From 3732f968d07be0458ac8859e82d99e7e84c96c20 Mon Sep 17 00:00:00 2001
From: Matthias Radestock <matthias.radestock@gmail.com>
Date: Sat, 20 Jun 2015 23:36:48 +0100
Subject: [PATCH] include image name in errors

The go docker client's ErrNoSuchImage does not include the image
name. However, it is imperative that this name appears in error
messages sent to clients, since the docker client, as of version
1.7.0, only automatically pulls images when their name is present in
the error.

Fixes #967.
---
 proxy/create_container_interceptor.go | 15 ++++++++++++++-
 proxy/proxy_intercept.go              |  7 +++----
 2 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/proxy/create_container_interceptor.go b/proxy/create_container_interceptor.go
index cf7e0f22..e12d5fa4 100644
--- a/proxy/create_container_interceptor.go
+++ b/proxy/create_container_interceptor.go
@@ -21,6 +21,17 @@ type createContainerRequestBody struct {
 	MacAddress string             `json:"MacAddress,omitempty" yaml:"MacAddress,omitempty"`
 }
 
+// Replacement for docker.NoSuchImage, which does not contain the
+// image name, which in turn breaks docker clients post 1.7.0 since
+// they expect the image name to be present in errors.
+type ErrNoSuchImage struct {
+	Name string
+}
+
+func (err *ErrNoSuchImage) Error() string {
+	return "No such image: " + err.Name
+}
+
 func (i *createContainerInterceptor) InterceptRequest(r *http.Request) error {
 	body, err := ioutil.ReadAll(r.Body)
 	if err != nil {
@@ -63,7 +74,9 @@ func (i *createContainerInterceptor) InterceptRequest(r *http.Request) error {
 func (i *createContainerInterceptor) setWeaveWaitEntrypoint(container *docker.Config) error {
 	if len(container.Entrypoint) == 0 {
 		image, err := i.proxy.client.InspectImage(container.Image)
-		if err != nil {
+		if err == docker.ErrNoSuchImage {
+			return &ErrNoSuchImage{container.Image}
+		} else if err != nil {
 			return err
 		}
 
diff --git a/proxy/proxy_intercept.go b/proxy/proxy_intercept.go
index 080872f4..69f83c83 100644
--- a/proxy/proxy_intercept.go
+++ b/proxy/proxy_intercept.go
@@ -16,11 +16,10 @@ import (
 
 func (proxy *Proxy) Intercept(i interceptor, w http.ResponseWriter, r *http.Request) {
 	if err := i.InterceptRequest(r); err != nil {
-		_, isNoSuchContainer := err.(*docker.NoSuchContainer)
-		switch {
-		case isNoSuchContainer:
+		switch err.(type) {
+		case *docker.NoSuchContainer:
 			http.Error(w, err.Error(), http.StatusNotFound)
-		case err == docker.ErrNoSuchImage:
+		case *ErrNoSuchImage:
 			http.Error(w, err.Error(), http.StatusNotFound)
 		default:
 			http.Error(w, err.Error(), http.StatusInternalServerError)