fix(etcd): Transform DISCOVERY_URL to DISCOVERY

Documentation/cloud-config.md

@@ -87,7 +87,7 @@ For example, the following cloud-config document...
 coreos:
     etcd:
         name: node001
-        discovery-url: https://discovery.etcd.io/3445fa65423d8b04df07f59fb40218f8
+        discovery: https://discovery.etcd.io/3445fa65423d8b04df07f59fb40218f8
         bind-addr: $public_ipv4:4001
         peer-bind-addr: $private_ipv4:7001
 ```
@@ -97,7 +97,7 @@ coreos:
 ```
 [Service]
 Environment="ETCD_NAME=node001""
-Environment="ETCD_DISCOVERY_URL=https://discovery.etcd.io/3445fa65423d8b04df07f59fb40218f8"
+Environment="ETCD_DISCOVERY=https://discovery.etcd.io/3445fa65423d8b04df07f59fb40218f8"
 Environment="ETCD_BIND_ADDR=203.0.113.29:4001"
 Environment="ETCD_PEER_BIND_ADDR=192.0.2.13:7001"
 ```
@@ -136,7 +136,7 @@ echo 'Hello, world!'
 
 coreos:
 	etcd:
-		discovery_url: https://discovery.etcd.io/827c73219eeb2fa5530027c37bf18877
+		discovery: https://discovery.etcd.io/827c73219eeb2fa5530027c37bf18877
     fleet:
         autostart: yes
 ssh_authorized_keys:

initialize/config_test.go

@@ -35,7 +35,7 @@ func TestCloudConfig(t *testing.T) {
 	contents := []byte(`
 coreos: 
   etcd:
-    discovery_url: "https://discovery.etcd.io/827c73219eeb2fa5530027c37bf18877"
+    discovery: "https://discovery.etcd.io/827c73219eeb2fa5530027c37bf18877"
   fleet:
     autostart: Yes
   units:

initialize/etcd.go

@@ -12,16 +12,32 @@ import (
 
 type EtcdEnvironment map[string]string
 
+func (ec EtcdEnvironment) normalized() map[string]string {
+	out := make(map[string]string, len(ec))
+	for key, val := range ec {
+		key = strings.ToUpper(key)
+		key = strings.Replace(key, "-", "_", -1)
+		out[key] = val
+	}
+	return out
+}
+
 func (ec EtcdEnvironment) String() (out string) {
+	norm := ec.normalized()
+
+	if val, ok := norm["DISCOVERY_URL"]; ok {
+		delete(norm, "DISCOVERY_URL")
+		if _, ok := norm["DISCOVERY"]; !ok {
+			norm["DISCOVERY"] = val
+		}
+	}
+
 	public := os.Getenv("COREOS_PUBLIC_IPV4")
 	private := os.Getenv("COREOS_PRIVATE_IPV4")
 
 	out += "[Service]\n"
 
-	for key, val := range ec {
+	for key, val := range norm {
-		key = strings.ToUpper(key)
-		key = strings.Replace(key, "-", "_", -1)
-
 		if public != "" {
 			val = strings.Replace(val, "$public_ipv4", public, -1)
 		}

initialize/etcd_test.go

@@ -10,13 +10,46 @@ import (
 )
 
 func TestEtcdEnvironment(t *testing.T) {
+	cfg := make(EtcdEnvironment, 0)
+	cfg["discovery"] = "http://disco.example.com/foobar"
+	cfg["peer-bind-addr"] = "127.0.0.1:7002"
+
+	env := cfg.String()
+	expect := `[Service]
+Environment="ETCD_DISCOVERY=http://disco.example.com/foobar"
+Environment="ETCD_PEER_BIND_ADDR=127.0.0.1:7002"
+`
+
+	if env != expect {
+		t.Errorf("Generated environment:\n%s\nExpected environment:\n%s", env, expect)
+	}
+}
+
+func TestEtcdEnvironmentDiscoveryURLTranslated(t *testing.T) {
 	cfg := make(EtcdEnvironment, 0)
 	cfg["discovery_url"] = "http://disco.example.com/foobar"
 	cfg["peer-bind-addr"] = "127.0.0.1:7002"
 
 	env := cfg.String()
 	expect := `[Service]
-Environment="ETCD_DISCOVERY_URL=http://disco.example.com/foobar"
+Environment="ETCD_DISCOVERY=http://disco.example.com/foobar"
+Environment="ETCD_PEER_BIND_ADDR=127.0.0.1:7002"
+`
+
+	if env != expect {
+		t.Errorf("Generated environment:\n%s\nExpected environment:\n%s", env, expect)
+	}
+}
+
+func TestEtcdEnvironmentDiscoveryOverridesDiscoveryURL(t *testing.T) {
+	cfg := make(EtcdEnvironment, 0)
+	cfg["discovery_url"] = "ping"
+	cfg["discovery"] = "pong"
+	cfg["peer-bind-addr"] = "127.0.0.1:7002"
+
+	env := cfg.String()
+	expect := `[Service]
+Environment="ETCD_DISCOVERY=pong"
 Environment="ETCD_PEER_BIND_ADDR=127.0.0.1:7002"
 `
 
@@ -47,7 +80,7 @@ Environment="ETCD_PEER_BIND_ADDR=192.0.2.13:7001"
 func TestEtcdEnvironmentWrittenToDisk(t *testing.T) {
 	ec := EtcdEnvironment{
 		"name": "node001",
-		"discovery_url": "http://disco.example.com/foobar",
+		"discovery": "http://disco.example.com/foobar",
 		"peer-bind-addr": "127.0.0.1:7002",
 	}
 	dir, err := ioutil.TempDir(os.TempDir(), "coreos-cloudinit-")
@@ -78,7 +111,7 @@ func TestEtcdEnvironmentWrittenToDisk(t *testing.T) {
 
 	expect := `[Service]
 Environment="ETCD_NAME=node001"
-Environment="ETCD_DISCOVERY_URL=http://disco.example.com/foobar"
+Environment="ETCD_DISCOVERY=http://disco.example.com/foobar"
 Environment="ETCD_PEER_BIND_ADDR=127.0.0.1:7002"
 `
 	if string(contents) != expect {