元信息传递扩展
元信息透传是基于传输协议透传一些额外的 RPC 信息给下游,同时读取传输协议中上游透传的信息,透传字段需结合内部的治理能力,建议使用者自行扩展实现。
接口定义
// MetaHandler reads or writes metadata through certain protocol.
// The protocol will be a thrift.TProtocol usually.
type MetaHandler interface {
WriteMeta(ctx context.Context, msg Message) (context.Context, error)
ReadMeta(ctx context.Context, msg Message) (context.Context, error)
}
扩展示例
- ClientMetaHandler
package transmeta
var ClientTTHeaderHandler remote.MetaHandler = &clientTTHeaderHandler{}
// clientTTHeaderHandler implement remote.MetaHandler
type clientTTHeaderHandler struct{}
// WriteMeta of clientTTHeaderHandler writes headers of TTHeader protocol to transport
func (ch *clientTTHeaderHandler) WriteMeta(ctx context.Context, msg remote.Message) (context.Context, error) {
ri := msg.RPCInfo()
transInfo := msg.TransInfo()
hd := map[uint16]string{
transmeta.FromService: ri.From().ServiceName(),
transmeta.FromIDC: ri.From().DefaultTag(consts.IDC, ""),
transmeta.FromMethod: ri.From().Method(),
transmeta.ToService: ri.To().ServiceName(),
transmeta.ToMethod: ri.To().Method(),
transmeta.MsgType: strconv.Itoa(int(msg.MessageType())),
}
transInfo.PutTransIntInfo(hd)
if metainfo.HasMetaInfo(ctx) {
hd := make(map[string]string)
metainfo.SaveMetaInfoToMap(ctx, hd)
transInfo.PutTransStrInfo(hd)
}
return ctx, nil
}
// ReadMeta of clientTTHeaderHandler reads headers of TTHeader protocol from transport
func (ch *clientTTHeaderHandler) ReadMeta(ctx context.Context, msg remote.Message) (context.Context, error) {
ri := msg.RPCInfo()
remote := remoteinfo.AsRemoteInfo(ri.To())
if remote == nil {
return ctx, nil
}
transInfo := msg.TransInfo()
strInfo := transInfo.TransStrInfo()
ad := strInfo[transmeta.HeaderTransRemoteAddr]
if len(ad) > 0 {
// when proxy case to get the actual remote address
_ = remote.SetRemoteAddr(utils.NewNetAddr("tcp", ad))
}
return ctx, nil
}
-
添加该 ClientMetaHandler
cli, err := xxxservice.NewClient(targetService, client.WithMetaHandler(transmeta.ClientTTHeaderHandler))
最后修改
September 20, 2024
: doc: sync User Guide to Generic Call for Streaming [on trial] (#1140) (5641fba)