cloudinit: retrieve IPv4 addresses from metadata

This uses the new MetadataService implementation to retrieve values for
$private_ipv4 and $public_ipv4 substitutions, instead of using
environment variables.

coreos-cloudinit.go

@@ -86,7 +86,16 @@ func main() {
 		die()
 	}
 
-	env := initialize.NewEnvironment("/", ds.ConfigRoot(), workspace, convertNetconf, sshKeyName)
+	var subs map[string]string
+	if len(metadataBytes) > 0 {
+		subs, err = initialize.ExtractIPsFromMetadata(metadataBytes)
+		if err != nil {
+			fmt.Printf("Failed extracting IPs from meta-data: %v\n", err)
+			die()
+		}
+	}
+	env := initialize.NewEnvironment("/", ds.ConfigRoot(), workspace, convertNetconf, sshKeyName, subs)
+
 	if len(userdataBytes) > 0 {
 		if err := processUserdata(string(userdataBytes), env); err != nil {
 			fmt.Printf("Failed to process user-data: %v\n", err)

initialize/env.go

@@ -1,7 +1,6 @@
 package initialize
 
 import (
-	"os"
 	"path"
 	"strings"
 )
@@ -17,11 +16,8 @@ type Environment struct {
 	substitutions map[string]string
 }
 
-func NewEnvironment(root, configRoot, workspace, netconfType, sshKeyName string) *Environment {
-	substitutions := map[string]string{
-		"$public_ipv4":  os.Getenv("COREOS_PUBLIC_IPV4"),
-		"$private_ipv4": os.Getenv("COREOS_PRIVATE_IPV4"),
-	}
+// TODO(jonboulle): this is getting unwieldy, should be able to simplify the interface somehow
+func NewEnvironment(root, configRoot, workspace, netconfType, sshKeyName string, substitutions map[string]string) *Environment {
 	return &Environment{root, configRoot, workspace, netconfType, sshKeyName, substitutions}
 }
 

initialize/env_test.go

@@ -1,14 +1,13 @@
 package initialize
 
-import (
-	"os"
-	"testing"
-)
+import "testing"
 
 func TestEnvironmentApply(t *testing.T) {
-	os.Setenv("COREOS_PUBLIC_IPV4", "192.0.2.3")
-	os.Setenv("COREOS_PRIVATE_IPV4", "192.0.2.203")
-	env := NewEnvironment("./", "./", "./", "", "")
+	subs := map[string]string{
+		"$public_ipv4":  "192.0.2.3",
+		"$private_ipv4": "192.0.2.203",
+	}
+	env := NewEnvironment("./", "./", "./", "", "", subs)
 	input := `[Service]
 ExecStart=/usr/bin/echo "$public_ipv4"
 ExecStop=/usr/bin/echo $private_ipv4

initialize/meta_data.go

@@ -1,9 +1,9 @@
 package initialize
 
-import (
-	"encoding/json"
-)
+import "encoding/json"
 
+// ParseMetaData parses a JSON blob in the OpenStack metadata service format, and
+// converts it to a CloudConfig
 func ParseMetaData(contents string) (cfg CloudConfig, err error) {
 	var metadata struct {
 		SSHAuthorizedKeyMap map[string]string `json:"public_keys"`
@@ -24,3 +24,23 @@ func ParseMetaData(contents string) (cfg CloudConfig, err error) {
 	cfg.NetworkConfigPath = metadata.NetworkConfig.ContentPath
 	return
 }
+
+// ExtractIPsFromMetaData parses a JSON blob in the OpenStack metadata service format,
+// and returns a substitution map possibly containing private_ipv4 and public_ipv4 addresses
+func ExtractIPsFromMetadata(contents []byte) (map[string]string, error) {
+	var ips struct {
+		Public  string `json:"public-ipv4"`
+		Private string `json:"local-ipv4"`
+	}
+	if err := json.Unmarshal(contents, &ips); err != nil {
+		return nil, err
+	}
+	m := make(map[string]string)
+	if ips.Private != "" {
+		m["$private_ipv4"] = ips.Private
+	}
+	if ips.Public != "" {
+		m["$public_ipv4"] = ips.Public
+	}
+	return m, nil
+}

initialize/meta_data_test.go

@@ -0,0 +1,36 @@
+package initialize
+
+import "reflect"
+import "testing"
+
+func TestExtractIPsFromMetadata(t *testing.T) {
+	for i, tt := range []struct {
+		in  []byte
+		err bool
+		out map[string]string
+	}{
+		{
+			[]byte(`{"public-ipv4": "12.34.56.78", "local-ipv4": "1.2.3.4"}`),
+			false,
+			map[string]string{"$public_ipv4": "12.34.56.78", "$private_ipv4": "1.2.3.4"},
+		},
+		{
+			[]byte(`{"local-ipv4": "127.0.0.1", "something_else": "don't care"}`),
+			false,
+			map[string]string{"$private_ipv4": "127.0.0.1"},
+		},
+		{
+			[]byte(`garbage`),
+			true,
+			nil,
+		},
+	} {
+		got, err := ExtractIPsFromMetadata(tt.in)
+		if (err != nil) != tt.err {
+			t.Errorf("bad error state (got %t, want %t)", err != nil, tt.err)
+		}
+		if !reflect.DeepEqual(got, tt.out) {
+			t.Errorf("case %d: got %s, want %s", i, got, tt.out)
+		}
+	}
+}