package docker
import (
"container/list"
"fmt"
"github.com/dotcloud/docker/auth"
"io"
"io/ioutil"
"log"
"os"
"os/exec"
"path"
"sort"
"strings"
"time"
)
type Capabilities struct {
MemoryLimit bool
SwapLimit bool
}
type Runtime struct {
root string
repository string
containers *list.List
networkManager *NetworkManager
graph *Graph
repositories *TagStore
authConfig *auth.AuthConfig
idIndex *TruncIndex
capabilities *Capabilities
kernelVersion *KernelVersionInfo
}
var sysInitPath string
func init() {
sysInitPath = SelfPath()
}
func (runtime *Runtime) List() []*Container {
containers := new(History)
for e := runtime.containers.Front(); e != nil; e = e.Next() {
containers.Add(e.Value.(*Container))
}
return *containers
}
func (runtime *Runtime) getContainerElement(id string) *list.Element {
for e := runtime.containers.Front(); e != nil; e = e.Next() {
container := e.Value.(*Container)
if container.Id == id {
return e
}
}
return nil
}
func (runtime *Runtime) Get(name string) *Container {
id, err := runtime.idIndex.Get(name)
if err != nil {
return nil
}
e := runtime.getContainerElement(id)
if e == nil {
return nil
}
return e.Value.(*Container)
}
func (runtime *Runtime) Exists(id string) bool {
return runtime.Get(id) != nil
}
func (runtime *Runtime) containerRoot(id string) string {
return path.Join(runtime.repository, id)
}
func (runtime *Runtime) Create(config *Config) (*Container, error) {
// Lookup image
img, err := runtime.repositories.LookupImage(config.Image)
if err != nil {
return nil, err
}
// Generate id
id := GenerateId()
// Generate default hostname
// FIXME: the lxc template no longer needs to set a default hostname
if config.Hostname == "" {
config.Hostname = id[:12]
}
container := &Container{
// FIXME: we should generate the ID here instead of receiving it as an argument
Id: id,
Created: time.Now(),
Path: config.Cmd[0],
Args: config.Cmd[1:], //FIXME: de-duplicate from config
Config: config,
Image: img.Id, // Always use the resolved image id
NetworkSettings: &NetworkSettings{},
// FIXME: do we need to store this in the container?
SysInitPath: sysInitPath,
}
container.root = runtime.containerRoot(container.Id)
// Step 1: create the container directory.
// This doubles as a barrier to avoid race conditions.
if err := os.Mkdir(container.root, 0700); err != nil {
return nil, err
}
// If custom dns exists, then create a resolv.conf for the container
if len(config.Dns) > 0 {
container.ResolvConfPath = path.Join(container.root, "resolv.conf")
f, err := os.Create(container.ResolvConfPath)
if err != nil {
return nil, err
}
defer f.Close()
for _, dns := range config.Dns {
if _, err := f.Write([]byte("nameserver " + dns + "\n")); err != nil {
return nil, err
}
}
} else {
container.ResolvConfPath = "/etc/resolv.conf"
}
// Step 2: save the container json
if err := container.ToDisk(); err != nil {
return nil, err
}
// Step 3: register the container
if err := runtime.Register(container); err != nil {
return nil, err
}
return container, nil
}
func (runtime *Runtime) Load(id string) (*Container, error) {
container := &Container{root: runtime.containerRoot(id)}
if err := container.FromDisk(); err != nil {
return nil, err
}
if container.Id != id {
return container, fmt.Errorf("Container %s is stored at %s", container.Id, id)
}
if container.State.Running {
container.State.Ghost = true
}
if err := runtime.Register(container); err != nil {
return nil, err
}
return container, nil
}
// Register makes a container object usable by the runtime as <container.Id>
func (runtime *Runtime) Register(container *Container) error {
if container.runtime != nil || runtime.Exists(container.Id) {
return fmt.Errorf("Container is already loaded")
}
if err := validateId(container.Id); err != nil {
return err
}
// init the wait lock
container.waitLock = make(chan struct{})
// FIXME: if the container is supposed to be running but is not, auto restart it?
// if so, then we need to restart monitor and init a new lock
// If the container is supposed to be running, make sure of it
if container.State.Running {
if output, err := exec.Command("lxc-info", "-n", container.Id).CombinedOutput(); err != nil {
return err
} else {
if !strings.Contains(string(output), "RUNNING") {
Debugf("Container %s was supposed to be running be is not.", container.Id)
container.State.setStopped(-127)
if err := container.ToDisk(); err != nil {
return err
}
}
}
}
// If the container is not running or just has been flagged not running
// then close the wait lock chan (will be reset upon start)
if !container.State.Running {
close(container.waitLock)
}
// Even if not running, we init the lock (prevents races in start/stop/kill)
container.State.initLock()
container.runtime = runtime
// Attach to stdout and stderr
container.stderr = newWriteBroadcaster()
container.stdout = newWriteBroadcaster()
// Attach to stdin
if container.Config.OpenStdin {
container.stdin, container.stdinPipe = io.Pipe()
} else {
container.stdinPipe = NopWriteCloser(ioutil.Discard) // Silently drop stdin
}
// done
runtime.containers.PushBack(container)
runtime.idIndex.Add(container.Id)
return nil
}
func (runtime *Runtime) LogToDisk(src *writeBroadcaster, dst string) error {
log, err := os.OpenFile(dst, os.O_RDWR|os.O_APPEND|os.O_CREATE, 0600)
if err != nil {
return err
}
src.AddWriter(log)
return nil
}
func (runtime *Runtime) Destroy(container *Container) error {
element := runtime.getContainerElement(container.Id)
if element == nil {
return fmt.Errorf("Container %v not found - maybe it was already destroyed?", container.Id)
}
if err := container.Stop(10); err != nil {
return err
}
if mounted, err := container.Mounted(); err != nil {
return err
} else if mounted {
if err := container.Unmount(); err != nil {
return fmt.Errorf("Unable to unmount container %v: %v", container.Id, err)
}
}
// Deregister the container before removing its directory, to avoid race conditions
runtime.idIndex.Delete(container.Id)
runtime.containers.Remove(element)
if err := os.RemoveAll(container.root); err != nil {
return fmt.Errorf("Unable to remove filesystem for %v: %v", container.Id, err)
}
return nil
}
// Commit creates a new filesystem image from the current state of a container.
// The image can optionally be tagged into a repository
func (runtime *Runtime) Commit(id, repository, tag, comment, author string) (*Image, error) {
container := runtime.Get(id)
if container == nil {
return nil, fmt.Errorf("No such container: %s", id)
}
// FIXME: freeze the container before copying it to avoid data corruption?
// FIXME: this shouldn't be in commands.
rwTar, err := container.ExportRw()
if err != nil {
return nil, err
}
// Create a new image from the container's base layers + a new layer from container changes
img, err := runtime.graph.Create(rwTar, container, comment, author)
if err != nil {
return nil, err
}
// Register the image if needed
if repository != "" {
if err := runtime.repositories.Set(repository, tag, img.Id, true); err != nil {
return img, err
}
}
return img, nil
}
func (runtime *Runtime) restore() error {
dir, err := ioutil.ReadDir(runtime.repository)
if err != nil {
return err
}
for _, v := range dir {
id := v.Name()
container, err := runtime.Load(id)
if err != nil {
Debugf("Failed to load container %v: %v", id, err)
continue
}
Debugf("Loaded container %v", container.Id)
}
return nil
}
// FIXME: harmonize with NewGraph()
func NewRuntime() (*Runtime, error) {
runtime, err := NewRuntimeFromDirectory("/var/lib/docker")
if err != nil {
return nil, err
}
if k, err := GetKernelVersion(); err != nil {
log.Printf("WARNING: %s\n", err)
} else {
runtime.kernelVersion = k
if CompareKernelVersion(k, &KernelVersionInfo{Kernel: 3, Major: 8, Minor: 0}) < 0 {
log.Printf("WARNING: You are running linux kernel version %s, which might be unstable running docker. Please upgrade your kernel to 3.8.0.", k.String())
}
}
if cgroupMemoryMountpoint, err := FindCgroupMountpoint("memory"); err != nil {
log.Printf("WARNING: %s\n", err)
} else {
_, err1 := ioutil.ReadFile(path.Join(cgroupMemoryMountpoint, "memory.limit_in_bytes"))
_, err2 := ioutil.ReadFile(path.Join(cgroupMemoryMountpoint, "memory.soft_limit_in_bytes"))
runtime.capabilities.MemoryLimit = err1 == nil && err2 == nil
if !runtime.capabilities.MemoryLimit {
log.Printf("WARNING: Your kernel does not support cgroup memory limit.")
}
_, err = ioutil.ReadFile(path.Join(cgroupMemoryMountpoint, "memory.memsw.limit_in_bytes"))
runtime.capabilities.SwapLimit = err == nil
if !runtime.capabilities.SwapLimit {
log.Printf("WARNING: Your kernel does not support cgroup swap limit.")
}
}
return runtime, nil
}
func NewRuntimeFromDirectory(root string) (*Runtime, error) {
runtimeRepo := path.Join(root, "containers")
if err := os.MkdirAll(runtimeRepo, 0700); err != nil && !os.IsExist(err) {
return nil, err
}
g, err := NewGraph(path.Join(root, "graph"))
if err != nil {
return nil, err
}
repositories, err := NewTagStore(path.Join(root, "repositories"), g)
if err != nil {
return nil, fmt.Errorf("Couldn't create Tag store: %s", err)
}
if NetworkBridgeIface == "" {
NetworkBridgeIface = DefaultNetworkBridge
}
netManager, err := newNetworkManager(NetworkBridgeIface)
if err != nil {
return nil, err
}
authConfig, err := auth.LoadConfig(root)
if err != nil && authConfig == nil {
// If the auth file does not exist, keep going
return nil, err
}
runtime := &Runtime{
root: root,
repository: runtimeRepo,
containers: list.New(),
networkManager: netManager,
graph: g,
repositories: repositories,
authConfig: authConfig,
idIndex: NewTruncIndex(),
capabilities: &Capabilities{},
}
if err := runtime.restore(); err != nil {
return nil, err
}
return runtime, nil
}
type History []*Container
func (history *History) Len() int {
return len(*history)
}
func (history *History) Less(i, j int) bool {
containers := *history
return containers[j].When().Before(containers[i].When())
}
func (history *History) Swap(i, j int) {
containers := *history
tmp := containers[i]
containers[i] = containers[j]
containers[j] = tmp
}
func (history *History) Add(container *Container) {
*history = append(*history, container)
sort.Sort(history)
}