From 112f5abdaeba476380404eef7772d7b90356a94b Mon Sep 17 00:00:00 2001
From: Rickard von Essen <rickard.von.essen@gmail.com>
Date: Wed, 11 Jan 2017 20:21:13 +0100
Subject: [PATCH] docker: Fix crash when performing log in to ECR with an
 invalid URL.

Closes #4383
---
 builder/docker/ecr_login.go | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/builder/docker/ecr_login.go b/builder/docker/ecr_login.go
index 1ee984763..6d2df0877 100644
--- a/builder/docker/ecr_login.go
+++ b/builder/docker/ecr_login.go
@@ -52,6 +52,9 @@ func (c *AwsAccessConfig) EcrGetLogin(ecrUrl string) (string, string, error) {
 
 	exp := regexp.MustCompile("(?:http://|https://|)([0-9]*)\\.dkr\\.ecr\\.(.*)\\.amazonaws\\.com.*")
 	splitUrl := exp.FindStringSubmatch(ecrUrl)
+	if len(splitUrl) != 3 {
+		return "", "", fmt.Errorf("Failed to parse the ECR URL: %s it should be on the form <account number>.dkr.ecr.<region>.amazonaws.com", ecrUrl)
+	}
 	accountId := splitUrl[1]
 	region := splitUrl[2]