datasource: replace metadata map with struct

The loosely-typed metadata map is a load of crap. Make it a struct and
let the compiler help us out.

datasource/metadata/digitalocean/metadata.go

@@ -16,8 +16,10 @@ package digitalocean
 
 import (
 	"encoding/json"
+	"net"
 	"strconv"
 
+	"github.com/coreos/coreos-cloudinit/datasource"
 	"github.com/coreos/coreos-cloudinit/datasource/metadata"
 )
 
@@ -68,45 +70,43 @@ func NewDatasource(root string) *metadataService {
 	return &metadataService{MetadataService: metadata.NewDatasource(root, apiVersion, userdataUrl, metadataPath)}
 }
 
-func (ms *metadataService) FetchMetadata() ([]byte, error) {
-	data, err := ms.FetchData(ms.MetadataUrl())
-	if err != nil || len(data) == 0 {
-		return []byte{}, err
+func (ms *metadataService) FetchMetadata() (metadata datasource.Metadata, err error) {
+	var data []byte
+	var m Metadata
+
+	if data, err = ms.FetchData(ms.MetadataUrl()); err != nil || len(data) == 0 {
+		return
+	}
+	if err = json.Unmarshal(data, &m); err != nil {
+		return
 	}
 
-	var metadata Metadata
-	if err := json.Unmarshal(data, &metadata); err != nil {
-		return []byte{}, err
+	ms.interfaces = m.Interfaces
+	ms.dns = m.DNS
+
+	if len(m.Interfaces.Public) > 0 {
+		if m.Interfaces.Public[0].IPv4 != nil {
+			metadata.PublicIPv4 = net.ParseIP(m.Interfaces.Public[0].IPv4.IPAddress)
+		}
+		if m.Interfaces.Public[0].IPv6 != nil {
+			metadata.PublicIPv6 = net.ParseIP(m.Interfaces.Public[0].IPv6.IPAddress)
+		}
+	}
+	if len(m.Interfaces.Private) > 0 {
+		if m.Interfaces.Private[0].IPv4 != nil {
+			metadata.PrivateIPv4 = net.ParseIP(m.Interfaces.Private[0].IPv4.IPAddress)
+		}
+		if m.Interfaces.Private[0].IPv6 != nil {
+			metadata.PrivateIPv6 = net.ParseIP(m.Interfaces.Private[0].IPv6.IPAddress)
+		}
+	}
+	metadata.Hostname = m.Hostname
+	metadata.SSHPublicKeys = map[string]string{}
+	for i, key := range m.PublicKeys {
+		metadata.SSHPublicKeys[strconv.Itoa(i)] = key
 	}
 
-	ms.interfaces = metadata.Interfaces
-	ms.dns = metadata.DNS
-
-	attrs := make(map[string]interface{})
-	if len(metadata.Interfaces.Public) > 0 {
-		if metadata.Interfaces.Public[0].IPv4 != nil {
-			attrs["public-ipv4"] = metadata.Interfaces.Public[0].IPv4.IPAddress
-		}
-		if metadata.Interfaces.Public[0].IPv6 != nil {
-			attrs["public-ipv6"] = metadata.Interfaces.Public[0].IPv6.IPAddress
-		}
-	}
-	if len(metadata.Interfaces.Private) > 0 {
-		if metadata.Interfaces.Private[0].IPv4 != nil {
-			attrs["local-ipv4"] = metadata.Interfaces.Private[0].IPv4.IPAddress
-		}
-		if metadata.Interfaces.Private[0].IPv6 != nil {
-			attrs["local-ipv6"] = metadata.Interfaces.Private[0].IPv6.IPAddress
-		}
-	}
-	attrs["hostname"] = metadata.Hostname
-	keys := make(map[string]string)
-	for i, key := range metadata.PublicKeys {
-		keys[strconv.Itoa(i)] = key
-	}
-	attrs["public_keys"] = keys
-
-	return json.Marshal(attrs)
+	return
 }
 
 func (ms metadataService) FetchNetworkConfig(filename string) ([]byte, error) {

datasource/metadata/digitalocean/metadata_test.go

@@ -15,10 +15,12 @@
 package digitalocean
 
 import (
-	"bytes"
 	"fmt"
+	"net"
+	"reflect"
 	"testing"
 
+	"github.com/coreos/coreos-cloudinit/datasource"
 	"github.com/coreos/coreos-cloudinit/datasource/metadata"
 	"github.com/coreos/coreos-cloudinit/datasource/metadata/test"
 	"github.com/coreos/coreos-cloudinit/pkg"
@@ -36,7 +38,7 @@ func TestFetchMetadata(t *testing.T) {
 		root         string
 		metadataPath string
 		resources    map[string]string
-		expect       []byte
+		expect       datasource.Metadata
 		clientErr    error
 		expectErr    error
 	}{
@@ -81,7 +83,14 @@ func TestFetchMetadata(t *testing.T) {
   }
 }`,
 			},
-			expect: []byte(`{"hostname":"","public-ipv4":"192.168.1.2","public-ipv6":"fe00::","public_keys":{"0":"publickey1","1":"publickey2"}}`),
+			expect: datasource.Metadata{
+				PublicIPv4: net.ParseIP("192.168.1.2"),
+				PublicIPv6: net.ParseIP("fe00::"),
+				SSHPublicKeys: map[string]string{
+					"0": "publickey1",
+					"1": "publickey2",
+				},
+			},
 		},
 		{
 			clientErr: pkg.ErrTimeout{Err: fmt.Errorf("test error")},
@@ -99,8 +108,8 @@ func TestFetchMetadata(t *testing.T) {
 		if Error(err) != Error(tt.expectErr) {
 			t.Fatalf("bad error (%q): want %q, got %q", tt.resources, tt.expectErr, err)
 		}
-		if !bytes.Equal(metadata, tt.expect) {
-			t.Fatalf("bad fetch (%q): want %q, got %q", tt.resources, tt.expect, metadata)
+		if !reflect.DeepEqual(tt.expect, metadata) {
+			t.Fatalf("bad fetch (%q): want %#q, got %#q", tt.resources, tt.expect, metadata)
 		}
 	}
 }