Move oci and shim to execution package

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

execution/oci/oci.go

@@ -0,0 +1,142 @@
+package oci
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strconv"
+	"time"
+
+	"github.com/docker/containerd"
+)
+
+var ErrRootEmpty = errors.New("oci: runtime root cannot be an empty string")
+
+type Opts struct {
+	Name string
+	Root string
+	Args []string
+}
+
+func New(opts Opts) (*OCIRuntime, error) {
+	if opts.Root == "" {
+		return nil, ErrRootEmpty
+	}
+	if err := os.MkdirAll(opts.Root, 0711); err != nil {
+		return nil, err
+	}
+	return &OCIRuntime{
+		root: opts.Root,
+		name: opts.Name,
+		args: opts.Args,
+	}, nil
+}
+
+type OCIRuntime struct {
+	// root holds runtime state information for the containers
+	// launched by the runtime
+	root string
+	// name is the name of the runtime, i.e. runc
+	name string
+	// args specifies additional arguments to the OCI runtime
+	args []string
+}
+
+func (r *OCIRuntime) Name() string {
+	return r.name
+}
+
+func (r *OCIRuntime) Args() []string {
+	return r.args
+}
+
+func (r *OCIRuntime) Root() string {
+	return r.root
+}
+
+func (r *OCIRuntime) Create(c *containerd.Container) (containerd.ProcessDelegate, error) {
+	pidFile := fmt.Sprintf("%s/%s.pid", filepath.Join(r.root, c.ID()), "init")
+	cmd := r.Command("create", "--pid-file", pidFile, "--bundle", c.Path(), c.ID())
+	cmd.Stdin, cmd.Stdout, cmd.Stderr = c.Stdin, c.Stdout, c.Stderr
+	if err := cmd.Run(); err != nil {
+		return nil, err
+	}
+	data, err := ioutil.ReadFile(pidFile)
+	if err != nil {
+		return nil, err
+	}
+	i, err := strconv.Atoi(string(data))
+	if err != nil {
+		return nil, err
+	}
+	return newProcess(i)
+}
+
+func (r *OCIRuntime) Start(c *containerd.Container) error {
+	return r.Command("start", c.ID()).Run()
+}
+
+func (r *OCIRuntime) Delete(c *containerd.Container) error {
+	return r.Command("delete", c.ID()).Run()
+}
+
+func (r *OCIRuntime) Exec(c *containerd.Container, p *containerd.Process) (containerd.ProcessDelegate, error) {
+	f, err := ioutil.TempFile(filepath.Join(r.root, c.ID()), "process")
+	if err != nil {
+		return nil, err
+	}
+	path := f.Name()
+	pidFile := fmt.Sprintf("%s/%s.pid", filepath.Join(r.root, c.ID()), filepath.Base(path))
+	err = json.NewEncoder(f).Encode(p.Spec())
+	f.Close()
+	if err != nil {
+		return nil, err
+	}
+	cmd := r.Command("exec", "--detach", "--process", path, "--pid-file", pidFile, c.ID())
+	cmd.Stdin, cmd.Stdout, cmd.Stderr = p.Stdin, p.Stdout, p.Stderr
+	if err := cmd.Run(); err != nil {
+		return nil, err
+	}
+	data, err := ioutil.ReadFile(pidFile)
+	if err != nil {
+		return nil, err
+	}
+	i, err := strconv.Atoi(string(data))
+	if err != nil {
+		return nil, err
+	}
+	return newProcess(i)
+}
+
+type state struct {
+	ID          string            `json:"id"`
+	Pid         int               `json:"pid"`
+	Status      string            `json:"status"`
+	Bundle      string            `json:"bundle"`
+	Rootfs      string            `json:"rootfs"`
+	Created     time.Time         `json:"created"`
+	Annotations map[string]string `json:"annotations"`
+}
+
+func (r *OCIRuntime) Load(id string) (containerd.ProcessDelegate, error) {
+	data, err := r.Command("state", id).Output()
+	if err != nil {
+		return nil, err
+	}
+	var s state
+	if err := json.Unmarshal(data, &s); err != nil {
+		return nil, err
+	}
+	return newProcess(s.Pid)
+}
+
+func (r *OCIRuntime) Command(args ...string) *exec.Cmd {
+	baseArgs := append([]string{
+		"--root", r.root,
+	}, r.args...)
+	return exec.Command(r.name, append(baseArgs, args...)...)
+}