MOSN 源码阅读 - 运行Plugin
通过阅读 MOSN 源码解析 - Plugin 机制，知道了 MOSN 的插件机制，具体如何运行起来 examples/codes/plugin/pluginfilter 呢？
- 本文基于 commit id: 50c777ff，把示例插件加入到
MOSN中。
原理
阅读文档可以知道主要是 MOSN 内部加载的 client 去调用 server，其中 client 是通过
源码:
func init() {
api.RegisterStream("pluginfilter", CreatePluginFilterFactory)
}
来注册的，server 则是通过
源码
func Register(name string, config *Config) (*Client, error)
来初始化客户端的。
修改代码
client 加入到 MOSN
通过查看代码，可以很容易发现 client 注册的时候实现如下接口
type StreamFilterChainFactory interface {
CreateFilterChain(context context.Context, callbacks StreamFilterChainFactoryCallbacks)
}
在 CreateFileChain 里面调用 Register 来初始化 client。
once.Do(func() {
var err error
// pluginfilter 是插件名称，和下面编译插件对应
client, err = plugin.Register("pluginfilter", nil)
if err != nil {
log.DefaultLogger.Errorf("plugin Register error: %v", err)
}
})
为了方便调试，对 examples/codes/plugin/pluginfilter/pluginfilter.go 做了如下修改，打印日志信息
82 body = response.GetBody()
83 if body != nil {
84 buf.Drain(buf.Len())
85 buf.Write(body)
86 }
+ 87 log.DefaultLogger.Infof("debug pluginfilter info") // 添加内容，打印一行日志查看调用过程
88 }
89 return api.StreamFilterContinue
90 }
为了把 pluginfilter 注册进去，所以在 cmd/mosn/main/mosn.go 里面的 import 添加
import (
......
_ "mosn.io/mosn/examples/codes/plugin/pluginfilter"
......
)
编译
进入项目根目录直接执行
插件
# champly @ champlydeiMac in ~/go/src/mosn.io/mosn on git:master x [10:30:06]
$ go build examples/codes/plugin/pluginfilter/server/pluginfilter.go
# champly @ champlydeiMac in ~/go/src/mosn.io/mosn on git:master x [10:30:38]
$ ll pluginfilter
-rwxr-xr-x 1 champly staff 23M 3 11 10:30 pluginfilter
- 如果名字不是
pluginfilter要修改，因为在代码里面写死了的
MOSN
# champly @ champlydeiMac in ~/go/src/mosn.io/mosn on git:master x [10:32:28] C:1
$ go build -o mosn ./cmd/mosn/main
# champly @ champlydeiMac in ~/go/src/mosn.io/mosn on git:master x [10:32:35]
$ ll mosn
-rwxr-xr-x 1 champly staff 35M 3 11 10:32 mosn
修改配置文件
添加 plugin 日志路径
{
"plugin": {
"log_base": "/tmp/" // 这里修改为可以创建的路径
}
.....
}
启动一个程序使其监听端口 2046
如 examples/codes/filter/commonrule/server.go，把 8080 修改为 2046
然后运行
go run ./examples/codes/filter/commonrule/server.go
运行
# champly @ champlydeiMac in ~/go/src/mosn.io/mosn on git:master x [10:38:19]
$ ./mosn start -c ./examples/codes/plugin/pluginfilter/config.json
2020-03-11 10:38:20,902 [INFO] [router] [Extend] [RegisterRouterRule] order is 1
2020-03-11 10:38:20,903 [INFO] [router] [Extend] [RegisterHandlerChain] order is 1
2020-03-11 10:38:20,904 [INFO] [config] processor added to configParsedCBMaps
2020-03-11 10:38:20,905 [INFO] [network] [ register pool factory] register protocol: Http1 factory
2020-03-11 10:38:20,905 [INFO] [network] [ register pool factory] register protocol: Http2 factory
2020-03-11 10:38:20,905 [INFO] [network] [ register pool factory] register protocol: SofaRpc factory
2020-03-11 10:38:20,906 [INFO] [network] [ register pool factory] register protocol: X factory
2020/03/11 10:38:20 load config from : ./examples/codes/plugin/pluginfilter/config.json
2020-03-11 10:38:20,907 [INFO] [mosn] [init tracing] disbale tracing
2020-03-11 10:38:20,908 [INFO] [server] [reconfigure] not reconfigure: dial unix /Users/champly/go/src/mosn.io/mosn/examples/codes/plugin/pluginfilter/reconfig.sock: connect: no such file or directory
2020-03-11 10:38:20,908 [INFO] [mosn] [NewMosn] new mosn created
2020-03-11 10:38:20,908 [INFO] [cluster] [cluster manager] [AddOrUpdatePrimaryCluster] cluster clientCluster updated
2020-03-11 10:38:20,908 [INFO] [upstream] [host set] update host, final host total: 1
2020-03-11 10:38:20,908 [INFO] [cluster] [primaryCluster] [UpdateHosts] cluster clientCluster update hosts: 1
2020-03-11 10:38:20,908 [INFO] mosn start xds client
2020-03-11 10:38:20,908 [WARN] [feature gate] feature XdsMtlsEnable is not enabled
2020-03-11 10:38:20,908 [WARN] [feature gate] feature PayLoadLimitEnable is not enabled
2020-03-11 10:38:20,908 [WARN] [feature gate] feature MultiTenantMode is not enabled
2020-03-11 10:38:20,908 [INFO] mosn parse registry info
2020-03-11 10:38:20,908 [INFO] mosn prepare for start
2020-03-11 10:38:20,909 [INFO] mosn start server
2020-03-11 10:38:20,909 [INFO] [admin store] [start service] start service Mosn Admin Server on [::]:34901
通过 curl 请求 localhost:2045
$ curl localhost:2045
Method: GET
Protocol: HTTP/1.1
Host: localhost:2045
RemoteAddr: 127.0.0.1:64765
RequestURI: "/"
URL: &url.URL{Scheme:"", Opaque:"", User:(*url.Userinfo)(nil), Host:"", Path:"/", RawPath:"", ForceQuery:false, RawQuery:"", Fragment:""}
Body.ContentLength: 0 (-1 means unknown)
Close: false (relevant for HTTP/1 only)
TLS: (*tls.ConnectionState)(nil)
Headers:
Accept: */*
User-Agent: curl/7.54.0
查看刚才配置的 plugin 路径，里面有一个 pluginfilter.log 文件，如果没有应该是权限不对
2020-03-11 10:39:07,525 [INFO] filter header:8, body:0, trailer:0
这个内容是 server/pluginfilter.go 记录的
然后查看 examples/codes/plugin/logs/mosn.log 会发现刚才我们修改的信息
2020-03-11 10:39:07,526 [INFO] debug pluginfilter info
分析
通过上面的操作，已经把第三方插件运行起来了，插件如何能生效，在什么地方生效呢？
查看配置文件
{
......
"stream_filters": [
{
"type": "pluginfilter"
}
]
......
}
stream_filters是通过api.RegisterStream注册的filter_chains是通过api.RegisterNetwork注册的
可以注入的位置，源码
type StreamFilterChainFactoryCallbacks interface {
AddStreamSenderFilter(filter StreamSenderFilter)
AddStreamReceiverFilter(filter StreamReceiverFilter, p FilterPhase)
// add access log per stream
AddStreamAccessLog(accessLog AccessLog)
}
const (
BeforeRoute FilterPhase = iota
AfterRoute
)
总结
通过阅读源码学习了很多，希望 MOSN 越来越强大。