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本文主要研究一下dubbo-go-proxy的plugins
PluginsGroup
dubbo-go-proxy-filter@v0.1.0-rc1.0.20210120132524-c63f4eb13725/pkg/api/config/api_config.go
// PluginsGroup defines the plugins group info
type PluginsGroup struct {
GroupName string `json:"groupName" yaml:"groupName"`
Plugins []Plugin `json:"plugins" yaml:"plugins"`
}
type Plugin struct {
Name string `json:"name" yaml:"name"`
Version string `json:"version" yaml:"version"`
Priority int `json:"priority" yaml:"priority"`
ExternalLookupName string `json:"externalLookupName" yaml:"externalLookupName"`
}PluginsGroup定义了GroupName和Plugins；Plugin定义了Name、Version、Priority、ExternalLookupName属性
PluginsWithFunc
dubbo-go-proxy/pkg/filter/plugins/plugins.go
type PluginsWithFunc struct {
Name string
Priority int
fn context.FilterFunc
}PluginsWithFunc定义了Name、Priority、context.FilterFunc属性
InitPluginsGroup
dubbo-go-proxy/pkg/filter/plugins/plugins.go
// InitPluginsGroup prase api_config.yaml(pluginsGroup) to map[string][]PluginsWithFunc
func InitPluginsGroup(groups []config.PluginsGroup, filePath string) {
if "" == filePath || len(groups) == 0 {
return
}
// load file.so
pls, err := plugin.Open(filePath)
if nil != err {
panic(err)
}
for _, group := range groups {
pwdMap := make(map[string]PluginsWithFunc, len(group.Plugins))
// trans to context.FilterFunc
for _, pl := range group.Plugins {
pwf := PluginsWithFunc{pl.Name, pl.Priority, loadExternalPlugin(&pl, pls)}
pwdMap[pl.Name] = pwf
}
groupWithPluginsMap[group.GroupName] = pwdMap
}
}InitPluginsGroup根据配置文件及filePath来初始化PluginsGroup；它通过plugin.Open(filePath)来加载plugin，之后遍历配置的groups，按groupName来加载对应的plugin map，它使用PluginsWithFunc来描述包装plugin，通过loadExternalPlugin方法来设置context.FilterFunc
loadExternalPlugin
dubbo-go-proxy/pkg/filter/plugins/plugins.go
func loadExternalPlugin(p *config.Plugin, pl *plugin.Plugin) context.FilterFunc {
if nil != p {
logger.Infof("loadExternalPlugin name is :%s,version:%s,Priority:%d", p.Name, p.Version, p.Priority)
sb, err := pl.Lookup(p.ExternalLookupName)
if nil != err {
panic(err)
}
sbf := sb.(func() filter.Filter)
logger.Infof("loadExternalPlugin %s success", p.Name)
return sbf().Do()
}
panic(errEmptyPluginConfig)
}loadExternalPlugin方法根据ExternalLookupName通过plugin的Lookup方法来加载对应的func，最后通过filter.Filter的Do方法返回context.FilterFunc
api_config.yaml
name: proxy description: proxy sample resources: - path: '/api/v1/test-dubbo/user' type: restful description: user plugins: groupNames: - group2 pluginNames: - rate limit - access methods: - httpVerb: GET onAir: true timeout: 1000ms inboundRequest: requestType: http queryStrings: - name: name required: true integrationRequest: requestType: http host: 127.0.0.1:8889 path: /UserProvider/GetUserByName mappingParams: - name: queryStrings.name mapTo: queryStrings.name group: "test" version: 1.0.0 - httpVerb: POST onAir: true timeout: 1000ms inboundRequest: requestType: http queryStrings: - name: name required: true integrationRequest: requestType: http host: 127.0.0.1:8889 path: /UserProvider/CreateUser group: "test" version: 1.0.0 pluginFilePath: "" pluginsGroup: - groupName: "group1" plugins: - name: "rate limit" version: "0.0.1" priority: 1000 externalLookupName: "ExternalPluginRateLimit" - name: "access" version: "0.0.1" priority: 1000 externalLookupName: "ExternalPluginAccess" - groupName: "group2" plugins: - name: "blacklist" version: "0.0.1" priority: 1000 externalLookupName: "ExternalPluginBlackList"
pluginsGroup定义了两个group，其中group1定义了ExternalPluginRateLimit、ExternalPluginAccess两个plugin；group2定义了ExternalPluginBlackList一个plugin
小结
dubbo-go-proxy的提供了plugins，它根据api_config.yaml定义的pluginFilePath及pluginsGroup来进行plugin的初始化；InitPluginsGroup方法先根据filePath加载plugin，之后通过loadExternalPlugin方法按ExternalLookupName来找到对应的context.FilterFunc。
doc
- dubbo-go-proxy
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