序
本文主要研究一下dubbo-go-proxy的remoteFilter
remoteFilter
dubbo-go-proxy/pkg/filter/remote/call.go
func Init() {
extension.SetFilterFunc(constant.RemoteCallFilter, remoteFilterFunc())
}
func remoteFilterFunc() fc.FilterFunc {
return New(defaultNewParams()).Do()
}
func defaultNewParams() mockLevel {
mock := 1
mockStr := os.Getenv(constant.EnvMock)
if len(mockStr) > 0 {
i, err := strconv.Atoi(mockStr)
if err == nil {
mock = i
}
}
return mockLevel(mock)
}
type mockLevel int8
const (
open = iota
close
all
)
// clientFilter is a filter for recover.
type clientFilter struct {
level mockLevel
}
// New create timeout filter.
func New(level mockLevel) filter.Filter {
if level < 0 || level > 2 {
level = close
}
return &clientFilter{
level: level,
}
}clientFilter往extension注册了名为dgp.filters.remote_call的filter func；该func执行的是Do方法
Do
dubbo-go-proxy/pkg/filter/remote/call.go
func (f clientFilter) Do() fc.FilterFunc {
return func(c fc.Context) {
f.doRemoteCall(c.(*contexthttp.HttpContext))
}
}
func (f clientFilter) doRemoteCall(c *contexthttp.HttpContext) {
api := c.GetAPI()
if (f.level == open && api.Mock) || (f.level == all) {
c.SourceResp = &filter.ErrResponse{
Message: "mock success",
}
c.Next()
return
}
typ := api.Method.IntegrationRequest.RequestType
cli, err := matchClient(typ)
if err != nil {
c.Err = err
return
}
resp, err := cli.Call(client.NewReq(c.Ctx, c.Request, *api))
if err != nil {
logger.Errorf("[dubbo-go-proxy] client call err:%v!", err)
c.Err = err
return
}
logger.Debugf("[dubbo-go-proxy] client call resp:%v", resp)
c.SourceResp = resp
// response write in response filter.
c.Next()
}
func matchClient(typ config.RequestType) (client.Client, error) {
switch strings.ToLower(string(typ)) {
case string(config.DubboRequest):
return dubbo.SingletonDubboClient(), nil
case string(config.HTTPRequest):
return clienthttp.SingletonHTTPClient(), nil
default:
return nil, errors.New("not support")
}
}Do方法执行的是doRemoteCall，该方法辉县判断是否是mock，如果是则返回mock success；之后根据RequestType判断是否支持该请求类型并返回对应的client，最后通过cli.Call执行请求
Client
dubbo-go-proxy/pkg/client/client.go
type Client interface {
Init() error
Close() error
// Call invoke the downstream service.
Call(req *Request) (res interface{}, err error)
// MapParams mapping param, uri, query, body ...
MapParams(req *Request) (reqData interface{}, err error)
}Client接口定义了Init、Close、Call、MapParams方法，它有两个实现类，分别是dubbo.Client及http.Client
小结
dubbo-go-proxy的clientFilter往extension注册了名为dgp.filters.remote_call的filter func；该func执行的是Do方法，该方法根据RequestType判断是否支持该请求类型并返回对应的client，最后通过cli.Call执行请求。
doc
- dubbo-go-proxy
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