containerd/oci/oci.go
Michael Crosby 3551d4c0b9 Implement live restore with shim
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
2016-10-06 15:18:26 -07:00

142 lines
3.3 KiB
Go

package oci
import (
"encoding/json"
"errors"
"fmt"
"io/ioutil"
"os"
"os/exec"
"path/filepath"
"strconv"
"time"
"github.com/docker/containerkit"
)
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 *containerkit.Container) (containerkit.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 *containerkit.Container) error {
return r.Command("start", c.ID()).Run()
}
func (r *OCIRuntime) Delete(c *containerkit.Container) error {
return r.Command("delete", c.ID()).Run()
}
func (r *OCIRuntime) Exec(c *containerkit.Container, p *containerkit.Process) (containerkit.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) (containerkit.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...)...)
}