package docker
import (
"./fs"
"encoding/json"
"errors"
"github.com/kr/pty"
"io"
"io/ioutil"
"log"
"os"
"os/exec"
"path"
"strconv"
"syscall"
"time"
)
var sysInitPath string
func init() {
sysInitPath = SelfPath()
}
type Container struct {
Id string
Root string
Created time.Time
Path string
Args []string
Config *Config
Mountpoint *fs.Mountpoint
State *State
Image string
network *NetworkInterface
networkManager *NetworkManager
NetworkSettings *NetworkSettings
SysInitPath string
lxcConfigPath string
cmd *exec.Cmd
stdout *writeBroadcaster
stderr *writeBroadcaster
stdin io.ReadCloser
stdinPipe io.WriteCloser
stdoutLog *os.File
stderrLog *os.File
}
type Config struct {
Hostname string
User string
Memory int64 // Memory limit (in bytes)
MemorySwap int64 // Total memory usage (memory + swap); set `-1' to disable swap
Ports []int
Tty bool // Attach standard streams to a tty, including stdin if it is not closed.
OpenStdin bool // Open stdin
}
type NetworkSettings struct {
IpAddress string
IpPrefixLen int
Gateway string
PortMapping map[string]string
}
func createContainer(id string, root string, command string, args []string, image *fs.Image, config *Config, netManager *NetworkManager) (*Container, error) {
mountpoint, err := image.Mountpoint(path.Join(root, "rootfs"), path.Join(root, "rw"))
if err != nil {
return nil, err
}
container := &Container{
Id: id,
Root: root,
Created: time.Now(),
Path: command,
Args: args,
Config: config,
Image: image.Id,
Mountpoint: mountpoint,
State: newState(),
networkManager: netManager,
NetworkSettings: &NetworkSettings{},
SysInitPath: sysInitPath,
lxcConfigPath: path.Join(root, "config.lxc"),
stdout: newWriteBroadcaster(),
stderr: newWriteBroadcaster(),
}
if err := os.Mkdir(root, 0700); err != nil {
return nil, err
}
// Setup logging of stdout and stderr to disk
if stdoutLog, err := os.OpenFile(path.Join(container.Root, id+"-stdout.log"), os.O_RDWR|os.O_APPEND|os.O_CREATE, 0600); err != nil {
return nil, err
} else {
container.stdoutLog = stdoutLog
}
if stderrLog, err := os.OpenFile(path.Join(container.Root, id+"-stderr.log"), os.O_RDWR|os.O_APPEND|os.O_CREATE, 0600); err != nil {
return nil, err
} else {
container.stderrLog = stderrLog
}
if container.Config.OpenStdin {
container.stdin, container.stdinPipe = io.Pipe()
} else {
container.stdinPipe = NopWriteCloser(ioutil.Discard) // Silently drop stdin
}
container.stdout.AddWriter(NopWriteCloser(container.stdoutLog))
container.stderr.AddWriter(NopWriteCloser(container.stderrLog))
if err := container.save(); err != nil {
return nil, err
}
return container, nil
}
func loadContainer(store *fs.Store, containerPath string, netManager *NetworkManager) (*Container, error) {
data, err := ioutil.ReadFile(path.Join(containerPath, "config.json"))
if err != nil {
return nil, err
}
mountpoint, err := store.FetchMountpoint(
path.Join(containerPath, "rootfs"),
path.Join(containerPath, "rw"),
)
if err != nil {
return nil, err
} else if mountpoint == nil {
return nil, errors.New("Couldn't load container: unregistered mountpoint.")
}
container := &Container{
stdout: newWriteBroadcaster(),
stderr: newWriteBroadcaster(),
lxcConfigPath: path.Join(containerPath, "config.lxc"),
networkManager: netManager,
NetworkSettings: &NetworkSettings{},
Mountpoint: mountpoint,
}
// Load container settings
if err := json.Unmarshal(data, container); err != nil {
return nil, err
}
// Setup logging of stdout and stderr to disk
if stdoutLog, err := os.OpenFile(path.Join(container.Root, container.Id+"-stdout.log"), os.O_RDWR|os.O_APPEND|os.O_CREATE, 0600); err != nil {
return nil, err
} else {
container.stdoutLog = stdoutLog
}
if stderrLog, err := os.OpenFile(path.Join(container.Root, container.Id+"-stderr.log"), os.O_RDWR|os.O_APPEND|os.O_CREATE, 0600); err != nil {
return nil, err
} else {
container.stderrLog = stderrLog
}
container.stdout.AddWriter(NopWriteCloser(container.stdoutLog))
container.stderr.AddWriter(NopWriteCloser(container.stderrLog))
if container.Config.OpenStdin {
container.stdin, container.stdinPipe = io.Pipe()
} else {
container.stdinPipe = NopWriteCloser(ioutil.Discard) // Silently drop stdin
}
container.State = newState()
return container, nil
}
func (container *Container) Cmd() *exec.Cmd {
return container.cmd
}
func (container *Container) When() time.Time {
return container.Created
}
func (container *Container) loadUserData() (map[string]string, error) {
jsonData, err := ioutil.ReadFile(path.Join(container.Root, "userdata.json"))
if err != nil {
if os.IsNotExist(err) {
return make(map[string]string), nil
}
return nil, err
}
data := make(map[string]string)
if err := json.Unmarshal(jsonData, &data); err != nil {
return nil, err
}
return data, nil
}
func (container *Container) saveUserData(data map[string]string) error {
jsonData, err := json.Marshal(data)
if err != nil {
return err
}
return ioutil.WriteFile(path.Join(container.Root, "userdata.json"), jsonData, 0700)
}
func (container *Container) SetUserData(key, value string) error {
data, err := container.loadUserData()
if err != nil {
return err
}
data[key] = value
return container.saveUserData(data)
}
func (container *Container) GetUserData(key string) string {
data, err := container.loadUserData()
if err != nil {
return ""
}
if value, exists := data[key]; exists {
return value
}
return ""
}
func (container *Container) save() (err error) {
data, err := json.Marshal(container)
if err != nil {
return
}
return ioutil.WriteFile(path.Join(container.Root, "config.json"), data, 0666)
}
func (container *Container) generateLXCConfig() error {
fo, err := os.Create(container.lxcConfigPath)
if err != nil {
return err
}
defer fo.Close()
if err := LxcTemplateCompiled.Execute(fo, container); err != nil {
return err
}
return nil
}
func (container *Container) startPty() error {
stdout_master, stdout_slave, err := pty.Open()
if err != nil {
return err
}
container.cmd.Stdout = stdout_slave
stderr_master, stderr_slave, err := pty.Open()
if err != nil {
return err
}
container.cmd.Stderr = stderr_slave
// Copy the PTYs to our broadcasters
go func() {
defer container.stdout.Close()
io.Copy(container.stdout, stdout_master)
}()
go func() {
defer container.stderr.Close()
io.Copy(container.stderr, stderr_master)
}()
// stdin
var stdin_slave io.ReadCloser
if container.Config.OpenStdin {
stdin_master, stdin_slave, err := pty.Open()
if err != nil {
return err
}
container.cmd.Stdin = stdin_slave
// FIXME: The following appears to be broken.
// "cannot set terminal process group (-1): Inappropriate ioctl for device"
// container.cmd.SysProcAttr = &syscall.SysProcAttr{Setctty: true, Setsid: true}
go func() {
defer container.stdin.Close()
io.Copy(stdin_master, container.stdin)
}()
}
if err := container.cmd.Start(); err != nil {
return err
}
stdout_slave.Close()
stderr_slave.Close()
if stdin_slave != nil {
stdin_slave.Close()
}
return nil
}
func (container *Container) start() error {
container.cmd.Stdout = container.stdout
container.cmd.Stderr = container.stderr
if container.Config.OpenStdin {
stdin, err := container.cmd.StdinPipe()
if err != nil {
return err
}
go func() {
defer stdin.Close()
io.Copy(stdin, container.stdin)
}()
}
return container.cmd.Start()
}
func (container *Container) Start() error {
if err := container.Mountpoint.EnsureMounted(); err != nil {
return err
}
if err := container.allocateNetwork(); err != nil {
return err
}
if err := container.generateLXCConfig(); err != nil {
return err
}
params := []string{
"-n", container.Id,
"-f", container.lxcConfigPath,
"--",
"/sbin/init",
}
// Networking
params = append(params, "-g", container.network.Gateway.String())
// User
if container.Config.User != "" {
params = append(params, "-u", container.Config.User)
}
// Program
params = append(params, "--", container.Path)
params = append(params, container.Args...)
container.cmd = exec.Command("/usr/bin/lxc-start", params...)
var err error
if container.Config.Tty {
err = container.startPty()
} else {
err = container.start()
}
if err != nil {
return err
}
container.State.setRunning(container.cmd.Process.Pid)
container.save()
go container.monitor()
return nil
}
func (container *Container) Run() error {
if err := container.Start(); err != nil {
return err
}
container.Wait()
return nil
}
func (container *Container) Output() (output []byte, err error) {
pipe, err := container.StdoutPipe()
if err != nil {
return nil, err
}
defer pipe.Close()
if err := container.Start(); err != nil {
return nil, err
}
output, err = ioutil.ReadAll(pipe)
container.Wait()
return output, err
}
// StdinPipe() returns a pipe connected to the standard input of the container's
// active process.
//
func (container *Container) StdinPipe() (io.WriteCloser, error) {
return container.stdinPipe, nil
}
func (container *Container) StdoutPipe() (io.ReadCloser, error) {
reader, writer := io.Pipe()
container.stdout.AddWriter(writer)
return newBufReader(reader), nil
}
func (container *Container) StdoutLog() io.Reader {
r, err := os.Open(container.stdoutLog.Name())
if err != nil {
return nil
}
return r
}
func (container *Container) StderrPipe() (io.ReadCloser, error) {
reader, writer := io.Pipe()
container.stderr.AddWriter(writer)
return newBufReader(reader), nil
}
func (container *Container) StderrLog() io.Reader {
r, err := os.Open(container.stderrLog.Name())
if err != nil {
return nil
}
return r
}
func (container *Container) allocateNetwork() error {
iface, err := container.networkManager.Allocate()
if err != nil {
return err
}
container.NetworkSettings.PortMapping = make(map[string]string)
for _, port := range container.Config.Ports {
if extPort, err := iface.AllocatePort(port); err != nil {
iface.Release()
return err
} else {
container.NetworkSettings.PortMapping[strconv.Itoa(port)] = strconv.Itoa(extPort)
}
}
container.network = iface
container.NetworkSettings.IpAddress = iface.IPNet.IP.String()
container.NetworkSettings.IpPrefixLen, _ = iface.IPNet.Mask.Size()
container.NetworkSettings.Gateway = iface.Gateway.String()
return nil
}
func (container *Container) releaseNetwork() error {
err := container.network.Release()
container.network = nil
container.NetworkSettings = &NetworkSettings{}
return err
}
func (container *Container) monitor() {
// Wait for the program to exit
container.cmd.Wait()
exitCode := container.cmd.ProcessState.Sys().(syscall.WaitStatus).ExitStatus()
// Cleanup
if err := container.releaseNetwork(); err != nil {
log.Printf("%v: Failed to release network: %v", container.Id, err)
}
container.stdout.Close()
container.stderr.Close()
if err := container.Mountpoint.Umount(); err != nil {
log.Printf("%v: Failed to umount filesystem: %v", container.Id, err)
}
// Re-create a brand new stdin pipe once the container exited
if container.Config.OpenStdin {
container.stdin, container.stdinPipe = io.Pipe()
}
// Report status back
container.State.setStopped(exitCode)
container.save()
}
func (container *Container) kill() error {
if err := container.cmd.Process.Kill(); err != nil {
return err
}
// Wait for the container to be actually stopped
container.Wait()
return nil
}
func (container *Container) Kill() error {
if !container.State.Running {
return nil
}
return container.kill()
}
func (container *Container) Stop() error {
if !container.State.Running {
return nil
}
// 1. Send a SIGTERM
if output, err := exec.Command("/usr/bin/lxc-kill", "-n", container.Id, "15").CombinedOutput(); err != nil {
log.Printf(string(output))
log.Printf("Failed to send SIGTERM to the process, force killing")
if err := container.Kill(); err != nil {
return err
}
}
// 2. Wait for the process to exit on its own
if err := container.WaitTimeout(10 * time.Second); err != nil {
log.Printf("Container %v failed to exit within 10 seconds of SIGTERM - using the force", container.Id)
if err := container.Kill(); err != nil {
return err
}
}
return nil
}
func (container *Container) Restart() error {
if err := container.Stop(); err != nil {
return err
}
if err := container.Start(); err != nil {
return err
}
return nil
}
// Wait blocks until the container stops running, then returns its exit code.
func (container *Container) Wait() int {
for container.State.Running {
container.State.wait()
}
return container.State.ExitCode
}
func (container *Container) WaitTimeout(timeout time.Duration) error {
done := make(chan bool)
go func() {
container.Wait()
done <- true
}()
select {
case <-time.After(timeout):
return errors.New("Timed Out")
case <-done:
return nil
}
return nil
}