Add runc support

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

runc/runc.go

@@ -0,0 +1,171 @@
+// +build runc
+
+package runc
+
+import (
+	"encoding/json"
+	"io/ioutil"
+	"os"
+	"os/exec"
+	"path/filepath"
+
+	"github.com/docker/containerd/runtime"
+	"github.com/opencontainers/specs"
+)
+
+func NewRuntime(stateDir string) (runtime.Runtime, error) {
+	return &runcRuntime{
+		stateDir: stateDir,
+	}, nil
+}
+
+type runcContainer struct {
+	id          string
+	path        string
+	stateDir    string
+	exitStatus  int
+	processes   map[int]*runcProcess
+	initProcess *runcProcess
+}
+
+func (c *runcContainer) ID() string {
+	return c.id
+}
+
+func (c *runcContainer) Start() error {
+	return c.initProcess.cmd.Start()
+}
+
+func (c *runcContainer) Path() string {
+	return c.path
+}
+
+func (c *runcContainer) Pid() (int, error) {
+	return c.initProcess.cmd.Process.Pid, nil
+}
+
+func (c *runcContainer) SetExited(status int) {
+	c.exitStatus = status
+}
+
+// noop for runc
+func (c *runcContainer) Delete() error {
+	return nil
+}
+
+func (c *runcContainer) Processes() ([]runtime.Process, error) {
+	procs := []runtime.Process{
+		c.initProcess,
+	}
+	for _, p := range c.processes {
+		procs = append(procs, p)
+	}
+	return procs, nil
+}
+
+func (c *runcContainer) RemoveProcess(pid int) error {
+	if _, ok := c.processes[pid]; !ok {
+		return runtime.ErrNotChildProcess
+	}
+	delete(c.processes, pid)
+	return nil
+}
+
+func (c *runcContainer) State() runtime.State {
+	// TODO: how to do this with runc
+	return runtime.State{
+		Status: runtime.Running,
+	}
+}
+
+func (c *runcContainer) Resume() error {
+	return c.newCommand("resume").Run()
+}
+
+func (c *runcContainer) Pause() error {
+	return c.newCommand("pause").Run()
+}
+
+func (c *runcContainer) newCommand(args ...string) *exec.Cmd {
+	cmd := exec.Command("runc", append([]string{"--root", c.stateDir, "--id", c.id}, args...)...)
+	cmd.Dir = c.path
+	return cmd
+}
+
+type runcProcess struct {
+	cmd  *exec.Cmd
+	spec specs.Process
+}
+
+// pid of the container, not of runc
+func (p *runcProcess) Pid() (int, error) {
+	return p.cmd.Process.Pid, nil
+}
+
+func (p *runcProcess) Spec() specs.Process {
+	return p.spec
+}
+
+func (p *runcProcess) Signal(s os.Signal) error {
+	return p.cmd.Process.Signal(s)
+}
+
+type runcRuntime struct {
+	stateDir string
+}
+
+func (r *runcRuntime) Create(id, bundlePath string, stdio *runtime.Stdio) (runtime.Container, error) {
+	cmd := exec.Command("runc", "--root", r.stateDir, "--id", id, "start")
+	cmd.Dir = bundlePath
+	//	cmd.Stderr = stdio.Stderr
+	//	cmd.Stdout = stdio.Stdout
+	var s specs.Spec
+	f, err := os.Open(filepath.Join(bundlePath, "config.json"))
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+	if err := json.NewDecoder(f).Decode(&s); err != nil {
+		return nil, err
+	}
+	return &runcContainer{
+		id:       id,
+		path:     bundlePath,
+		stateDir: r.stateDir,
+		initProcess: &runcProcess{
+			cmd:  cmd,
+			spec: s.Process,
+		},
+		processes: make(map[int]*runcProcess),
+	}, nil
+}
+
+func (r *runcRuntime) StartProcess(ci runtime.Container, p specs.Process, stdio *runtime.Stdio) (runtime.Process, error) {
+	c, ok := ci.(*runcContainer)
+	if !ok {
+		return nil, runtime.ErrInvalidContainerType
+	}
+	f, err := ioutil.TempFile("", "containerd")
+	if err != nil {
+		return nil, err
+	}
+	if err := json.NewEncoder(f).Encode(p); err != nil {
+		f.Close()
+		return nil, err
+	}
+	cmd := c.newCommand("exec", f.Name())
+	f.Close()
+	process := &runcProcess{
+		cmd:  cmd,
+		spec: p,
+	}
+	if err := cmd.Start(); err != nil {
+		return nil, err
+	}
+	pid, err := process.Pid()
+	if err != nil {
+		return nil, err
+	}
+	c.processes[pid] = process
+	return process, nil
+}

supervisor_unsupported.go

@@ -3,11 +3,10 @@
 package containerd
 
 import (
-	"errors"
-
+	"github.com/docker/containerd/runc"
 	"github.com/docker/containerd/runtime"
 )
 
 func newRuntime(stateDir string) (runtime.Runtime, error) {
-	return nil, errors.New("Unsupported runtime")
+	return runc.NewRuntime(stateDir)
 }