From 5aeb28dfee621f449560d3f2a6a8f25a92421b5a Mon Sep 17 00:00:00 2001
From: Asim Aslam <asim@aslam.me>
Date: Mon, 7 Jan 2019 09:11:36 +0000
Subject: [PATCH] Add error header

---
 client/rpc_codec.go | 18 ++++++++++++++++++
 server/rpc_codec.go | 17 ++++++++++++++++-
 2 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/client/rpc_codec.go b/client/rpc_codec.go
index 67959b6a..1a341a7c 100644
--- a/client/rpc_codec.go
+++ b/client/rpc_codec.go
@@ -3,6 +3,8 @@ package client
 import (
 	"bytes"
 	errs "errors"
+	"fmt"
+	"strconv"
 
 	"github.com/micro/go-micro/codec"
 	"github.com/micro/go-micro/codec/json"
@@ -112,6 +114,7 @@ func (c *rpcCodec) WriteRequest(req *request, body interface{}) error {
 		Method: req.ServiceMethod,
 		Type:   codec.Request,
 		Header: map[string]string{
+			"X-Micro-Id":      fmt.Sprintf("%d", req.Seq),
 			"X-Micro-Service": req.Service,
 			"X-Micro-Method":  req.ServiceMethod,
 		},
@@ -147,6 +150,21 @@ func (c *rpcCodec) ReadResponse(r *response, b interface{}) error {
 	r.Seq = me.Id
 	r.Error = me.Error
 
+	// check error in header
+	if len(me.Error) == 0 {
+		r.Error = me.Header["X-Micro-Error"]
+	}
+
+	// check method in header
+	if len(me.Method) == 0 {
+		r.ServiceMethod = me.Header["X-Micro-Method"]
+	}
+
+	if me.Id == 0 && len(me.Header["X-Micro-Id"]) > 0 {
+		id, _ := strconv.ParseInt(me.Header["X-Micro-Id"], 10, 64)
+		r.Seq = uint64(id)
+	}
+
 	if err != nil {
 		return errors.InternalServerError("go.micro.client.codec", err.Error())
 	}
diff --git a/server/rpc_codec.go b/server/rpc_codec.go
index f19b2782..6afc4e4b 100644
--- a/server/rpc_codec.go
+++ b/server/rpc_codec.go
@@ -2,6 +2,8 @@ package server
 
 import (
 	"bytes"
+	"fmt"
+	"strconv"
 
 	"github.com/micro/go-micro/codec"
 	"github.com/micro/go-micro/codec/grpc"
@@ -87,9 +89,17 @@ func (c *rpcCodec) ReadRequestHeader(r *request, first bool) error {
 	m.Target = m.Header["X-Micro-Service"]
 	m.Method = m.Header["X-Micro-Method"]
 
+	// set id
+	if len(m.Header["X-Micro-Id"]) > 0 {
+		id, _ := strconv.ParseInt(m.Header["X-Micro-Id"], 10, 64)
+		m.Id = uint64(id)
+	}
+
+	// read header via codec
 	err := c.codec.ReadHeader(&m, codec.Request)
 	r.ServiceMethod = m.Method
 	r.Seq = m.Id
+
 	return err
 }
 
@@ -104,11 +114,16 @@ func (c *rpcCodec) WriteResponse(r *response, body interface{}, last bool) error
 		Id:     r.Seq,
 		Error:  r.Error,
 		Type:   codec.Response,
-		Header: map[string]string{},
+		Header: map[string]string{
+			"X-Micro-Id":     fmt.Sprintf("%d", r.Seq),
+			"X-Micro-Method": r.ServiceMethod,
+			"X-Micro-Error":  r.Error,
+		},
 	}
 	if err := c.codec.Write(m, body); err != nil {
 		c.buf.wbuf.Reset()
 		m.Error = errors.Wrapf(err, "Unable to encode body").Error()
+		m.Header["X-Micro-Error"] = m.Error
 		if err := c.codec.Write(m, nil); err != nil {
 			return err
 		}