Add basic bundle, spec, and config types

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

bundle/bundle.go

@@ -0,0 +1,62 @@
+package bundle
+
+import (
+	"encoding/json"
+	"os"
+	"path/filepath"
+
+	"github.com/opencontainers/runtime-spec/specs-go"
+)
+
+const configName = "config.json"
+
+func New(path string, s *specs.Spec) (*Bundle, error) {
+	if err := os.Mkdir(path, 0700); err != nil {
+		return nil, err
+	}
+	b := &Bundle{
+		Path: path,
+	}
+	if err := os.Mkdir(filepath.Join(path, "rootfs"), 0700); err != nil {
+		b.Delete()
+		return nil, err
+	}
+	f, err := os.Create(filepath.Join(path, configName))
+	if err != nil {
+		b.Delete()
+		return nil, err
+	}
+	err = json.NewEncoder(f).Encode(s)
+	f.Close()
+	if err != nil {
+		b.Delete()
+		return nil, err
+	}
+	return b, nil
+}
+
+func Load(path string) (*Bundle, error) {
+	// TODO: do validation
+	return &Bundle{
+		Path: path,
+	}, nil
+}
+
+type Bundle struct {
+	Path string
+}
+
+func (b *Bundle) Config() (*specs.Spec, error) {
+	var s specs.Spec
+	f, err := os.Open(filepath.Join(b.Path, configName))
+	if err != nil {
+		return nil, err
+	}
+	err = json.NewDecoder(f).Decode(&s)
+	f.Close()
+	return &s, err
+}
+
+func (b *Bundle) Delete() error {
+	return os.RemoveAll(b.Path)
+}