From 6aee9528e1c6bc6164c8fa4f77e6148d7b06c0ae Mon Sep 17 00:00:00 2001
From: Justin Santa Barbara <justin@fathomdb.com>
Date: Mon, 15 Aug 2016 01:21:12 -0400
Subject: [PATCH] Validate that the cluster name is a valid DNS name

This should help users avoid the common mistake of just specifying the
name, not a fully-qualified domain name.

Fix #46
---
 upup/pkg/api/validation.go             | 14 ++++++++++++++
 upup/pkg/api/validation_test.go        | 15 +++++++++++++++
 upup/pkg/fi/cloudup/validation_test.go | 12 ++++++++++++
 3 files changed, 41 insertions(+)
 create mode 100644 upup/pkg/api/validation_test.go

diff --git a/upup/pkg/api/validation.go b/upup/pkg/api/validation.go
index 53886b653c714..7642abd7a0fb2 100644
--- a/upup/pkg/api/validation.go
+++ b/upup/pkg/api/validation.go
@@ -2,8 +2,10 @@ package api
 
 import (
 	"fmt"
+	"k8s.io/kubernetes/pkg/util/validation"
 	"net"
 	"net/url"
+	"strings"
 )
 
 func (c *Cluster) Validate(strict bool) error {
@@ -13,6 +15,18 @@ func (c *Cluster) Validate(strict bool) error {
 		return fmt.Errorf("Cluster Name is required (e.g. --name=mycluster.myzone.com)")
 	}
 
+	{
+		// Must be a dns name
+		errs := validation.IsDNS1123Subdomain(c.Name)
+		if len(errs) != 0 {
+			return fmt.Errorf("Cluster Name must be a valid DNS name (e.g. --name=mycluster.myzone.com) errors: %s", strings.Join(errs, ", "))
+		}
+
+		if !strings.Contains(c.Name, ".") {
+			return fmt.Errorf("Cluster Name must be a fully-qualified DNS name (e.g. --name=mycluster.myzone.com)")
+		}
+	}
+
 	if len(c.Spec.Zones) == 0 {
 		// TODO: Auto choose zones from region?
 		return fmt.Errorf("must configure at least one Zone (use --zones)")
diff --git a/upup/pkg/api/validation_test.go b/upup/pkg/api/validation_test.go
new file mode 100644
index 0000000000000..2f65226b55d05
--- /dev/null
+++ b/upup/pkg/api/validation_test.go
@@ -0,0 +1,15 @@
+package api
+
+import (
+	"testing"
+	"k8s.io/kubernetes/pkg/util/validation"
+)
+
+func Test_Validate_DNS(t *testing.T) {
+	for _, name := range []string{"test.-", "!", "-"} {
+		errs := validation.IsDNS1123Subdomain(name)
+		if len(errs) == 0 {
+			t.Fatalf("Expected errors validating name %q", name)
+		}
+	}
+}
diff --git a/upup/pkg/fi/cloudup/validation_test.go b/upup/pkg/fi/cloudup/validation_test.go
index a8bdc88c2227b..f71b4cf659af1 100644
--- a/upup/pkg/fi/cloudup/validation_test.go
+++ b/upup/pkg/fi/cloudup/validation_test.go
@@ -104,6 +104,18 @@ func TestValidateFull_Default_Validates(t *testing.T) {
 	}
 }
 
+func TestValidateFull_ClusterName_InvalidDNS_NoDot(t *testing.T) {
+	c := buildDefaultCluster(t)
+	c.Name = "test"
+	expectErrorFromValidate(t, c, "DNS name")
+}
+
+func TestValidateFull_ClusterName_InvalidDNS_Invalid(t *testing.T) {
+	c := buildDefaultCluster(t)
+	c.Name = "test.-"
+	expectErrorFromValidate(t, c, "DNS name")
+}
+
 func TestValidateFull_ClusterName_Required(t *testing.T) {
 	c := buildDefaultCluster(t)
 	c.Name = ""