metadata: simplify merging of metadata

Add an internal field for CloudConfig to make it easier to distinguish.
Instead of creating two CloudConfigs and merging them, just merge the
metadata into the existing CloudConfig.

network/debian.go

@@ -19,9 +19,9 @@ import (
 	"strings"
 )
 
-func ProcessDebianNetconf(config string) ([]InterfaceGenerator, error) {
+func ProcessDebianNetconf(config []byte) ([]InterfaceGenerator, error) {
 	log.Println("Processing Debian network config")
-	lines := formatConfig(config)
+	lines := formatConfig(string(config))
 	stanzas, err := parseStanzas(lines)
 	if err != nil {
 		return nil, err

network/debian_test.go

@@ -44,7 +44,7 @@ func TestProcessDebianNetconf(t *testing.T) {
 		{"auto eth1\nauto eth2", false, 0},
 		{"iface eth1 inet manual", false, 1},
 	} {
-		interfaces, err := ProcessDebianNetconf(tt.in)
+		interfaces, err := ProcessDebianNetconf([]byte(tt.in))
 		failed := err != nil
 		if tt.fail != failed {
 			t.Fatalf("bad failure state for %q: got %t, want %t", tt.in, failed, tt.fail)

network/digitalocean.go

@@ -23,14 +23,14 @@ import (
 	"github.com/coreos/coreos-cloudinit/datasource/metadata/digitalocean"
 )
 
-func ProcessDigitalOceanNetconf(config string) ([]InterfaceGenerator, error) {
+func ProcessDigitalOceanNetconf(config []byte) ([]InterfaceGenerator, error) {
 	log.Println("Processing DigitalOcean network config")
-	if config == "" {
+	if len(config) == 0 {
 		return nil, nil
 	}
 
 	var cfg digitalocean.Metadata
-	if err := json.Unmarshal([]byte(config), &cfg); err != nil {
+	if err := json.Unmarshal(config, &cfg); err != nil {
 		return nil, err
 	}
 

network/digitalocean_test.go

@@ -378,7 +378,7 @@ func TestProcessDigitalOceanNetconf(t *testing.T) {
 			ifaces: []InterfaceGenerator{},
 		},
 	} {
-		ifaces, err := ProcessDigitalOceanNetconf(tt.cfg)
+		ifaces, err := ProcessDigitalOceanNetconf([]byte(tt.cfg))
 		if !errorsEqual(tt.err, err) {
 			t.Fatalf("bad error (%q): want %q, got %q", tt.cfg, tt.err, err)
 		}