From 2082726fe2d14890ff422e1e3a9ea1aa8db24b5f Mon Sep 17 00:00:00 2001
From: Andrew Gaul <gaul@google.com>
Date: Thu, 3 Feb 2022 10:03:37 +0900
Subject: [PATCH] Map errors to HTTP statuses (#666)

The initial motivation is to map ENAMETOOLONG from 500 Internal Error
to 400 Bad Request.  This prevents clients like gcsfuse from
unnecessarily retrying requests.  This commit also remove some panic
call paths.
---
 fakestorage/json_response.go | 12 ++++++++++++
 fakestorage/object.go        | 11 +++++++++--
 fakestorage/upload.go        |  8 ++++----
 3 files changed, 25 insertions(+), 6 deletions(-)

diff --git a/fakestorage/json_response.go b/fakestorage/json_response.go
index b4be2d93b1..b0f2f429dc 100644
--- a/fakestorage/json_response.go
+++ b/fakestorage/json_response.go
@@ -2,7 +2,10 @@ package fakestorage
 
 import (
 	"encoding/json"
+	"errors"
 	"net/http"
+	"os"
+	"syscall"
 )
 
 type jsonResponse struct {
@@ -53,3 +56,12 @@ func (r *jsonResponse) getErrorMessage(status int) string {
 	}
 	return http.StatusText(status)
 }
+
+func errToJsonResponse(err error) jsonResponse {
+	status := 0
+	var pathError *os.PathError
+	if errors.As(err, &pathError) && pathError.Err == syscall.ENAMETOOLONG {
+		status = http.StatusBadRequest
+	}
+	return jsonResponse{errorMessage: err.Error(), status: status}
+}
diff --git a/fakestorage/object.go b/fakestorage/object.go
index 21cad11b4a..a86a9036cb 100644
--- a/fakestorage/object.go
+++ b/fakestorage/object.go
@@ -556,7 +556,10 @@ func (s *Server) setObjectACL(r *http.Request) jsonResponse {
 		Role:   role,
 	}}
 
-	s.CreateObject(obj)
+	_, err = s.createObject(obj)
+	if err != nil {
+		return errToJsonResponse(err)
+	}
 
 	return jsonResponse{data: newACLListResponse(obj.ObjectAttrs)}
 }
@@ -607,7 +610,11 @@ func (s *Server) rewriteObject(r *http.Request) jsonResponse {
 		Content: append([]byte(nil), obj.Content...),
 	}
 
-	s.CreateObject(newObject)
+	_, err = s.createObject(newObject)
+	if err != nil {
+		return errToJsonResponse(err)
+	}
+
 	return jsonResponse{data: newObjectRewriteResponse(newObject.ObjectAttrs)}
 }
 
diff --git a/fakestorage/upload.go b/fakestorage/upload.go
index ab50369279..baeea7ede5 100644
--- a/fakestorage/upload.go
+++ b/fakestorage/upload.go
@@ -196,7 +196,7 @@ func (s *Server) simpleUpload(bucketName string, r *http.Request) jsonResponse {
 	}
 	obj, err = s.createObject(obj)
 	if err != nil {
-		return jsonResponse{errorMessage: err.Error()}
+		return errToJsonResponse(err)
 	}
 	return jsonResponse{data: obj}
 }
@@ -239,7 +239,7 @@ func (s *Server) signedUpload(bucketName string, r *http.Request) jsonResponse {
 	}
 	obj, err = s.createObject(obj)
 	if err != nil {
-		return jsonResponse{errorMessage: err.Error()}
+		return errToJsonResponse(err)
 	}
 	return jsonResponse{data: obj}
 }
@@ -319,7 +319,7 @@ func (s *Server) multipartUpload(bucketName string, r *http.Request) jsonRespons
 	}
 	obj, err = s.createObject(obj)
 	if err != nil {
-		return jsonResponse{errorMessage: err.Error()}
+		return errToJsonResponse(err)
 	}
 	return jsonResponse{data: obj}
 }
@@ -433,7 +433,7 @@ func (s *Server) uploadFileContent(r *http.Request) jsonResponse {
 		s.uploads.Delete(uploadID)
 		obj, err = s.createObject(obj)
 		if err != nil {
-			return jsonResponse{errorMessage: err.Error()}
+			return errToJsonResponse(err)
 		}
 	} else {
 		if _, no308 := r.Header["X-Guploader-No-308"]; no308 {