From 99038a250c6297cbb0e3fcc2feed682a396ad36d Mon Sep 17 00:00:00 2001
From: Thomas Fankhauser <tommy@system8.io>
Date: Tue, 15 Aug 2017 15:37:54 +0200
Subject: [PATCH] Allow go idiomatic return of nil MountResponse, PathResponse
 and GetResponse on error from driver.

---
 volume/api.go      | 15 ++++++++++++---
 volume/api_test.go |  6 +++---
 2 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/volume/api.go b/volume/api.go
index 592a1e8..a72c646 100644
--- a/volume/api.go
+++ b/volume/api.go
@@ -185,7 +185,10 @@ func (h *Handler) initMux() {
 		}
 		res, err := h.driver.Path(req)
 		if err != nil {
-			res.Err = err.Error()
+			msg := err.Error()
+			res = &PathResponse{Err: msg}
+			sdk.EncodeResponse(w, res, msg)
+			return
 		}
 		sdk.EncodeResponse(w, res, "")
 	})
@@ -198,7 +201,10 @@ func (h *Handler) initMux() {
 		}
 		res, err := h.driver.Get(req)
 		if err != nil {
-			res.Err = err.Error()
+			msg := err.Error()
+			res = &GetResponse{Err: msg}
+			sdk.EncodeResponse(w, res, msg)
+			return
 		}
 		sdk.EncodeResponse(w, res, "")
 	})
@@ -221,7 +227,10 @@ func (h *Handler) initMux() {
 		log.Println("Entering go-plugins-helpers listPath")
 		res, err := h.driver.List()
 		if err != nil {
-			res.Err = err.Error()
+			msg := err.Error()
+			res = &ListResponse{Err: msg}
+			sdk.EncodeResponse(w, res, msg)
+			return
 		}
 		sdk.EncodeResponse(w, res, "")
 	})
diff --git a/volume/api_test.go b/volume/api_test.go
index 7332f65..d015375 100644
--- a/volume/api_test.go
+++ b/volume/api_test.go
@@ -157,7 +157,7 @@ func (p *testPlugin) Get(req *GetRequest) (*GetResponse, error) {
 			return &GetResponse{Volume: &Volume{Name: v}}, nil
 		}
 	}
-	return &GetResponse{}, fmt.Errorf("no such volume")
+	return nil, fmt.Errorf("no such volume")
 }
 
 func (p *testPlugin) List() (*ListResponse, error) {
@@ -187,7 +187,7 @@ func (p *testPlugin) Path(req *PathRequest) (*PathResponse, error) {
 			return &PathResponse{}, nil
 		}
 	}
-	return &PathResponse{}, fmt.Errorf("no such volume")
+	return nil, fmt.Errorf("no such volume")
 }
 
 func (p *testPlugin) Mount(req *MountRequest) (*MountResponse, error) {
@@ -197,7 +197,7 @@ func (p *testPlugin) Mount(req *MountRequest) (*MountResponse, error) {
 			return &MountResponse{}, nil
 		}
 	}
-	return &MountResponse{}, fmt.Errorf("no such volume")
+	return nil, fmt.Errorf("no such volume")
 }
 
 func (p *testPlugin) Unmount(req *UnmountRequest) error {