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)
+}

config.go

@@ -0,0 +1,18 @@
+package containerd
+
+type Process struct {
+	Args []string
+	Env  []string
+	Cwd  string
+	Uid  int
+	Gid  int
+	TTY  bool
+}
+
+type Config struct {
+	Process    Process
+	Hostname   string
+	Domain     string
+	Labels     map[string]string
+	StopSignal int
+}

specification/spec.go

@@ -0,0 +1,70 @@
+package specification
+
+import (
+	"runtime"
+
+	"github.com/docker/containerd"
+	"github.com/opencontainers/runtime-spec/specs-go"
+)
+
+var rwm = "rwm"
+
+func Default(config containerd.Config, mounts []containerd.Mount) *specs.Spec {
+	s := &specs.Spec{
+		Version: specs.Version,
+		Platform: specs.Platform{
+			OS:   runtime.GOOS,
+			Arch: runtime.GOARCH,
+		},
+		Root: specs.Root{
+			Path:     "rootfs",
+			Readonly: false,
+		},
+		Process: specs.Process{
+			Args:            config.Process.Args,
+			Env:             config.Process.Env,
+			Terminal:        config.Process.TTY,
+			Cwd:             config.Process.Cwd,
+			NoNewPrivileges: true,
+		},
+		Hostname: config.Hostname,
+		Linux: &specs.Linux{
+			Resources: &specs.LinuxResources{
+				Devices: []specs.LinuxDeviceCgroup{
+					{
+						Allow:  false,
+						Access: &rwm,
+					},
+				},
+			},
+			Namespaces: []specs.LinuxNamespace{
+				{
+					Type: "pid",
+				},
+				{
+					Type: "ipc",
+				},
+				{
+					Type: "uts",
+				},
+				{
+					Type: "mount",
+				},
+				{
+					Type: "network",
+				},
+			},
+		},
+		Annotations: config.Labels,
+	}
+	// apply snapshot mounts
+	for _, m := range mounts {
+		s.Mounts = append(s.Mounts, specs.Mount{
+			Source:      m.Source,
+			Destination: "/",
+			Type:        m.Type,
+			Options:     m.Options,
+		})
+	}
+	return s
+}