datasource: Move datasources into their own packages.

datasource/configdrive/configdrive.go

@@ -0,0 +1,69 @@
+package configdrive
+
+import (
+	"io/ioutil"
+	"os"
+	"path"
+)
+
+const (
+	ec2ApiVersion       = "2009-04-04"
+	openstackApiVersion = "latest"
+)
+
+type configDrive struct {
+	root     string
+	readFile func(filename string) ([]byte, error)
+}
+
+func NewDatasource(root string) *configDrive {
+	return &configDrive{path.Join(root, "openstack"), ioutil.ReadFile}
+}
+
+func (cd *configDrive) IsAvailable() bool {
+	_, err := os.Stat(cd.root)
+	return !os.IsNotExist(err)
+}
+
+func (cd *configDrive) AvailabilityChanges() bool {
+	return true
+}
+
+func (cd *configDrive) ConfigRoot() string {
+	return cd.openstackRoot()
+}
+
+// FetchMetadata attempts to retrieve metadata from ec2/2009-04-04/meta_data.json.
+func (cd *configDrive) FetchMetadata() ([]byte, error) {
+	return cd.tryReadFile(path.Join(cd.ec2Root(), "meta_data.json"))
+}
+
+// FetchUserdata attempts to retrieve the userdata from ec2/2009-04-04/user_data.
+// If no data is found, it will attempt to read from openstack/latest/user_data.
+func (cd *configDrive) FetchUserdata() ([]byte, error) {
+	bytes, err := cd.tryReadFile(path.Join(cd.ec2Root(), "user_data"))
+	if bytes == nil && err == nil {
+		bytes, err = cd.tryReadFile(path.Join(cd.openstackRoot(), "user_data"))
+	}
+	return bytes, err
+}
+
+func (cd *configDrive) Type() string {
+	return "cloud-drive"
+}
+
+func (cd *configDrive) ec2Root() string {
+	return path.Join(cd.root, "ec2", ec2ApiVersion)
+}
+
+func (cd *configDrive) openstackRoot() string {
+	return path.Join(cd.root, "openstack", openstackApiVersion)
+}
+
+func (cd *configDrive) tryReadFile(filename string) ([]byte, error) {
+	data, err := cd.readFile(filename)
+	if os.IsNotExist(err) {
+		err = nil
+	}
+	return data, err
+}

datasource/configdrive/configdrive_test.go

@@ -0,0 +1,114 @@
+package configdrive
+
+import (
+	"os"
+	"testing"
+)
+
+type mockFilesystem []string
+
+func (m mockFilesystem) readFile(filename string) ([]byte, error) {
+	for _, file := range m {
+		if file == filename {
+			return []byte(filename), nil
+		}
+	}
+	return nil, os.ErrNotExist
+}
+
+func TestCDFetchMetadata(t *testing.T) {
+	for _, tt := range []struct {
+		root     string
+		filename string
+		files    mockFilesystem
+	}{
+		{
+			"/",
+			"",
+			mockFilesystem{},
+		},
+		{
+			"/",
+			"/ec2/2009-04-04/meta_data.json",
+			mockFilesystem([]string{"/ec2/2009-04-04/meta_data.json"}),
+		},
+		{
+			"/media/configdrive",
+			"/media/configdrive/ec2/2009-04-04/meta_data.json",
+			mockFilesystem([]string{"/media/configdrive/ec2/2009-04-04/meta_data.json"}),
+		},
+	} {
+		cd := configDrive{tt.root, tt.files.readFile}
+		filename, err := cd.FetchMetadata()
+		if err != nil {
+			t.Fatalf("bad error for %q: want %q, got %q", tt, nil, err)
+		}
+		if string(filename) != tt.filename {
+			t.Fatalf("bad path for %q: want %q, got %q", tt, tt.filename, filename)
+		}
+	}
+}
+
+func TestCDFetchUserdata(t *testing.T) {
+	for _, tt := range []struct {
+		root     string
+		filename string
+		files    mockFilesystem
+	}{
+		{
+			"/",
+			"",
+			mockFilesystem{},
+		},
+		{
+			"/",
+			"/ec2/2009-04-04/user_data",
+			mockFilesystem([]string{"/ec2/2009-04-04/user_data"}),
+		},
+		{
+			"/",
+			"/openstack/latest/user_data",
+			mockFilesystem([]string{"/openstack/latest/user_data"}),
+		},
+		{
+			"/",
+			"/ec2/2009-04-04/user_data",
+			mockFilesystem([]string{"/openstack/latest/user_data", "/ec2/2009-04-04/user_data"}),
+		},
+		{
+			"/media/configdrive",
+			"/media/configdrive/ec2/2009-04-04/user_data",
+			mockFilesystem([]string{"/media/configdrive/ec2/2009-04-04/user_data"}),
+		},
+	} {
+		cd := configDrive{tt.root, tt.files.readFile}
+		filename, err := cd.FetchUserdata()
+		if err != nil {
+			t.Fatalf("bad error for %q: want %q, got %q", tt, nil, err)
+		}
+		if string(filename) != tt.filename {
+			t.Fatalf("bad path for %q: want %q, got %q", tt, tt.filename, filename)
+		}
+	}
+}
+
+func TestCDConfigRoot(t *testing.T) {
+	for _, tt := range []struct {
+		root       string
+		configRoot string
+	}{
+		{
+			"/",
+			"/openstack/latest",
+		},
+		{
+			"/media/configdrive",
+			"/media/configdrive/openstack/latest",
+		},
+	} {
+		cd := configDrive{tt.root, nil}
+		if configRoot := cd.ConfigRoot(); configRoot != tt.configRoot {
+			t.Fatalf("bad config root for %q: want %q, got %q", tt, tt.configRoot, configRoot)
+		}
+	}
+}