Export handling error response (#171)

api/server/error_response.go

@@ -1,14 +1,16 @@
 package server
 
 import (
+	"context"
+	"encoding/json"
 	"errors"
 	"net/http"
 	"runtime/debug"
 
 	"github.com/Sirupsen/logrus"
-	"github.com/gin-gonic/gin"
 	"github.com/fnproject/fn/api/models"
 	"github.com/fnproject/fn/api/runner/common"
+	"github.com/gin-gonic/gin"
 )
 
 // ErrInternalServerError returned when something exceptional happens.
@@ -19,15 +21,28 @@ func simpleError(err error) *models.Error {
 }
 
 func handleErrorResponse(c *gin.Context, err error) {
-	log := common.Logger(c.Request.Context())
+	HandleErrorResponse(c.Request.Context(), c.Writer, err)
+}
+
+// HandleErrorResponse used to handle response errors in the same way.
+func HandleErrorResponse(ctx context.Context, w http.ResponseWriter, err error) {
+	log := common.Logger(ctx)
+	var statuscode int
 	switch e := err.(type) {
 	case models.APIError:
 		if e.Code() >= 500 {
 			log.WithFields(logrus.Fields{"code": e.Code()}).WithError(e).Error("api error")
 		}
-		c.JSON(e.Code(), simpleError(e))
+		statuscode = e.Code()
 	default:
 		log.WithError(err).WithFields(logrus.Fields{"stack": string(debug.Stack())}).Error("internal server error")
-		c.JSON(http.StatusInternalServerError, simpleError(ErrInternalServerError))
+		statuscode = http.StatusInternalServerError
+		err = ErrInternalServerError
+	}
+	w.Header().Set("Content-Type", "application/json; charset=utf-8")
+	w.WriteHeader(statuscode)
+	err = json.NewEncoder(w).Encode(simpleError(err))
+	if err != nil {
+		log.WithError(err).Errorln("error encoding error json")
 	}
 }