context: add ResponseError()

context.go

@@ -25,8 +25,9 @@ type Context struct {
 	Client  *Client
 	Message *Message
 
-	index    int
-	handlers []HandlerFunc
+	index       int
+	handlers    []HandlerFunc
+	responseErr interface{}
 }
 
 func (ctx *Context) Release() {
@@ -35,6 +36,10 @@ func (ctx *Context) Release() {
 	contextPool.Put(ctx)
 }
 
+func (ctx *Context) ResponseError() interface{} {
+	return ctx.responseErr
+}
+
 // Get returns value for key.
 func (ctx *Context) Get(key interface{}) (interface{}, bool) {
 	if len(ctx.Message.values) == 0 {
@@ -153,6 +158,10 @@ func (ctx *Context) write(v interface{}, isError bool, timeout time.Duration) er
 	if _, ok := v.(error); ok {
 		isError = true
 	}
+	if isError {
+		ctx.responseErr = v
+	}
+
 	rsp := newMessage(CmdResponse, req.method(), v, isError, req.IsAsync(), req.Seq(), cli.Handler, cli.Codec, ctx.Message.values)
 	return cli.PushMsg(rsp, timeout)
 }

context_test.go

@@ -5,6 +5,7 @@
 package arpc
 
 import (
+	"errors"
 	"testing"
 
 	"github.com/lesismal/arpc/codec"
@@ -110,3 +111,15 @@ func TestContext_Value(t *testing.T) {
 		t.Fatalf("Context.Value() value != 'value', have %v", value)
 	}
 }
+
+func TestContext_ResponseError(t *testing.T) {
+	ctx := &Context{
+		Client:  &Client{Handler: DefaultHandler},
+		Message: newMessage(CmdRequest, "test", nil, false, false, 0, DefaultHandler, codec.DefaultCodec, nil),
+	}
+	err := errors.New("test err")
+	ctx.Error(err)
+	if ctx.ResponseError() != err {
+		t.Fatalf("Context.ResponseError() != 'test err'")
+	}
+}