metadataService: Check both ec2 and openstack urls more explicitly

Remove the root url parameter for -from-metadata-service since this
is a guarenteed value. Additionally, check for both ec2 and openstack
urls for the metadata and userdata. Fix a bug with the -from-url
option and a panic on an empty response.

coreos-cloudinit.go

@@ -18,7 +18,7 @@ var (
 	sources       struct {
 		file            string
 		configDrive     string
-		metadataService string
+		metadataService bool
 		url             string
 		procCmdLine     bool
 	}
@@ -32,7 +32,7 @@ func init() {
 	flag.BoolVar(&ignoreFailure, "ignore-failure", false, "Exits with 0 status in the event of malformed input from user-data")
 	flag.StringVar(&sources.file, "from-file", "", "Read user-data from provided file")
 	flag.StringVar(&sources.configDrive, "from-configdrive", "", "Read data from provided cloud-drive directory")
-	flag.StringVar(&sources.metadataService, "from-metadata-service", "", "Download data from provided url")
+	flag.BoolVar(&sources.metadataService, "from-metadata-service", false, "Download data from metadata service")
 	flag.StringVar(&sources.url, "from-url", "", "Download user-data from provided url")
 	flag.BoolVar(&sources.procCmdLine, "from-proc-cmdline", false, fmt.Sprintf("Parse %s for '%s=<url>', using the cloud-config served by an HTTP GET to <url>", datasource.ProcCmdlineLocation, datasource.ProcCmdlineCloudConfigFlag))
 	flag.StringVar(&convertNetconf, "convert-netconf", "", "Read the network config provided in cloud-drive and translate it from the specified format into networkd unit files (requires the -from-configdrive flag)")
@@ -55,7 +55,7 @@ func main() {
 		os.Exit(0)
 	}
 
-	if convertNetconf != "" && sources.configDrive == "" && sources.metadataService == "" {
+	if convertNetconf != "" && sources.configDrive == "" && !sources.metadataService {
 		fmt.Println("-convert-netconf flag requires -from-configdrive or -from-metadata-service")
 		os.Exit(1)
 	}
@@ -127,15 +127,15 @@ func getDatasource() datasource.Datasource {
 		n++
 	}
 	if sources.url != "" {
-		ds = datasource.NewMetadataService(sources.url)
+		ds = datasource.NewRemoteFile(sources.url)
 		n++
 	}
 	if sources.configDrive != "" {
 		ds = datasource.NewConfigDrive(sources.configDrive)
 		n++
 	}
-	if sources.metadataService != "" {
-		ds = datasource.NewMetadataService(sources.metadataService)
+	if sources.metadataService {
+		ds = datasource.NewMetadataService()
 		n++
 	}
 	if sources.procCmdLine {

datasource/metadata_service.go

@@ -9,23 +9,34 @@ import (
 	"github.com/coreos/coreos-cloudinit/pkg"
 )
 
-// metadataService retrieves metadata from either an OpenStack[1] or EC2[2] compatible endpoint.
-// It will first attempt to directly retrieve a JSON blob from the OpenStack endpoint. If that
-// fails with a 404, it then attempts to retrieve metadata bit-by-bit from the EC2 endpoint,
-// and populates that into an equivalent JSON blob.
+// metadataService retrieves metadata from either an OpenStack[1] (2012-08-10)
+// or EC2[2] (2009-04-04) compatible endpoint. It will first attempt to
+// directly retrieve a JSON blob from the OpenStack endpoint. If that fails
+// with a 404, it then attempts to retrieve metadata bit-by-bit from the EC2
+// endpoint, and populates that into an equivalent JSON blob. metadataService
+// also checks for userdata from EC2 and, if that fails with a 404, OpenStack.
 //
 // [1] http://docs.openstack.org/grizzly/openstack-compute/admin/content/metadata-service.html
 // [2] http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/AESDG-chapter-instancedata.html#instancedata-data-categories
-type metadataService struct {
-	url string
-}
+
+const (
+	BaseUrl              = "http://169.254.169.254/"
+	Ec2ApiVersion        = "2009-04-04"
+	Ec2UserdataUrl       = BaseUrl + Ec2ApiVersion + "/user-data"
+	Ec2MetadataUrl       = BaseUrl + Ec2ApiVersion + "/meta-data/"
+	OpenstackApiVersion  = "openstack/2012-08-10"
+	OpenstackUserdataUrl = BaseUrl + OpenstackApiVersion + "/user_data"
+	OpenstackMetadataUrl = BaseUrl + OpenstackApiVersion + "/meta_data.json"
+)
+
+type metadataService struct{}
 
 type getter interface {
 	Get(string) ([]byte, error)
 }
 
-func NewMetadataService(url string) *metadataService {
-	return &metadataService{strings.TrimSuffix(url, "/")}
+func NewMetadataService() *metadataService {
+	return &metadataService{}
 }
 
 func (ms *metadataService) ConfigRoot() string {
@@ -33,27 +44,31 @@ func (ms *metadataService) ConfigRoot() string {
 }
 
 func (ms *metadataService) FetchMetadata() ([]byte, error) {
-	client := pkg.NewHttpClient()
-	return fetchMetadata(client, ms.url)
+	return fetchMetadata(pkg.NewHttpClient())
 }
 
 func (ms *metadataService) FetchUserdata() ([]byte, error) {
 	client := pkg.NewHttpClient()
-	return client.Get(ms.url + "/latest/user-data")
+	if data, err := client.Get(Ec2UserdataUrl); err == nil {
+		return data, err
+	} else if _, ok := err.(pkg.ErrTimeout); ok {
+		return data, err
+	}
+	return client.Get(OpenstackUserdataUrl)
 }
 
 func (ms *metadataService) Type() string {
 	return "metadata-service"
 }
 
-func fetchMetadata(client getter, url string) ([]byte, error) {
-	if metadata, err := client.Get(url + "/latest/meta-data.json"); err == nil {
+func fetchMetadata(client getter) ([]byte, error) {
+	if metadata, err := client.Get(OpenstackMetadataUrl); err == nil {
 		return metadata, nil
 	} else if _, ok := err.(pkg.ErrTimeout); ok {
 		return nil, err
 	}
 
-	attrs, err := fetchChildAttributes(client, url+"/latest/meta-data/")
+	attrs, err := fetchChildAttributes(client, Ec2MetadataUrl)
 	if err != nil {
 		return nil, err
 	}
@@ -74,7 +89,7 @@ func fetchAttributes(client getter, url string) ([]string, error) {
 }
 
 func fetchAttribute(client getter, url string) (interface{}, error) {
-	if attrs, err := fetchAttributes(client, url); err == nil {
+	if attrs, err := fetchAttributes(client, url); err == nil && len(attrs) > 0 {
 		return attrs[0], nil
 	} else {
 		return "", err

datasource/metadata_service_test.go

@@ -137,19 +137,19 @@ func TestFetchMetadata(t *testing.T) {
 	}{
 		{
 			metadata: map[string]string{
-				"/latest/meta-data/":      "a\nb\nc/",
-				"/latest/meta-data/c/":    "d\ne/",
-				"/latest/meta-data/c/e/":  "f",
-				"/latest/meta-data/a":     "1",
-				"/latest/meta-data/b":     "2",
-				"/latest/meta-data/c/d":   "3",
-				"/latest/meta-data/c/e/f": "4",
+				"http://169.254.169.254/2009-04-04/meta-data/":      "a\nb\nc/",
+				"http://169.254.169.254/2009-04-04/meta-data/c/":    "d\ne/",
+				"http://169.254.169.254/2009-04-04/meta-data/c/e/":  "f",
+				"http://169.254.169.254/2009-04-04/meta-data/a":     "1",
+				"http://169.254.169.254/2009-04-04/meta-data/b":     "2",
+				"http://169.254.169.254/2009-04-04/meta-data/c/d":   "3",
+				"http://169.254.169.254/2009-04-04/meta-data/c/e/f": "4",
 			},
 			expect: []byte(`{"a":"1","b":"2","c":{"d":"3","e":{"f":"4"}}}`),
 		},
 		{
 			metadata: map[string]string{
-				"/latest/meta-data.json": "test",
+				"http://169.254.169.254/openstack/2012-08-10/meta_data.json": "test",
 			},
 			expect: []byte("test"),
 		},
@@ -157,7 +157,7 @@ func TestFetchMetadata(t *testing.T) {
 		{err: pkg.ErrNotFound{fmt.Errorf("test error")}},
 	} {
 		client := &TestHttpClient{tt.metadata, tt.err}
-		metadata, err := fetchMetadata(client, "")
+		metadata, err := fetchMetadata(client)
 		if err != tt.err {
 			t.Fatalf("bad error (%q): want %q, got %q", tt.metadata, tt.err, err)
 		}