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使用golang进行kong限流插件开发

go lampnick 3322℃ 0评论

rate limiting限流仓库地址

https://github.com/lampnick/kong-rate-limiting-golang

前置条件

  1. 获取编译基础镜像（Go插件是使用-buildmode=plugin标志编译的，该标志允许插件服务器动态加载它们。） 
    docker pull kong/go-plugin-tool:latest-centos-7
  2. go-pluginserver可执行文件路径 
    默认路径：/usr/local/bin
自定义路径有两种方式：
1.环境变量增加go_pluginserver_exe
2.kong配置文件设置go_pluginserver_exe
  3. go_plugins_dir go插件目录 
    kong配置文件中设置go插件的路径，默认值为off，表明禁用go插件支持
  4. 将你编译好的go插件复制到go_plugins_dir
  5. 和lua插件开发一样，需要将你的go插件名称配置到plugins属性中，这样kong才会加载你的插件
  6. 允许你的go插件使用常规模式，可通过Admin API或者声明式配置文件管理

构建Go Plugin Server和你的go插件

go插件服务器（ Go Plugin Server ）是一个典型的go应用，可使用如下流程

  1. 初始化go.mod 
    
Nick-Mac:kong-go-plugin nick$ go mod init kong-go-plugin
go: creating new go.mod: module kong-go-plugin

Nick-Mac:kong-go-plugin nick$ cat go.mod
module kong-go-plugin

go 1.13

2. 获取Go Plugin Server

Nick-Mac:kong-go-plugin nick$ go get -d -v github.com/Kong/go-pluginserver
go: downloading github.com/Kong/go-pluginserver v0.5.1
go: extracting github.com/Kong/go-pluginserver v0.5.1
go: downloading github.com/Kong/go-pdk v0.5.0
go: extracting github.com/Kong/go-pdk v0.5.0

Nick-Mac:kong-go-plugin nick$ cat go.mod
module kong-go-plugin

go 1.13

require github.com/Kong/go-pluginserver v0.5.1 // indirect

3. 构建Go Plugin Server，会在当前目录下生成go-pluginserver可执行文件

Nick-Mac:kong-go-plugin nick$ go build github.com/Kong/go-pluginserver
go: finding github.com/Kong/go-pdk v0.5.0

Nick-Mac:kong-go-plugin nick$ ll
total 29952
drwxr-xr-x 5 nick staff 160B 9 7 11:23 .
drwxr-xr-x 9 nick staff 288B 9 7 11:14 ..
-rwxr-xr-x 1 nick staff 15M 9 7 11:23 go-pluginserver
-rw-r--r-- 1 nick staff 91B 9 7 11:20 go.mod
-rw-r--r-- 1 nick staff 1.2K 9 7 11:20 go.sum

4. 接下来将构建一个go插件，克隆下面的示例仓库，使用使用-buildmode plugin 进行构建，会在当前目录生成一个.so文件

1.克隆
Nick-Mac:kong-go-plugin-example nick$ git clone https://github.com/Kong/go-plugins.git
Cloning into 'go-plugins'...
remote: Enumerating objects: 35, done.
remote: Counting objects: 100% (35/35), done.
remote: Compressing objects: 100% (29/29), done.
remote: Total 35 (delta 13), reused 21 (delta 5), pack-reused 0
Unpacking objects: 100% (35/35), done.
2.切到示例目录
Nick-Mac:kong-go-plugin-example nick$ cd go-plugins/
3.查看有哪些文件
Nick-Mac:go-plugins nick$ ll
total 48
drwxr-xr-x 9 nick staff 288B 9 7 11:27 .
drwxr-xr-x 3 nick staff 96B 9 7 11:27 ..
drwxr-xr-x 12 nick staff 384B 9 7 11:27 .git
-rw-r--r-- 1 nick staff 166B 9 7 11:27 Makefile
-rw-r--r-- 1 nick staff 367B 9 7 11:27 README.md
-rw-r--r-- 1 nick staff 536B 9 7 11:27 go-hello.go
-rw-r--r-- 1 nick staff 1.2K 9 7 11:27 go-log.go
-rw-r--r-- 1 nick staff 82B 9 7 11:27 go.mod
-rw-r--r-- 1 nick staff 1.1K 9 7 11:27 go.sum
4.开始构建
Nick-Mac:go-plugins nick$ go build -buildmode plugin go-hello.go
5.查看文件多了一个go-hello.so
Nick-Mac:go-plugins nick$ ll
total 4960
drwxr-xr-x 10 nick staff 320B 9 7 11:30 .
drwxr-xr-x 3 nick staff 96B 9 7 11:27 ..
drwxr-xr-x 12 nick staff 384B 9 7 11:27 .git
-rw-r--r-- 1 nick staff 166B 9 7 11:27 Makefile
-rw-r--r-- 1 nick staff 367B 9 7 11:27 README.md
-rw-r--r-- 1 nick staff 536B 9 7 11:27 go-hello.go
-rw-r--r-- 1 nick staff 2.4M 9 7 11:30 go-hello.so
-rw-r--r-- 1 nick staff 1.2K 9 7 11:27 go-log.go
-rw-r--r-- 1 nick staff 82B 9 7 11:27 go.mod
-rw-r--r-- 1 nick staff 1.1K 9 7 11:27 go.sum


### 环境一致性约束
- 所有公共库需要版本一致
    - Kong/go-pdk
    - 所有go库文件 (像fmt, rpc, reflect等)
    - 操作系统库文件, 像libpthread, libc, ld-xxxx等
- go编译器版本完全一致
- go环境变量，像$GOROOT、$GOPATH等一致

典型的由于环境不一致出现的错误信息如下

failed to open plugin kong: plugin.Open("/path/go-plugins/go-hello"): plugin was built with a different version of package github.com/Kong/go-pdk/bridge


### 开发go插件

###### go插件开发流程
1. 定义一个结构体类型保存配置文件

用lua写的插件通过schema来指定怎样读取和验证来自数据库和Admin API中的配置数据。由于GO是静态类型语言，都需要用配置结构体定义
type MyConfig struct {
Path string //这里配置的会在konga添加插件时显示出来
Reopen bool
}
公有属性将会被配置数据填充，如果希望在数据库中使用不同的名称，可以使用encoding/json加tag的方式
type MyConfig struct {
Path string `json:my_file_path`
Reopen bool `json:reopen`
}

2. 使用New()创建一个实例

你的go插件必须定义一个名叫New的函数来创建这个类型的实例并返回一个interface{}类型
func New() interface{} {
return &MyConfig{}
}

3. 添加处理阶段方法

你可以在请求的生命周期的各个阶段实现自定义的逻辑。如在"access"阶段,定义一个名为Access的方法
func (conf MyConfig) Access (kong pdk.PDK) {
...
}
你可以实现自定义逻辑的阶段方法有如下几种
Certificate
Rewrite
Access
Preread
Log

4. 编译go插件
5. 将生成的.so文件放到go_plugins_dir定义的目录中

#### 部署
- kong配置文件修改

plugins = bundled,nick-rate-limiting
go_plugins_dir = /etc/kong/plugins
go_pluginserver_exe = /usr/local/bin/go-pluginserver

- 构建go-pluginserver

在go-pluginserver中执行go build github.com/Kong/go-pluginserver
会生成 go-pluginserver文件，复制到/usr/local/bin目录

-  编译go插件

go build -buildmode plugin custom-rate-limiting.go && cp custom-rate-limiting.so

- 将生成的.so文件放到go_plugins_dir定义的目录中
```.env
cp custom-rate-limiting.so ../plugins/</code></pre>
<ul>
<li>重启kong
<pre><code>
kong prepare && kong reload</code></pre></li>
<li>在konga中配置插件</li>
<li>测试请求是否正常，规则是否生效
<pre><code></code></pre></li>
</ul>
<h3>问题</h3>
<ul>
<li>kong start -c /etc/kong/kong.conf --vv时报错sh: /usr/local/bin/go-pluginserver: cannot execute binary file
<pre><code>由于在mac上交叉编译
解决方法：
直接在kong机器上编译go-pluginserver</code></pre></li>
<li>插件报错
<pre><code>
2020/09/07 15:35:52 failed to open plugin go-hello: plugin.Open("/etc/kong/plugins/go-hello.so"): /etc/kong/plugins/go-hello.so: invalid ELF header
nginx: [error] init_by_lua error: /usr/local/share/lua/5.1/kong/db/dao/plugins/go.lua:481: bad argument #1 to 'ipairs' (table expected, got nil)
stack traceback:
[C]: in function 'ipairs'
/usr/local/share/lua/5.1/kong/db/dao/plugins/go.lua:481: in function 'get_plugin'
/usr/local/share/lua/5.1/kong/db/dao/plugins/go.lua:515: in function 'load_plugin'
/usr/local/share/lua/5.1/kong/db/dao/plugins.lua:151: in function 'load_plugin_handler'
/usr/local/share/lua/5.1/kong/db/dao/plugins.lua:227: in function 'load_plugin'
/usr/local/share/lua/5.1/kong/db/dao/plugins.lua:275: in function 'load_plugin_schemas'
/usr/local/share/lua/5.1/kong/init.lua:484: in function 'init'
init_by_lua:3: in main chunk</code></pre></li>
</ul>
<p>stack traceback:
[C]: in function 'error'
/usr/local/share/lua/5.1/kong/cmd/start.lua:75: in function 'cmd_exec'
/usr/local/share/lua/5.1/kong/cmd/init.lua:88: in function </usr/local/share/lua/5.1/kong/cmd/init.lua:88>
[C]: in function 'xpcall'
/usr/local/share/lua/5.1/kong/cmd/init.lua:88: in function </usr/local/share/lua/5.1/kong/cmd/init.lua:45>
/usr/local/bin/kong:9: in function 'file_gen'
init_worker_by_lua:49: in function <init_worker_by_lua:47>
[C]: in function 'xpcall'
init_worker_by_lua:56: in function <init_worker_by_lua:54>
解决方案:
直接在kong机器上编译</p>
<pre><code>- 访问报错:message: "An unexpected error occurred"</code></pre>
<p>查看kong管理地址中错误日志路径
<a href="http://10.5.24.224:8001/">http://10.5.24.224:8001/</a>
"nginx_err_logs": "/usr/local/kong/logs/error.log",
tail -f /usr/local/kong/logs/error.log 日志报错如下
2020/09/07 16:21:22 [notice] 122415#0: <em>29 [kong] go.lua:97 go-pluginserver terminated: exit 0, context: ngx.timer
2020/09/07 16:21:22 [notice] 122415#0: </em>29 [kong] go.lua:86 Starting go-pluginserver, context: ngx.timer
2020/09/07 16:21:22 [crit] 122415#0: <em>29381 connect() to unix:/usr/local/kong/go_pluginserver.sock failed (2: No such file or directory), client: 10.5.216.251, server: kong, request: "GET /api/index.php?r=site/login-data HTTP/1.1", host: "hd.myscrm.cn:8000"
2020/09/07 16:21:22 [error] 122415#0: </em>29381 [kong] go.lua:140 [go-hello] trying to connect: no such file or directory, client: 10.5.216.251, server: kong, request: "GET /api/index.php?r=site/login-data HTTP/1.1", host: "hd.myscrm.cn:8000"
2020/09/07 16:21:22 [error] 122415#0: <em>29381 [kong] go.lua:429 [go-hello] starting instance: no such file or directory, client: 10.5.216.251, server: kong, request: "GET /api/index.php?r=site/login-data HTTP/1.1", host: "hd.myscrm.cn:8000"
2020/09/07 16:21:22 [error] 122415#0: </em>29381 lua coroutine: runtime error: /usr/local/share/lua/5.1/kong/db/dao/plugins/go.lua:432: no such file or directory
stack traceback:
coroutine 0:
[C]: in function 'error'
/usr/local/share/lua/5.1/kong/db/dao/plugins/go.lua:432: in function 'get_instance'
/usr/local/share/lua/5.1/kong/db/dao/plugins/go.lua:498: in function </usr/local/share/lua/5.1/kong/db/dao/plugins/go.lua:497>
coroutine 1:
[C]: in function 'resume'
coroutine.wrap:21: in function <coroutine.wrap:21>
/usr/local/share/lua/5.1/kong/init.lua:757: in function 'access'
access_by_lua(nginx-kong.conf:87):2: in main chunk, client: 10.5.216.251, server: kong, request: "GET /api/index.php?r=site/login-data HTTP/1.1", host: "hd.myscrm.cn:8000"
2020/09/07 16:21:22 [error] 122415#0: *29381 [kong] init.lua:759 [go-hello] /usr/local/share/lua/5.1/kong/db/dao/plugins/go.lua:432: no such file or directory, client: 10.5.216.251, server: kong, request: "GET /api/index.php?r=site/login-data HTTP/1.1", host: "hd.myscrm.cn:8000"</p>
<pre><code>
### 相关截图
- konga json配置</code></pre>
<pre><code>[{
    "type": "header,query,body",
    "key": "orderId",
    "value": "orderId1,orderId2,orderId3"
}, {
    "type": "query",
    "key": "username",
    "value": "nick,jack,star"
}]
```

  • konga 配置
    image

  • postman 显示header
    image

  • siege压测效果图
    image

转载请注明：MitNick » 使用golang进行kong限流插件开发

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