GET "http://localhost:8001/apis/demo" |jq .curl -X GET "http://localhost:8001/apis/" |jq .curl -X DELETE "http://localhost:8001/apis/demo" |jq .```

* /upstreams/

``` bashcurl -H "Content-type: application/json" -X POST -d ‘{"name":"demo.upstream","slots":10}‘ "http://localhost:8001/upstreams/" | jq .curl -X GET "http://localhost:8001/upstreams/demo.upstream" |jq .curl -X GET "http://localhost:8001/upstreams" |jq .curl -X DELETE "http://localhost:8001/upstreams/demo.upstream" |jq .```

* /upstreams/{name or id}/targets

``` bashcurl -H "Content-type: application/json" -X POST -d ‘{"target":"192.168.226.129:8090","weight":1}‘ "http://localhost:8001/upstreams/demo.upstream/targets" | jq .curl -X GET "http://localhost:8001/upstreams/test.upstream/targets" |jq .curl -X GET "http://localhost:8001/upstreams" |jq .

curl -X DELETE "http://localhost:8001/upstreams/test.upstream/targets/target"```

* /plugins/

``` bash--修改删除只能通过id;curl -H "Content-type: application/json" -X POST -d ‘{"name":"key-auth"}‘ "http://localhost:8001/apis/demo/plugins/" |jq .curl -H "Content-type: application/json" -X PATCH -d ‘{"enabled":"true","config.key_names":"apikey"}‘ "http://localhost:8001/apis/demo/plugins/9a14eea2-731b-48f7-8cb4-949ea9c0f25a" |jq .curl -X GET "http://localhost:8001/plugins/" |jq .curl -X GET "http://localhost:8001/apis/demo/plugins/" |jq .curl -X DELETE "http://localhost:8001/apis/demo/plugins/9a14eea2-731b-48f7-8cb4-949ea9c0f25a" |jq .```

* /consumers/

``` bashcurl -H "Content-type: application/json" -X POST -d ‘{"username":"demo-user"}‘ "http://localhost:8001/consumers/" |jq .curl  -X DELETE "http://localhost:8001/consumers/demo-user" |jq .curl  -X GET "http://localhost:8001/consumers/demo-user" |jq .添加key:curl -H "Content-type: application/json" -X POST -d ‘{"key":"api_key"}‘ "http://localhost:8001/consumers/demo-user/key-auth/" |jq .```

* /certificates/

``` bashcurl -H "Content-type: application/json" -X POST -d ‘{"cert":"","key":"","snis":""}‘ "http://localhost:8001/apis/demo/certificates/" |jq .``` 

* /snis/

``` bashcurl -H "Content-type: application/json" -X POST -d ‘{"name":"","ssl_certificate_id":""}‘ "http://localhost:8001/apis/demo/snis/" |jq .```

## proxy routing 规则

* 配置多项

``` bash备注：下面是接口响应格式{    "name": "my-api",    "upstream_url": "http://my-api.com",    "hosts": ["example.com", "service.com"],    "uris": ["/foo", "/bar"],    "methods": ["GET"]}```

* 遵循最长匹配优先评估,

``` bash"uris": ["/version/\d+/status/\d+"]"uris": ["/version"]"uris": ["/"]

--请求 GET /version/3/status/3  匹配第一个 GET /version 匹配第二个 GET /version/123 匹配第二个 GET /vs   匹配第三个```

## Load Balancing reference

* DNS based loadbalancing：dns_resolver配置dns ip，解析多个ip后，自动使用基于DNS负载均衡（加权负载均衡器,将做一个简单的循环）,当dns_stale_ttl 超时后请求dns；

* Ring-balancer：upstream（slots\orderlist）\ target(weight)

## 集群

* 0.11版本：当一个节点发生更新到数据库后，其他节点需要间隔db_update_frequency后，更新缓存失效字段。在使用Cassandra数据库db_update_propagation（数据节点传播延时）必须配置。为防止db_update_frequency后错过一个失效事件，db_cache_ttl全量更新cache

``` bashdb_update_frequency = 5  db_update_propagation = 0db_cache_ttl = 3600  ```

* 0.10版本：通过 Kong 集群，每个节点能够知道其它节点的存在。并且当一个Kong 节点有对数据更新，该节点有责任通知这个变化给集群里的其他节点，通知其其他节点把本地内存中的缓存无效，重新从数据库中获取更新后的数据。

``` bashcluster_listen    通信cluster_listen_rpc 代理通信cluster_advertisecluster_encrypt_key base64编码16字节加密集群通信cluster_keyring_filecluster_ttl_on_failure  //失败节点超时后停止被链接；cluster_profile  //local, lan, wan.

--数据库node表来存储节点信息： node VM_3_3_centos_0.0.0.0:7946_58b54877bc4a47d884b9986e71f49d8b | 10.100.3.3:7946           | 2017-08-07 04:29:05 VM_3_2_centos_0.0.0.0:7946_e4147c192bcc4401acf698ca6374d59d | 10.100.3.2:7946           | 2017-06-12 10:19:24```

## 常用插件

* 8个常用插件

## 编写插件

* 文件结构

``` bash

基本simple-plugin├── handler.lua  一个接口来实现。每个函数是由kong一个请求的生命周期所需的时刻。(对应lua模块的生命周期)└── schema.lua  插件引入参数类型、规则、校验

涉及数据库complete-plugin├── api.lua     与kong restful对接├── daos.lua   数据库操作├── handler.lua  //├── migrations  │   ├── cassandra.lua│   └── postgres.lua //kong migrations操作数据初始化└── schema.lua

```

* 编写rockspec文件:

```bashbuild = {  type = "builtin",  modules = {    ["kong.plugins.my-plugin-addtag.handler"] = "kong/plugins/my-plugin-addtag/handler.lua",    ["kong.plugins.my-plugin-addtag.schema"] = "kong/plugins/my-plugin-addtag/schema.lua"  }}```

```bashluarocks make --pack-binary-rock my-plugin-addtag-0.1.0-0.rockspec ```

* 修改kong.conf custom_plugins 挂载，重启;

## 测试环境使用情况

```bashhttp://172.16.17.9:5664/#/apis```